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COPGD988V
Datasheet (NSC)
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Datasheet COPGD988V, COPGD888V Datasheet (NSC)

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Page 1
COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D
General Description
The COP888GD ROM based microcontrollers are highly in­tegrated COP8
™
Feature core devices with 16k memory and advanced features including an A/D Converter. These multi-chip CMOS devices are suited for applications requir­ing a full featured controller with an 8-bitA/D converter, and as pre-production devices for a masked ROM design. Pin and software compatible 16k or 32k OTP EPROM versions are available (COP87L88GD/RD Family) for pre-production, and for use with a range of COP8 software and hardware de­velopment tools.
Family features include an 8-bit memory mapped architec­ture, 10 MHz CKI with 1µs instruction cycle, three multi­function 16-bit timer/counters, MICROWIRE/PLUS
™
serial I/O, one 8-bit/8-channel A/D converter with prescaler and both differential and single ended modes, two power saving HALT/IDLE modes, MIWU, idle timer, high current outputs, software selectable I/O options, WATCHDOG
™
timer and Clock Monitor, 2.5V to 5.5V operation, program code secu­rity, and 44 pin package.
Devices included in this datasheet are:
Device Memory (bytes) RAM (bytes) I/O Pins Packages Temperature Comments
COP688GD 16k ROM 256 40 44 PLCC -55 to +125˚C 4.5V to 5.5V COP888GD 16k ROM 256 40 44 PLCC -40 to +85˚C 2.5V to 5.5V COP988GD 16k ROM 256 40 44 PLCC 0 to +70˚C 2.5V to 4.0V, GDH = 4.0V to
6.0V
Key Features
n 8-channel A/D converter with prescaler and both
differential and single ended modes
n Three 16-bit timers, each with two 16-bit registers
supporting: — Processor Independent PWM mode — External Event counter mode — Input Capture mode
n Quiet design (low radiated emissions) n 16 kbytes on-board ROM n 256 bytes on-board RAM
Additional Peripheral Features
n Idle Timer n Multi-Input Wakeup (MIWU) with optional interrupts (8) n WATCHDOG and clock monitor logic n MICROWIRE/PLUS serial I/O
I/O Features
n Memory mapped I/O n Software selectable I/O options (TRI-STATE
®
Output, Push-Pull Output, Weak Pull Up Input, High Impedance Input)
n Schmitt trigger inputs on ports G and L n Package:
— 44 PLCC with 40 I/O pins
CPU/Instruction Set Features
n 1 µs instruction cycle time n Twelve multi-source vectored interrupts servicing
— External Interrupt — Idle Timer T0 — Three Timers (each with 2 Interrupts) — MICROWIRE/PLUS — Multi-Input Wake Up — Software Trap — Default VIS (default interrupt)
n Versatile and easy to use instruction set n 8-bit Stack Pointer (SP) – stack in RAM n Two 8-bit Register Indirect Data Memory Pointers (B
and X)
Fully Static CMOS
n Two power saving modes: HALT and IDLE n Single supply operation: 2.5V to 5.5V n Temperature range: −0˚C to +70˚C and −40˚C to +85˚C
Development Support
n Emulation and OTP devices n Real time emulation and full program debug offered by
MetaLink Development System
TRI-STATE®is a registered trademark of National Semiconductor Corporation. MICROWIRE/PLUS
™
, COP8™, MICROWIRE™and WATCHDOG™are trademarks of National Semiconductor Corporation.
iceMASTER
®
is a registered trademark of MetaLink Corporation.
July 1999
COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D
© 1999 National Semiconductor Corporation DS100076 www.national.com
Page 2
Block Diagram
Connection Diagrams
DS100076-1
FIGURE 1. Block Diagram
Plastic Chip Carrier
DS100076-2
Top View
Order Number COP888GD-XXXV, COP988GD-XXX/V
See NS Plastic Chip Package Number V44A
FIGURE 2. Connection Diagrams
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Page 3
Connection Diagrams (Continued)
Pinouts for 44-Pin Package
Port Type Alt. Fun Alt. Fun
44-Pin
Pack.
L0 I/O MIWU 17 L1 I/O MIWU 18 L2 I/O MIWU 19 L3 I/O MIWU 20 L4 I/O MIWU T2A 25 L5 I/O MIWU T2B 26 L6 I/O MIWU T3A 27 L7 I/O MIWU T3B 28 G0 I/O INT 39 G1 WDOUT 40 G2 I/O T1B 41 G3 I/O T1A 42 G4 I/O SO 3 G5 I/O SK 4 G6 I SI 5 G7 I/CKO HALT Restart 6 D0 O 29 D1 O 30 D2 O 31 D3 O 32 D4 O 33 D5 O 34 D6 O 35 D7 O 36 I0 I ACH0 9 I1 I ACH1 10 I2 I ACH2 11 I3 I ACH3 12 I4 I ACH4 13 I5 I ACH5 14 I6 I ACH6 15 I7 I ACH7 16 C0 I/O 43 C1 I/O 44 C2 I/O 1 C3 I/O 2 C4 I/O 21 C5 I/O 22 C6 I/O 23 C7 I/O 24 V
CC
8 GND 37 CKI 7 RESET
38
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Page 4
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
Supply Voltage (V
CC
)7V
Voltage at Any Pin −0.3V to V
CC
+ 0.3V
Total Current into V
CC
Pin
(Source) 100 mA
Total Current out of GND Pin
(Sink) 110 mA
Storage Temperature Range −65˚C to +140˚C
Note 1:
Absolute maximum ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications are not ensured when operating the device at absolute maximum ratings.
DC Electrical Characteristics
−0˚C ≤ TA≤ +70˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
Operating Voltage 2.5 5.5 V Power Supply Ripple (Note 3) Peak-to-Peak 0.1 V
CC
V
Supply Current (Note 4)
CKI = 10 MHz V
CC
= 5.5V, tc=1µs 20 mA
CKI = 4 MHz V
CC
= 4.0V, tc= 2.5
µs
10 mA
HALT Current (Note 5) V
CC
= 5.5V, CKI = 0
MHz
12 µA
V
CC
= 4.0V, CKI = 0
MHz
10 µA
IDLE Current (Note 4)
CKI = 10 MHz V
CC
= 5.5V, tc= 1 µs 1.2 mA
CKI = 4 MHz V
CC
= 4.0V, tc= 2.5
µs
1mA
Input Levels RESET , CKI
Logic High 0.8
V
CC
V
Logic Low 0.2 V
CC
V
All Other Inputs (L0-L7, G0-G6, C0-C7, I0-I7)
Logic High 0.7
V
CC
V
Logic Low 0.2 V
CC
V
Hi-Z Input Leakage V
CC
= 5.5V −2 +2 µA
Input Pullup Current V
CC
= 5.5V, VIN= 0V −40 −250 µA
G and L Port Input Hysteresis (Note 9) 0.35
V
CC
V
Output Current Levels D Outputs
Source V
CC
= 4.5V, VOH=
3.3V
−0.4 mA
Sink (Note 6) V
CC
= 4.5V, VOL=1V 10 mA
All Others
Source (Weak Pull-Up Mode) V
CC
= 4.5V, VOH=
2.7V
−10 −100 µA
Source (Push-Pull Mode) V
CC
= 4.5V, VOH=
3.3V
−0.4 mA
Sink (Push-Pull Mode) V
CC
= 4.5V, VOL=
0.4V
1.6 mA
TRI-STATE Leakage V
CC
= 5.5V −2 +2 µA
Allowable Sink/Source Current per Pin
D Outputs (Sink) 15 mA
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Page 5
DC Electrical Characteristics (Continued)
−0˚C ≤ TA≤ +70˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
All others 3mA
Maximum Input Current Room Temp
±
100 mA without Latchup (Note 7) (Note 9) RAM Retention Voltage, V
r
500 ns Rise 2 V
and Fall Time (min) Input Capacitance 7pF Load Capacitance on D2 1000 pF
Note 2: tc= Instruction Cycle Time Note 3: Maximum rate of voltage change must be
<
0.5 V/ms.
Note 4: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to V
CC
and outputs driven low but not connected to a load. Note 5: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of I
DD
HALTis done with device neither sourcing nor sinking current; with L,C,G0,andG2–G5 programmed as low outputs and not drivingaload;alloutputsprogrammedlowandnotdrivingaload; all inputs tied to V
CC
; clock monitor and comparator disabled. Parameter refers to HALTmode entered via setting bit 7 of the G Port data register. Part will pull up
CKI during HALT in crystal clock mode. Note 6: The user must guarantee that D2 pin does not source more than 10 mA during RESET.If D2 sources more than 10 mA during reset, the device will go into
programming mode. Note 7: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages V
CC
and the pins will have sink current to VCCwhen biased at voltages VCC(the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCCis 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to
<
14V.WARNING:Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD
transients.
Note 8: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 9: Parameter characterized but not tested.
AC Electrical Characteristics
−40˚C ≤ TA≤ +85˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
Instruction Cycle Time (t
c
)
Crystal, Resonator, 4.5V ≤ V
CC
≤ 5.5V 1.0 DC µs
R/C Oscillator 4.5V ≤ V
CC
≤ 5.5V 3.0 DC µs
CKI Clock Duty Cycle (Note 9) f
r
= Max 40 60
Rise Time (Note 9) f
r
= 10 MHz Ext Clock 5 ns
Fall Time (Note 9) f
r
= 10 MHz Ext Clock 5 ns
Inputs
t
SETUP
4.5V ≤ VCC≤ 5.5V 200 ns
t
HOLD
4.5V ≤ VCC≤ 5.5V 60 ns
Output Propagation Delay (Note 8) R
L
= 2.2k, CL= 100 pF
t
PD1,tPD0
SO, SK 4.5V ≤ VCC≤ 5.5V 0.7 µs All Others 4.5V ≤ V
CC
≤ 5.5V 1.0 µs
MICROWIRE
™
Setup Time (t
UWS
) (Note
9)
20 ns
MICROWIRE Hold Time (t
UWH
) (Note 9) 56 ns
MICROWIRE Output Propagation Delay (t
UPD
)
220 ns
Input Pulse Width (Note 9)
Interrupt Input High Time 1.0 t
c
Interrupt Input Low Time 1.0 t
c
Timer 1, 2, 3 Input High Time 1.0 t
c
Timer 1, 2, 3 Input Low Time 1.0 t
c
Reset Pulse Width 1.0 µs
Note 10: tc= Instruction Cycle Time Note 11: Maximum rate of voltage change must be
<
0.5 V/ms.
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Page 6
AC Electrical Characteristics (Continued)
Note 12: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to V
CC
and outputs driven low but not connected to a load. Note 13: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of I
DD
HALTisdonewithdevice neither sourcing nor sinking current; with L,C,G0,andG2–G5 programmed as low outputs and not drivingaload;alloutputsprogrammedlowandnotdrivingaload; all inputs tied to V
CC
; clock monitor and comparator disabled. Parameter refers to HALTmode entered via setting bit 7 of the G Port data register. Part will pull up
CKI during HALT in crystal clock mode. Note 14: The user must guarantee that D2 pin does not source more than 10 mA during RESET.If D2 sources more than 10 mA during reset, the device will go into
programming mode. Note 15: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages V
CC
and the pins will have sink current to VCCwhen biased at voltages VCC(the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCCis 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to
<
14V.WARNING:Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD
transients.
Note 16: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 17: Parameter characterized but not tested.
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Page 7
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
Supply Voltage (V
CC
)7V
Voltage at Any Pin −0.3V to V
CC
+ 0.3V
Total Current into V
CC
Pin
(Source) 100 mA
Total Current out of GND Pin
(Sink) 110 mA
Storage Temperature Range −65˚C to +140˚C
Note 18:
Absolute maximum ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications are not ensured when operating the device at absolute maximum ratings.
DC Electrical Characteristics
−40˚C ≤ TA≤ +85˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
Operating Voltage 2.7 5.5 V Power Supply Ripple (Note 3) Peak-to-Peak 0.1 V
CC
V
Supply Current (Note 4)
CKI = 10 MHz V
CC
= 5.5V, tc=1µs 20 mA
CKI = 4 MHz V
CC
= 4.0V, tc= 2.5
µs
10 mA
HALT Current (Note 5) V
CC
= 5.5V, CKI = 0
MHz
12 µA
V
CC
= 4.0V, CKI = 0
MHz
10 µA
IDLE Current (Note 4)
CKI = 10 MHz V
CC
= 5.5V, tc= 1 µs 1.2 mA
CKI = 4 MHz V
CC
= 4.0V, tc= 2.5
µs
1mA
Input Levels RESET , CKI
Logic High 0.8
V
CC
V
Logic Low 0.2 V
CC
V
All Other Inputs (L0-L7, G0-G6, C0-C7, I0-I7)
Logic High 0.7
V
CC
V
Logic Low 0.2 V
CC
V
Hi-Z Input Leakage V
CC
= 5.5V −2 +2 µA
Input Pullup Current V
CC
= 5.5V, VIN= 0V −40 −250 µA
G and L Port Input Hysteresis (Note 9) 0.35
V
CC
V
Output Current Levels D Outputs
Source V
CC
= 4.5V, VOH=
3.3V
−0.4 mA
Sink (Note 6) V
CC
= 4.5V, VOL=1V 10 mA
All Others
Source (Weak Pull-Up Mode) V
CC
= 4.5V, VOH=
2.7V
−10 −100 µA
Source (Push-Pull Mode) V
CC
= 4.5V, VOH=
3.3V
−0.4 mA
Sink (Push-Pull Mode) V
CC
= 4.5V, VOL=
0.4V
1.6 mA
TRI-STATE Leakage V
CC
= 5.5V −2 +2 µA
Allowable Sink/Source Current per Pin
D Outputs (Sink) 15 mA
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Page 8
DC Electrical Characteristics (Continued)
−40˚C ≤ TA≤ +85˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
All others 3mA
Maximum Input Current Room Temp
±
100 mA without Latchup (Note 7) (Note 9) RAM Retention Voltage, V
r
500 ns Rise 2 V
and Fall Time (min) Input Capacitance 7pF Load Capacitance on D2 1000 pF
AC Electrical Characteristics
−40˚C ≤ TA≤ +85˚C unless otherwise specified
Parameter Conditions Min Typ Max Units
Instruction Cycle Time (t
c
)
Crystal, Resonator, 4.5V ≤ V
CC
≤ 5.5V 1.0 DC µs
R/C Oscillator 4.5V ≤ V
CC
≤ 5.5V 3.0 DC µs
CKI Clock Duty Cycle (Note 9) f
r
= Max 40 60
Rise Time (Note 9) f
r
= 10 MHz Ext Clock 5 ns
Fall Time (Note 9) f
r
= 10 MHz Ext Clock 5 ns
Inputs
t
SETUP
4.5V ≤ VCC≤ 5.5V 200 ns
t
HOLD
4.5V ≤ VCC≤ 5.5V 60 ns
Output Propagation Delay (Note 8) R
L
= 2.2k, CL= 100 pF
t
PD1,tPD0
SO, SK 4.5V ≤ VCC≤ 5.5V 0.7 µs All Others 4.5V ≤ V
CC
≤ 5.5V 1.0 µs
MICROWIRE Setup Time (t
UWS
) (Note 9) 20 ns
MICROWIRE Hold Time (t
UWH
) (Note 9) 56 ns
MICROWIRE Output Propagation Delay (t
UPD
)
220 ns
Input Pulse Width (Note 9)
Interrupt Input High Time 1.0 t
c
Interrupt Input Low Time 1.0 t
c
Timer 1, 2, 3 Input High Time 1.0 t
c
Timer 1, 2, 3 Input Low Time 1.0 t
c
Reset Pulse Width 1.0 µs
Note 19: tc= Instruction Cycle Time Note 20: Maximum rate of voltage change must be
<
0.5 V/ms.
Note 21: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to V
CC
and outputs driven low but not connected to a load. Note 22: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of I
DD
HALTisdonewithdevice neither sourcing nor sinking current; with L,C,G0,andG2–G5 programmed as low outputs and not drivingaload;alloutputsprogrammedlowandnotdrivingaload; all inputs tied to V
CC
; clock monitor and comparator disabled. Parameter refers to HALTmode entered via setting bit 7 of the G Port data register. Part will pull up
CKI during HALT in crystal clock mode. Note 23: The user must guarantee that D2 pin does not source more than 10 mA during RESET.If D2 sources more than 10 mA during reset, the device will go into
programming mode. Note 24: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages V
CC
and the pins will have sink current to VCCwhen biased at voltages VCC(the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCCis 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to
<
14V.WARNING:Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD
transients.
Note 25: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 26: Parameter characterized but not tested.
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Page 9
A/D Converter Specifications
VCC=5V±10%,(VSS–0.050V) ≤ Any Input ≤ (VCC+ 0.050V)
Parameter Conditions Min Typ Max Units
Resolution 8 Bits Absolute Accuracy
±
2 LSB
Non-Linearity Deviation from the Best Straight
Line
±
1 LSB
Differential Non-Linearity
±
1 LSB
Common Mode Input Range GND V
CC
V
DC Common Mode Error
±
1/2 LSB Off Channel Leakage Current 1 2 µA On Channel Leakage Current 1 2 µA A/D Clock Frequency 0.1 1.67 MHz Converison Time 17 A/D Clock Cycles Internal Reference Resistance 1µs Tum-on Time
Note 27: Conversion Time includes 7 A/D clock cycles sample and hold time. Note 28: See Prescaler description. Note 29: For V
IN
(−)=VIN(+) the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input. The diodes will forward conduct for analog
input voltages below ground or above the V
CC
supply.Be careful, during testing at low VCClevels (4.5V), as high level analog inputs (5V) can cause this input diode to conduct—especiallyatelevatedtemperatures,andcauseerrorsforanaloginputsnearfull-scale.Thespecallows50mVforward bias of either diode. This means that as long as the analog V
IN
does not exceed the supply voltage by more than 50 mV, the output code will be correct. Toachieve an absolute 0 VDCto5VDCinput
voltage range will therefore require a minimum supply voltage of 4.950 V
DC
over temperature variations, initial tolerance and loading.
Note 30: Time or internal reference reistance to turn on and settle after coming out of HALT or IDLE mode.
DS100076-4
FIGURE 3. MICROWIRE/PLUS Timing
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Page 10
Typical Performance Characteristics (−55˚C ≤ T
A
=
+125˚C)
DS100076-19 DS100076-20
DS100076-21 DS100076-22
DS100076-23
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Page 11
Pin Descriptions
VCCand GND are the power supply pins. All VCCand GND pins must be connected.
CKI is the clock input. This can come from an R/C generated oscillator, or a crystal oscillator (in conjunction with CKO). See Oscillator Description section.
RESET is the master reset input. See Reset Description sec­tion.
The device contains three bidirectional 8-bit I/O ports (C, G and L), where each individual bit may be independently con­figured as an input (Schmitt Trigger inputs on ports L and G), output or TRI-STATE under program control. Three data memory address locations are allocated for each of these I/O ports. Each I/O port has two associated 8-bit memory mapped registers, the CONFIGURATION register and the output DATAregister. A memory mapped address is also re­served for the input pins of each I/O port. (See the memory map for the various addresses associated with the I/O ports.)
Figure 4
shows the I/O port configurations. The DATA and CONFIGURATION registers allow for each port bit to be in­dividually configured under software control as shown below:
CONFIGURATION DATA Port Set-Up
Register Register
0 0 Hi-Z Input
(TRI-STATE Output) 0 1 Input with Weak Pull-Up 1 0 Push-Pull Zero Output 1 1 Push-Pull One Output
PORT L is an 8-bit I/O port. All L-pins have Schmitt triggers on the inputs.
Port L supports Multi-Input Wake Up on all eight pins. L4 and L5 are used for the timer input functions T2A and T2B. L6 and L7 are used for the timer input functions T3A and T3B.
Port L has the following alternate features:
L7 MIWU or T3B L6 MIWU or T3A L5 MIWU or T2B L4 MIWU or T2A L3 MIWU L2 MIWU L1 MIWU L0 MIWU
Port G is an 8-bit port with 5 I/O pins (G0, G2–G5), an input pin (G6), and a dedicated output pin (G7). Pins G0 and G2–G6 all have Schmitt Triggers on their inputs. Pin G1 serves as the dedicated WDOUT WATCHDOG output, while pin G7 is either input or output depending on the oscillator mask option selected. With the crystal oscillator option se­lected, G7 serves as the dedicated output pin for the CKO clock output. With the single-pin R/C oscillator mask option selected, G7 serves as a general purpose input pin but is also used to bring the device out of HALTmode with a low to high transition on G7. There are two registers associated with the G Port, a data register and a configuration register. Therefore, each of the 5 I/O bits (G0, G2–G5) can be indi­vidually configured under software control.
Since G6 is an input only pin and G7 is the dedicated CKO clock output pin (crystal clock option) or general purpose in­put (R/C clock option), the associated bits in the data and
configuration registers for G6 and G7 are used for special purpose functions as outlined on the next page. Reading the G6 and G7 data bits will return zeros.
Note that the chip will be placed in the HALTmode by writing a “1” to bit 7 of the Port G Data Register. Similarly the chip will be placed in the IDLE mode by writing a “1” to bit 6 of the Port G Data Register.
Writing a “1” to bit 6 of the Port G Configuration Register en­ables the MICROWIRE/PLUS to operate with the alternate phase of the SK clock. The G7 configuration bit, if set high, enables the clock start up delay after HALT when the R/C clock configuration is used.
Config Reg. Data Reg.
G7 CLKDLY HALT G6 Alternate SK IDLE
Port G has the following alternate features:
G6 SI (MICROWIRE Serial Data Input) G5 SK (MICROWIRE Serial Clock) G4 SO (MICROWIRE Serial Data Output) G3 T1A (Timer T1 I/O) G2 T1B (Timer T1 Capture Input) G0 INTR (External Interrupt Input)
Port G has the following dedicated functions:
G7 CKO Oscillator dedicated output or general purpose
input
G1 WDOUT WATCHDOG and/or Clock Monitor dedi-
cated output
Port C is an 8-bit I/O port. The 40-pin device does not have a full complement of Port C pins. The unavailable pins are not terminated. A read operation for these unterminated pins will return unpredicatable values.
Port I is an 8-bit Hi-Z input port, and also provides the analog inputs to theA/D converter. The 28-pin device does not have a full complement of Port I pins. The unavailable pins are not terminated (i.e. they are floating). A read operation from these unterminated pins will return unpredictable values. The user should ensure that the software takes this into ac­count by either masking out these inputs, or else restricting the accesses to bit operations only. If unterminated, Port I pins will draw power only when addressed.
DS100076-5
FIGURE 4. I/O Port Configurations
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Page 12
Pin Descriptions (Continued)
Port D is an 8-bit output port that is preset high when RESET goes low. The user can tie two or more D port outputs (ex­cept D2) together in order to get a higher drive.
Note: Care must be exercised with the D2 pin operation. At RESET, the ex-
ternal loads on this pin must ensure that the output voltages stay above 0.8 V
CC
to prevent the chip from entering special modes. Also
keep the external loading on D2 to
<
1000 pF.
Functional Description
The architecture of the device is modified Harvard architec­ture. With the Harvard architecture, the control store pro­gram memory (ROM) is separated from the data store memory (RAM). Both ROM and RAM have their own sepa­rate addressing space with separate address buses. The ar­chitecture, though based on Harvard architecture, permits transfer of data from ROM to RAM.
CPU REGISTERS
The CPU can do an 8-bit addition, subtraction, logical or shift operation in one instruction (t
c
) cycle time. There are six CPU registers: A is the 8-bit Accumulator Register PC is the 15-bit Program Counter Register
PU is the upper 7 bits of the program counter (PC) PL is the lower 8 bits of the program counter (PC)
B is an 8-bit RAM address pointer, which can be optionally post auto incremented or decremented.
X is an 8-bit alternate RAM address pointer, which can be optionally post auto incremented or decremented.
SP is the 8-bit stack pointer, which points to the subroutine/ interrupt stack (in RAM). The SP is initialized to RAM ad­dress 06F with reset.
S is the 8-bit Data Segment Address Register used to extend the lower half of the address range (00 to 7F) into 256 data segments of 128 bytes each.
PROGRAM MEMORY
The program memory consists of 16 kbytes of ROM. These bytes may hold program instructions or constant data (data tables for the LAID instruction, jump vectors for the JID in­struction, and interrupt vectors for the VIS instruction). The program memory is addressed by the 15-bit program counter (PC). All interrupts in the devices vector to program memory location 0FF Hex.
DATA MEMORY
The data memory address space includes the on-chip RAM and data registers, the I/O registers (Configuration, Data and Pin), the control registers, the MICROWIRE/PLUS SIO shift register, and the various registers, and counters associated with the timers (with the exception of the IDLE timer). Data memory is addressed directly by the instruction or indirectly by the B, X, SP pointers and S register.
The data memory consists of 256 bytes of RAM. Sixteen bytes of RAM are mapped as “registers” at addresses 0F0 to 0FF Hex. These registers can be loaded immediately, and also decremented and tested with the DRSZ (decrement register and skip if zero) instruction. The memory pointer
registers X, SP, B and S are memory mapped into this space at address locations 0FC to 0FF Hex respectively, with the other registers being available for general usage.
The instruction set permits any bit in memory to be set, reset or tested. All I/O and registers (except A and PC) are memory mapped; therefore, I/O bits and register bits can be directly and individually set, reset and tested. The accumula­tor (A) bits can also be directly and individually tested.
Note: RAM contents are undefined upon power-up.
Data Memory Segment RAM Extension
Data memory address 0FF is used as a memory mapped lo­cation for the Data Segment Address Register (S).
The data store memory is either addressed directly by a single byte address within the instruction, or indirectly rela­tive to the reference of the B, X, or SP pointers (each con­tains a single-byte address). This single-byte address allows an addressing range of 256 locations from 00 to FF hex. The upper bit of this single-byte address divides the data store memory into two separate sections as outlined previously. With the exception of the RAM register memory from ad­dress locations 00F0 to 00FF, all RAM memory is memory mapped with the upper bit of the single-byte address being equal to zero. This allows the upper bit of the single-byte ad­dress to determine whether or not the base address range (from 0000 to 00FF) is extended. If this upper bit equals one (representing address range 0080 to 00FF), then address extension does not take place. Alternatively, if this upper bit equals zero, then the data segment extension register S is used to extend the base address range (from 0000 to 007F) from XX00 to XX7F, where XX represents the 8 bits from the S register. Thus the 128-byte data segment extensions are located from addresses 0100 to 017F for data segment 1, 0200 to 027F for data segment 2, etc., up to FF00 to FF7F for data segment 255. The base address range from 0000 to 007F represents data segment 0.
Figure 5
illustrates how the S register data memory exten­sion is used in extending the lower half of the base address range (00 to 7F hex) into 256 data segments of 128 bytes each, with a total addressing range of 32 kbytes from XX00 to XX7F. This organization allows a total of 256 data seg­ments of 128 bytes each with an additional upper base seg­ment of 128 bytes. Furthermore, all addressing modes are available for all data segments. The S register must be changed under program control to move from one data seg­ment (128 bytes) to another. However, the upper base seg­ment (containing the 16 memory registers, I/O registers, control registers, etc.) is always available regardless of the contents of the S register, since the upper base segment (address range 0080 to 00FF) is independent of data seg­ment extension.
The instructions that utilize the stack pointer (SP) always ref­erence the stack as part of the base segment (Segment 0), regardless of the contents of the S register. The S register is not changed by these instructions. Consequently, the stack (used with subroutine linkage and interrupts) is always lo­cated in the base segment. The stack pointer will be initial­ized to point at data memory location 006F as a result of reset.
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Data Memory Segment RAM Extension
(Continued)
The 128 bytes of RAM contained in the base segment are split between the lower and upper base segments. The first 112bytes of RAM are resident from address 0000 to 006F in the lower base segment, while the remaining 16 bytes of RAM represent the 16 data memory registers located at ad­dresses 00F0 to 00FF of the upper base segment. No RAM is located at the upper sixteen addresses (0070 to 007F) of the lower base segment.
Reset
The RESET input when pulled low initializes the microcon­troller. Initialization will occur whenever the RESET input is pulled low. Upon initialization, the data and configuration registers for ports L, G and C are cleared, resulting in these Ports being initialized to the TRI-STATEmode. Pin G1 of the G Port is an exception (as noted below) since pin G1 is dedi­cated as the WATCHDOGand/or Clock Monitor error output pin. Port D is set high. The PC, PSW, ICNTRL, CNTRL, T2CNTRL and T3CNTRL control registers are cleared. The Comparator Select Register is cleared. The S register is ini­tialized to zero. The Multi-Input Wakeup registers WKEN and WKEDG are cleared. Wakeup register WKPND is unknown. The stack pointer, SP, is initialized to 6F hex.
The device comes out of reset with both the WATCHDOG logic and the Clock Monitor detector armed, with the WATCHDOG service window bits set and the Clock Monitor bit set. The WATCHDOG and Clock Monitor circuits are in­hibited during reset. The WATCHDOG service window bits being initialized high default to the maximum WATCHDOG service window of 64k t
C
clock cycles. The Clock Monitor bit being initialized high will cause a Clock Monitor error follow­ing reset if the clock has not reached the minimum specified frequency at the termination of reset. A Clock Monitor error will cause an active low error output on pin G1. This error
output will continue until 16 t
C
–32 tCclock cycles following the clock frequency reaching the minimum specified value, at which time the G1 output will enter the TRI-STATE mode.
The external RC network shown in
Figure 6
should be used to ensure that the RESET pin is held low until the power sup­ply to the chip stabilizes.
Oscillator Circuits
The chip can be driven by a clock input on the CKI input pin which can be between DC and 10 MHz. The CKO output clock is on pin G7 (crystal configuration). The CKI input fre­quency is divided down by 10 to produce the instruction cycle clock (1/t
c
).
Note: External clocks with frequencies above about 4 MHz require the user
to drive the CKO (G7) pin with a signal 180 degrees out of phase with CKI.
Figure 7
shows the Crystal and R/C oscillator diagrams.
CRYSTAL OSCILLATOR
CKI and CKO can be connected to make a closed loop crys­tal (or resonator) controlled oscillator.
Table 1
shows the component values required for various
standard crystal values.
R/C OSCILLATOR
By selecting CKI as a single pin oscillator input, a single pin R/C oscillator circuit can be connected to it. CKO is available as a general purpose input, and/or HALT restart input.
Note: Use of the R/C oscillator option will result in higher electromagnetic
emissions.
Table 1
shows the variation in the oscillator frequencies as
functions of the component (R and C) values.
DS100076-6
*
Reads as all ones.
FIGURE 5. RAM Organization
DS100076-7
RC>5 x Power Supply Rise Time
FIGURE 6. Recommended Reset Circuit
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Oscillator Circuits (Continued)
TABLE 1. Crystal Oscillator Configuration, T
A
=
25˚C
R1 R2 C1 C2 CKI Freq Conditions
(kΩ)(MΩ) (pF) (pF) (MHz)
0 1 30 30–36 10 V
CC
=
5V
0 1 30 30–36 4 V
CC
=
5V
0 1 200 100–150 0.455 V
CC
=
5V
TABLE 2. RC Oscillator Configuration, T
A
=
25˚C
R C CKI Freq Instr. Cycle Conditions
(kΩ) (pF) (MHz) (µs)
3.3 82 2.2 to 2.7 3.7 to 4.6 V
CC
=
5V
5.6 100 1.1 to 1.3 7.4 to 9.0 V
CC
=
5V
6.8 100 0.9 to 1.1 8.8 to 10.8 V
CC
=
5V
Note 31: 3k ≤ R ≤ 200k
50 pF ≤ C ≤ 200 pF
CONTROL REGISTERS
CNTRL Register (Address X'00EE)
T1C3 T1C2 T1C1 T1C0 MSEL IEDG SL1 SL0
Bit 7 Bit 0
The Timer1 (T1) and MICROWIRE/PLUS control register contains the following bits:
T1C3 Timer T1 mode control bit T1C2 Timer T1 mode control bit T1C1 Timer T1 mode control bit T1C0 Timer T1 Start/Stop control in timer
modes 1 and 2, T1 Underflow Interrupt Pending Flag in timer mode 3
MSEL Selects G5 and G4 as MICROWIRE/PLUS
signals SK and SO respectively
IEDG External interrupt edge polarity select
(0 = Rising edge, 1 = Falling edge)
SL1 & SL0 Select the MICROWIRE/PLUS clock divide
by (00 = 2, 01 = 4, 1x = 8)
PSW Register (Address X'00EF)
HC C T1PNDA T1ENA EXPND BUSY EXEN GIE
Bit 7 Bit 0
The PSW register contains the following select bits:
HC Half Carry Flag C Carry Flag T1PNDA Timer T1 Interrupt Pending Flag (Autoreload
RA in mode 1, T1 Underflow in Mode 2, T1A capture edge in mode 3)
T1ENA Timer T1 Interrupt Enable for Timer Underflow
or T1A Input capture edge EXPND External interrupt pending BUSY MICROWIRE/PLUS busy shifting flag EXEN Enable external interrupt GIE Global interrupt enable (enables interrupts)
ICNTRL Register (Address X'00E8)
Reserved LPEN T0PND T0EN µWPND µWEN T1PNDB T1ENB Bit 7 Bit 0
The ICNTRL register contains the following bits:
Reserved This bit is reserved and should to zero LPEN L Port Interrupt Enable (Multi-Input Wakeup/
Interrupt) T0PND Timer T0 Interrupt pending T0EN Timer T0 Interrupt Enable (Bit 12 toggle) µWPND MICROWIRE/PLUS interrupt pending µWEN Enable MICROWIRE/PLUS interrupt T1PNDB Timer T1 Interrupt Pending Flag for T1B cap-
ture edge T1ENB Timer T1 Interrupt Enable for T1B Input cap-
ture edge
T2CNTRL Register (Address X'00C6)
T2C3 T2C2 T2C1 T2C0 T2PNDA T2ENA T2PNDB T2ENB Bit 7 Bit 0
The T2CNTRL control register contains the following bits:
T2C3 Timer T2 mode control bit T2C2 Timer T2 mode control bit T2C1 Timer T2 mode control bit T2C0 Timer T2 Start/Stop control in timer
modes 1 and 2, T2 Underflow Interrupt Pend-
ing Flag in timer mode 3 T2PNDA Timer T2 Interrupt Pending Flag (Autoreload
RA in mode 1, T2 Underflow in mode 2, T2A
capture edge in mode 3) T2ENA Timer T2 Interrupt Enable for Timer Underflow
or T2A Input capture edge T2PNDB Timer T2 Interrupt Pending Flag for T2B cap-
ture edge
DS100076-8
DS100076-9
FIGURE 7. Crystal and R/C Oscillator Diagrams
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CONTROL REGISTERS (Continued)
T2ENB Timer T2 Interrupt Enable for Timer Underflow
or T2B Input capture edge
T3CNTRL Register (Address X'00B6)
T3C3 T3C2 T3C1 T3C0 T3PNDA T3ENA T3PNDB T3ENB Bit 7 Bit 0
The T3CNTRL control register contains the following bits:
T3C3 Timer T3 mode control bit T3C2 Timer T3 mode control bit T3C1 Timer T3 mode control bit T3C0 Timer T3 Start/Stop control in timer
modes 1 and 2, T3 Underflow Interrupt Pend­ing Flag in timer mode 3
T3PNDA Timer T3 Interrupt Pending Flag (Autoreload
RA in mode 1, T3 Underflow in mode 2, T3A capture edge in mode 3)
T3ENA Timer T3 Interrupt Enable for Timer Underflow
or T3A Input capture edge
T3PNDB Timer T3 Interrupt Pending Flag for T3B cap-
ture edge
T3ENB Timer T3 Interrupt Enable for Timer Underflow
or T3B Input capture edge
Timers
The device contains a very versatile set of timers (T0, T1, T2, T3). All timers and associated autoreload/capture regis­ters power up containing random data.
TIMER T0 (IDLE TIMER)
The device supports applications that require maintaining real time and low power with the IDLE mode. This IDLE mode support is furnished by the IDLE timer T0, which is a 16-bit timer. The Timer T0 runs continuously at the fixed rate of the instruction cycle clock, t
c
. The user cannot read or
write to the IDLE Timer T0, which is a count down timer. The Timer T0 supports the following functions:
j
Exit out of the Idle Mode (See Idle Mode description)
j
WATCHDOG logic (See WATCHDOG description)
j
Start up delay out of the HALT mode
Figure 8
is a functional block diagram showing the structure
of the IDLE Timer and its associated interrupt logic.
In order for an interrupt to be generated, the IDLE Timer in­terrupt enable bit T0EN must be set, and the GIE (Global In­terrupt Enable) bit must also be set. The T0PND flag and T0EN bit are bits 5 and 4 of the ICNTRL register, respec­tively.The interrupt can be used for any purpose. Typically, it is used to perform a task upon exit from the IDLE mode. For more information on the IDLE mode, refer to the Power Save Modes section.
TABLE 3. Idle Timer Window Length
ITSEL2 ITSEL1 ITSEL0 Idle Timer Period
(Instruction Cycles)
0 0 0 4,096 0 0 1 8,192 0 1 0 16,384 0 1 1 32,768 1 X X 65,536
The ITMR is cleared on Reset and the Idle Timer period is re­set to 4,096 instruction cycles.
ITMR Register (Address X’0xCF)
Reserved ITSEL2 ITSEL1 ITSEL0
Bit 7 Bit 0
Any time the IDLE Timer period is changed there is the pos­sibility of generating a spurious IDLE Timer interrupt by set­ting the T0PND bit. The user is advised to disable IDLE Timer interrupts prior to changing the value of the ITSEL bits of the ITMR Register and then clear the T0PND bit before at­tempting to synchronize operation to the IDLE Timer.
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Timers (Continued)
TIMER T1, TIMER T2 AND TIMER T3
The device has a set of three powerful timer/counter blocks, T1, T2 and T3. The associated features and functioning of a timer block are described by referring to the timer block Tx. Since the three timer blocks, T1, T2 and T3 are identical, all comments are equally applicable to any of the three timer blocks.
Each timer block consists of a 16-bit timer, Tx, and two sup­porting 16-bit autoreload/capture registers, RxA and RxB. Each timer block has two pins associated with it, TxA and TxB. The pin TxA supports I/O required by the timer block, while the pin TxB is an input to the timer block. The powerful and flexible timer block allows the device to easily perform all timer functions with minimal software overhead. The timer block has three operating modes: Processor Independent PWM mode, External Event Counter mode, and Input Cap­ture mode.
The control bits TxC3, TxC2, and TxC1 allow selection of the different modes of operation.
Mode 1. Processor Independent PWM Mode
As the name suggests, this mode allows the device to gen­erate a PWM signal with very minimal user intervention. The user only has to define the parameters of the PWM signal (ON time and OFF time). Once begun, the timer block will continuously generate the PWM signal completely indepen­dent of the microcontroller. The user software services the timer block only when the PWM parameters require updat­ing.
In this mode the timer Tx counts down at a fixed rate of t
c
. Upon every underflow the timer is alternately reloaded with the contents of supporting registers, RxA and RxB. The very first underflow of the timer causes the timer to reload from
the register RxA. Subsequent underflows cause the timer to be reloaded from the registers alternately beginning with the register RxB.
The Tx Timer control bits, TxC3, TxC2 and TxC1 set up the timer for PWM mode operation.
Figure 9
shows a block diagram of the timer in PWM mode.
The underflows can be programmed to toggle the TxA output pin. The underflows can also be programmed to generate in­terrupts.
Underflows from the timer are alternately latched into two pending flags, TxPNDA and TxPNDB. The user must reset these pending flags under software control. Two control en­able flags, TxENA and TxENB, allow the interrupts from the timer underflow to be enabled or disabled. Setting the timer enable flag TxENA will cause an interrupt when a timer un­derflow causes the RxAregister to be reloaded into the timer. Setting the timer enable flag TxENB will cause an interrupt when a timer underflow causes the RxB register to be re­loaded into the timer. Resetting the timer enable flags will disable the associated interrupts.
Either or both of the timer underflow interrupts may be en­abled. This gives the user the flexibility of interrupting once per PWM period on either the rising or falling edge of the PWM output. Alternatively, the user may choose to interrupt on both edges of the PWM output.
DS100076-17
FIGURE 8. Functional Block Diagram for Idle Timer T0
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Timers (Continued)
Mode 2. External Event Counter Mode
This mode is quite similar to the processor independent PWM mode described above. The main difference is that the timer,Tx, is clocked by the input signal from the TxA pin. The Tx timer control bits, TxC3, TxC2 and TxC1 allow the timer to be clocked either on a positive or negative edge from the TxA pin. Underflows from the timer are latched into the TxP­NDA pending flag. Setting the TxENA control flag will cause an interrupt when the timer underflows.
In this mode the input pin TxB can be used as an indepen­dent positive edge sensitive interrupt input if the TxENB con­trol flag is set. The occurrence of a positive edge on the TxB input pin is latched into the TxPNDB flag.
Figure 10
shows a block diagram of the timer in External
Event Counter mode.
Note: The PWM output is not available in this mode since the TxA pin is being
used as the counter input clock.
Mode 3. Input Capture Mode
In this mode, the timer Tx is constantly running at the fixed t
c
rate. The two registers, RxA and RxB, act as capture regis­ters. Each register acts in conjunction with a pin. The register RxAacts in conjunction with the TxApin and the register RxB acts in conjunction with the TxB pin.
The timer value gets copied over into the register when a trigger event occurs on its corresponding pin. Control bits,
TxC3, TxC2 and TxC1, allow the trigger events to be speci­fied either as a positive or a negative edge. The trigger con­dition for each input pin can be specified independently.
The trigger conditions can also be programmed to generate interrupts. The occurrence of the specified trigger condition on the TxA and TxB pins will be respectively latched into the pending flags, TxPNDA and TxPNDB. The control flag Tx­ENA allows the interrupt on TxA to be either enabled or dis­abled. Setting the TxENA flag enables interrupts to be gener­ated when the selected trigger condition occurs on the TxA pin. Similarly, the flag TxENB controls the interrupts from the TxB pin.
Underflows from the timer can also be programmed to gen­erate interrupts. Underflows are latched into the timer TxC0 pending flag (the TxC0 control bit serves as the timer under­flow interrupt pending flag in the Input Capture mode). Con­sequently, the TxC0 control bit should be reset when enter­ing the Input Capture mode. The timer underflow interrupt is enabled with the TxENA control flag. When a TxA interrupt occurs in the Input Capture mode, the user must check both the TxPNDA and TxC0 pending flags in order to determine whether a TxA input capture or a timer underflow (or both) caused the interrupt.
Figure 11
shows a block diagram of the timer in Input Cap-
ture mode.
TIMER CONTROL FLAGS
The control bits and their functions are summarized below.
TxC3 Timer mode control TxC2 Timer mode control TxC1 Timer mode control TxC0 Timer Start/Stop control in Modes 1 and 2 (Pro-
cessor Independent PWM and External Event Counter), where 1 = Start, 0 = Stop
Timer Underflow Interrupt Pending Flag in
Mode 3 (Input Capture) TxPNDA Timer Interrupt Pending Flag TxENA Timer Interrupt Enable Flag
1 = Timer Interrupt Enabled
0 = Timer Interrupt Disabled TxPNDB Timer Interrupt Pending Flag TxENB Timer Interrupt Enable Flag
1 = Timer Interrupt Enabled
0 = Timer Interrupt Disabled
DS100076-10
FIGURE 9. Timer in PWM Mode
DS100076-11
FIGURE 10. Timer in External Event Counter Mode
DS100076-12
FIGURE 11. Timer in Input Capture Mode
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Timers (Continued)
The timer mode control bits (TxC3, TxC2 and TxC1) are detailed below:
Mode TxC3 TxC2 TxC1 Description
Interrupt A
Source
Interrupt B
Source
Timer
Counts On
1
1 0 1 PWM: TxA Toggle Autoreload RA Autoreload RB t
C
1 0 0 PWM: No TxA
Toggle
Autoreload RA Autoreload RB
t
C
2
0 0 0 External Event
Counter
Timer Underflow
Pos. TxB Edge Pos. TxA
Edge
0 0 1 External Event
Counter
Timer Underflow
Pos. TxB Edge Pos. TxA
Edge
3
0 1 0 Captures: Pos. TxA Edge Pos. TxB Edge t
C
TxA Pos. Edge or Timer TxB Pos. Edge Underflow
1 1 0 Captures: Pos. TxA Neg. TxB t
C
TxA Pos. Edge Edge or Timer Edge TxB Neg. Edge Underflow
0 1 1 Captures: Neg. TxA Neg. TxB t
C
TxA Neg. Edge Edge or Timer Edge TxB Neg. Edge Underflow
1 1 1 Captures: Neg. TxA Neg. TxB t
C
TxA Neg. Edge Edge or Timer Edge TxB Neg. Edge Underflow
Power Save Modes
HALT MODE
The device can be placed in the HALTmode by writing a “1” to the HALT flag (G7 data bit). All microcontroller activities, including the clock and timers, are stopped. The WATCH­DOG logic is disabled during the HALT mode. However, the clock monitor circuitry if enabled remains active and will cause the WATCHDOG output pin (WDOUT) to go low. If the HALT mode is used and the user does not want to activate the WDOUT pin, the Clock Monitor should be disabled after the device comes out of reset (resetting the Clock Monitor control bit with the first write to the WDSVR register). In the HALTmode, the power requirements of the device are mini­mal and the applied voltage (V
CC
) may be decreased to V
r
(V
r
=
2.0V) without altering the state of the machine.
The device supports three different ways of exiting the HALT mode. The first method of exiting the HALTmode is with the Multi-Input Wakeup feature on the L port. The second method is with a low to high transition on the CKO (G7) pin. This method precludes the use of the crystal clock configura­tion (since CKO becomes a dedicated output), and so may be used with an RC clock configuration. The third method of exiting the HALT mode is by pulling the RESET pin low.
Since a crystal or ceramic resonator may be selected as the oscillator, the Wakeup signal is not allowed to start the chip running immediately since crystal oscillators and ceramic
resonators have a delayed start up time to reach full ampli­tude and frequency stability. The IDLE timer is used to gen­erate a fixed delay to ensure that the oscillator has indeed stabilized before allowing instruction execution. In this case, upon detecting a valid Wakeup signal, only the oscillator cir­cuitry is enabled. The IDLE timer is loaded with a value of 256 and is clocked with the t
c
instruction cycle clock. The t
c
clock is derived by dividing the oscillator clock down by a fac­tor of 10. The Schmitt trigger following the CKI inverter on the chip ensures that the IDLE timer is clocked only when the oscillator has a sufficiently large amplitude to meet the Schmitt trigger specifications. This Schmitt trigger is not part of the oscillator closed loop. The startup timeout from the IDLE timer enables the clock signals to be routed to the rest of the chip.
If an RC clock option is being used, the fixed delay is intro­duced optionally. A control bit, CLKDLY, mapped as configu­ration bit G7, controls whether the delay is to be introduced or not. The delay is included if CLKDLYis set, and excluded if CLKDLY is reset. The CLKDLY bit is cleared on reset.
The device has two mask options associated with the HALT mode. The first mask option enables the HALTmode feature, while the second mask option disables the HALTmode. With the HALT mode enable mask option, the device will enter and exit the HALTmode as described above. With the HALT disable mask option, the device cannot be placed in the HALTmode (writing a “1” to the HALT flag will have no effect, the HALT flag will remain “0”).
The WATCHDOG detector circuit is inhibited during the HALTmode. However,the clock monitor circuit if enabled re­mains active during HALT mode in order to ensure a clock monitor error if the device inadvertently enters the HALT mode as a result of a runaway program or power glitch.
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Power Save Modes (Continued)
IDLE MODE
The device is placed in the IDLE mode by writing a “1” to the IDLE flag (G6 data bit). In this mode, all activities, except the associated on-board oscillator circuitry, the WATCHDOG logic, the clock monitor and the IDLE Timer T0, are stopped. The power supply requirements of the microcontroller in this mode of operation are typically around 30%of normal power requirement of the microcontroller.
As with the HALT mode, the device can be returned to nor­mal operation with a reset, or with a Multi-Input Wakeup from the L Port.
The microcontroller may also be awakened from the IDLE mode after a selectable amount of time up to 65,536 instruc­tion cycles, or 65.536 milliseconds with a 1 MHz instruction clock frequency.
The user has the option of being interrupted with a transition on the thirteenth bit of the IDLE Timer T0. The interrupt can be enabled or disabled via the T0EN control bit. Setting the T0EN flag enables the interrupt and vice versa.
The user can enter the IDLE mode with the Timer T0 inter­rupt enabled. In this case, when the T0PND bit gets set, the device will first execute the TimerT0 interrupt service routine and then return to the instruction following the “Enter Idle Mode” instruction.
Alternatively, the user can enter the IDLE mode with the IDLE Timer T0 interrupt disabled. In this case, the device will resume normal operation with the instruction immediately following the “Enter IDLE Mode” instruction.
The IDLE timer cannot be started or stopped under software control, and it is not memory mapped, so it cannot be read or written by the software. Its state upon Reset is unknown. Therefore, if the device is put into the IDLE mode at an arbi­trary time, it will stay in the IDLE mode for somewhere be­tween 1 and the selected number of instruction cycles.
Note: It is necessary to program two NOP instructions following both the set
HALT mode and set IDLE mode instructions. These NOP instructions are necessary to allow clock resynchronization following the HALT or IDLE modes.
For more information on the IDLE Timer and its associated interrupt, see the description in the Timers Section.
Multi-Input Wakeup
The Multi-Input Wakeup feature is ued to return (wakeup) the device from either the HALT or IDLE modes. Alternately Multi-Input Wakeup/Interrupt feature may also be used to generate up to 8 edge selectable external interrupts.
Figure 12
shows the Multi-Input Wakeup logic.
The Multi-Input Wakeup feature utilizes the L Port. The user selects which particular L port bit (or combination of L Port bits) will cause the device to exit the HALT or IDLE modes. The selection is done through the Reg: WKEN. The Reg: WKEN is an 8-bit read/write register, which contains a con­trol bit for every L port bit. Setting a particular WKEN bit en­ables a Wakeup from the associated L port pin.
The user can select whether the trigger condition on the se­lected L Port pin is going to be either a positive edge (low to high transition) or a negative edge (high to low transition). This selection is made via the Reg: WKEDG, which is an 8-bit control register with a bit assigned to each L Port pin. Setting the control bit will select the trigger condition to be a negative edge on that particular L Port pin. Resetting the bit
DS100076-13
FIGURE 12. Multi-Input Wake Up Logic
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Page 20
Multi-Input Wakeup (Continued)
selects the trigger condition to be a positive edge. Changing an edge select entails several steps in order to avoid a pseudo Wakeup condition as a result of the edge change. First, the associated WKEN bit should be reset, followed by the edge select change in WKEDG. Next, the associated WKPND bit should be cleared, followed by the associated WKEN bit being re-enabled.
An example may serve to clarify this procedure. Suppose we wish to change the edge select from positive (low going high) to negative (high going low) for L Port bit 5, where bit 5 has previously been enabled for an input interrupt. The program would be as follows:
RBIT 5, WKEN ; Disable MIWU SBIT 5, WKEDG ; Change edge polarity RBIT 5, WKPND ; Reset pending flag SBIT 5, WKEN ; Enable MIWU
If the L port bits have been used as outputs and then changed to inputs with Multi-Input Wakeup/Interrupt, a safety procedure should also be followed to avoid inherited pseudo wakeup conditions. After the selected L port bits have been changed from output to input but before the associated WKEN bits are enabled, the associated edge select bits in WKEDG should be set or reset for the desired edge selects, followed by the associated WKPND bits being cleared.
The occurrence of the selected trigger condition for Multi-Input Wakeup is latched into a pending register called WKPND. The respective bits of the WKPND register will be set on the occurrence of the selected trigger edge on the cor­responding Port L pin. The user has the responsibility of clearing these pending flags. Since WKPND is a pending register for the occurrence of selected wakeup conditions, the device will not enter the HALTmode if any Wakeup bit is both enabled and pending. Consequently, the user has the responsibility of clearing the pending flags before attempting to enter the HALT mode.
WKEN, WKPND and WKEDG are all read/write registers, and are cleared at reset.
PORT L INTERRUPTS
Port L provides the user with an additional eight fully select­able, edge sensitive interrupts which are all vectored into the same service subroutine.
The GIE (Global Interrupt Enable) bit enables the interrupt function.
A control flag, LPEN, functions as a global interrupt enable for Port L interrupts. Setting the LPEN flag will enable inter­rupts and vice versa. A separate global pending flag is not needed since the register WKPND is adequate.
modes. In the other case, the device will first execute the in­terrupt service routine and then revert to normal operation. (See HALT MODE for clock option wakeup information.)
A/D Converter
The device contains an 8-channel, multiplexed input, suc­cessive approximation, Analog-to Digital converter. The de­vice’s VCC and GND pins are used for voltage reference.
OPERATING MODES
The A/D converter supports ratiometric measurements. It supports both Single Ended and Differential modes of opera­tion.
Four specific analog channel selection modes are sup­ported. These are as follows:
Allow any specific channel to be selected at one time. The A/D converter performs the specific conversion requested and stops.
Allow any specific channel to be scanned continuously. In other words, the user specifies the channel and the A/D con­verter scans it continuously. At any arbitrary time the user can immediately read the result of the last conversion. The user must wait for only the first conversion to complete.
Allow any differential channel pair to be selected at one time. The A/D converter performs the specific differential conver­sion requested and stops.
Allow any differential channel pair to be scanned continu­ously.In other words, the user specifies the differential chan­nel pair and the A/D converter scans it continuously. At any arbitrary time the user can immediately read the result of the last differential conversion. The user must wait for only the first conversion to complete.
TheA/D converter is supported by two memory mapped reg­isters, the result register and the mode control register. When the device is reset, the mode control register (ENAD) is cleared, the A/D is powered down and the A/D result reg­ister has unknown data.
A/D Control Register
The ENAD control register contains 3 bits for channel selec­tion, 2 bits for prescaler selection, 2 bits for mode selection and a Busy bit. An A/D conversion is initiated by setting the ADBSY bit in the ENAD control register. The result of the conversion is available to the user in the A/D result register, ADRSLT, when ADBSY is cleared by the hardware on completion of the conversion.
ENAD (Address 0xCB)
CHANNEL MODE PRESCALER BUSY
SELECT SELECT SELECT
ADCH2 ADCH1 ADCH0 ADMOD1 ADMOD0 PSC1 PSC0 ADBSY
Bit 7 Bit 0
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A/D Converter (Continued)
CHANNEL SELECT This 3-bit field selects one of eight channels to be the V
IN+
.
The mode selection determines the V
IN−
input.
Single Ended mode:
Bit 7 Bit 6 Bit 5 Channel No.
000 0 001 1 010 2 011 3 100 4 101 5 110 6 111 7
Differential mode:
Bit 7 Bit 6 Bit 5 Channel Pairs (+, −)
000 0,1 001 1,0 010 2,3 011 3,2 100 4,5 101 5,4 110 6,7
111 7,6 MODE SELECT This 2-bit field is used to select the mode of operation (single
conversion, continuous conversions, differential, single ended) as shown in the following table.
Bit 4 Bit 3 Mode
0 0 Single Ended mode, single
conversion
0 1 Single Ended mode, continuous scan
of a single channel into the result
register 1 0 Differential mode, single conversion 1 1 Differential mode, continuous scan of
a channel pair into the result register
PRESCALER SELECT This 2-bit field is used to select one of the four prescaler
clocks for the A/D converter. The following table shows the various prescaler options.
A/D Converter Clock Prescale
Bit 2 Bit 1 Clock Select
0 0 Divide by 2 0 1 Divide by 4 1 0 Divide by 6 1 1 Divide by 12
BUSY BIT
The ADBSY bit of the ENAD register is used to control start­ing and stopping of the A/D conversion. When ADBSY is cleared, the prescale logic is disabled and the A/D clock is turned off. Setting theADBSY bit starts the A/D clock and ini­tiates a conversion based on the mode select value currently in the ENAD register. Normal completion of an A/D conver­sion clears the ADBSY bit and turns off the A/D converter.
TheADBSY bit remains a one during continuous conversion. The user can stop continuous conversion by writing a zero to the ADBSY bit.
If the user wishes to restart a conversion which is already in progress, this can be accomplished only by writing a zero to the ADBSY bit to stop the current conversion and then by writing a one to ADBSY to start a new conversion. This can be done in two consecutive instructions.
ADC Operation
The A/D converter interface works as follows. Setting the ADBSY bit in the A/D control register ENAD initiates an A/D conversion. The conversion sequence starts at the begin­ning of the write to ENAD operation which sets ADBSY, thus powering up the A/D. At the first falling edge of the converter clock following the write operation, the sample signal turns on for seven clock cycles. If the A/D is in single conversion mode, the conversion complete signal from the A/D will gen­erate a power down for the A/D converter and will clear the ADBSY bit in the ENAD register at the next instruction cycle boundary. If the A/D is in continuous mode, the conversion complete signal will restart the conversion sequence by de­selecting the A/D for one converter clock cycle before start­ing the next sample. The A/D 8-bit result is immediately loaded into the A/D result register (ADRSLT) upon comple­tion. Internal logic prevents transient data (resulting from the A/D writing a new result over an old one) being read from ADRSLT.
Inadvertent changes to the ENAD register during conversion are prevented by the control logic of the A/D. Any attempt to write any bit of the ENAD Register except ADBSY, while ADBSY is a one, is ignored. ADBSY must be cleared either by completion of an A/D conversion or by the user before the prescaler, conversion mode or channel select values can be changed.After stopping the current conversion, the user can load different values for the prescaler, conversion mode or channel select and start a new conversion in one instruction.
It is important for the user to realize that, when used in differ­ential mode, only the positive input to the A/D converter is sampled and held. The negative input is constantly con­nected and should be held stable for the duration of the con­version. Failure to maintain a stable negative input will result in incorrect conversion.
PRESCALER
The A/D Converter (A/D) contains a prescaler option that al­lows four different clock selections. The A/D clock frequency is equal to CKI divided by the prescaler value. Note that the prescaler value must be chosen such that the A/D clock falls within the specified range. The maximum A/D frequency is
1.67 MHz. This equates to a 600 ns A/D clock cycle.
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A/D Converter (Continued)
The A/D converter takes 17 A/D clock cycles to complete a conversion. Thus the minimum A/D conversion time for the device is 10.2 µs when a prescaler of 6 has been selected. The 17 A/D clock cycles needed for conversion consist of 1 cycle at the beginning for reset, 7 cycles for sampling, 8 cycles for converting, and 1 cycle for loading the result into theA/D result register (ADRSLT). This A/D result register is a read-only register. The user cannot write into ADRSLT.
TheADBSY flag provides an A/D clock inhibit function, which saves power by powering down the A/D when it is not in use.
Note: The A/D converter is also powered down when the device is in either
the HALTor IDLE modes. If the A/D is running when the device enters the HALT or IDLE modes, the A/D powers down and then restarts the conversion with a corrupted sampled voltage (and thus an invalid re­sult) when the device comes out of the HALT or IDLE modes.
Analog Input and Source Resistance Considerations
Figure 13
shows the A/D pin model in single ended mode. The differential mode has a similar A/D pin model. The leads to the analog inputs should be kept as short as possible. Both noise and digital clock coupling to an A/D input can
cause conversion errors. The clock lead should be kept away from the analog input line to reduce coupling. The A/D channel input pins do not have any internal output driver cir­cuitry connected to them because this circuitry would load the analog input signals due to output buffer leakage current.
Source impedances greater than 3 kΩ on the analog input lines will adversely affect the internal RC charging time dur­ing input sampling.As shown in
Figure 13
, the analog switch to the DAC array is closed only during the 7 A/D cycle sample time. Large source impedances on the analog inputs may result in the DAC array not being charged to the correct voltage levels, causing scale errors.
If large source resistance is necessary, the recommended solution is to slow down the A/D clock speed in proportion to the source resistance. The A/D converter may be operated at the maximum speed for R
S
less than 3 kΩ. For RSgreater than 3 kΩ, A/D clock speed needs to be reduced. For ex­ample, with R
S
=
6kΩ, the A/D converter may be operated at half the maximum speed. A/D converter clock speed may be slowed down by either increasing the A/D prescaler divide-by or decreasing the CKI clock frquency. The A/D minimum clock speed is 100 kHz.
Interrupts
INTRODUCTION
Each device supports eleven vectored interrupts. Interrupt sources include Timer 0, Timer 1, Timer 2, Timer 3, Port L Wakeup, Software Trap, MICROWIRE/PLUS, and External Input.
All interrupts force a branch to location 00FF Hex in program memory. The VIS instruction may be used to vector to the appropriate service routine from location 00FF Hex.
The Software trap has the highest priority while the default VIS has the lowest priority.
Each of the 11 maskable inputs has a fixed arbitration rank­ing and vector.
Figure 14
shows the Interrupt Block Diagram.
DS100076-18
*
The analog switch is closed only during the sample time.
FIGURE 13. A/D Pin Model (Single Ended Mode)
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Interrupts (Continued)
MASKABLE INTERRUPTS
Amaskable interrupt condition triggers an interrupt under the following conditions:
1. The enable bit associated with that interrupt is set.
2. The GIE bit is set.
3. The device is not processing a non-maskable interrupt. (If a non-maskable interrupt is being serviced, a maskable interrupt must wait until that service routine is completed.)
An interrupt is triggered only when all of these conditions are met at the beginning of an instruction. If different maskable interrupts meet these conditions simultaneously, the highest priority interrupt will be serviced first, and the other pending interrupts must wait.
An interrupt is an asychronous event which may occur be­fore, during, or after an instruction cycle. Any interrupt which occurs during the execution of an instruction is not acknowl-
edged until the start of the next normally executed instruction is to be skipped, the skip is performed before the pending in­terrupt is acknowledged.
At the start of interrupt acknowledgment, the following ac­tions occur:
2. The address of the instruction about to be executed is pushed onto the stack.
3. The program counter (PC) is loaded with 00FF Hex, causing a jump to that program memory location.
The device requires seven instruction cycles to perform the actions listed above.
If the user wishes to allow nested interrupts, the interrupts service routine may set the GIE bit to 1 by writing to the PSW register,and thus allow other maskable interrupts to interrupt the current service routine. If nested interrupts are allowed, caution must be exercised. The user must write the program in such a way as to prevent stack overflow, loss of saved context information, and other unwanted conditions.
The interrupt service routine stored at location 00FF Hex should use the VIS instruction to determine the cause of the interrupt, and jump to the interrupt handling routine corre­sponding to the highest priority enabled and active interrupt. Alternately, the user may choose to poll all interrupt pending and enable bits to determine the source(s) of the interrupt. If more than one interrupt is active, the user’s program must decide which interrupt to service.
Within a specific interrupt service routine, the associated pending bit should be cleared. This is typically done as early as possible in the service routine in order to avoid missing the next occurrence of the same type of interrupt event. Thus, if the same event occurs a second time, even while the first occurrence is still being serviced, the second occur­rence will be serviced immediately upon return from the cur­rent interrupt routine.
DS100076-14
FIGURE 14. Interrupt Block Diagram
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Interrupts (Continued)
An interrupt service routine typically ends with an RETI in­struction. This instruction sets the GIE bit back to 1, pops the address stored on the stack, and restores that address to the program counter. Program execution then proceeds with the next instruction that would have been executed had there been no interrupt. If there are any valid interrupts pending, the highest-priority interrupt is serviced immediately upon re­turn from the previous interrupt.
VIS INSTRUCTION
The general interrupt service routine, which starts at address 00FF Hex, must be capable of handling all types of inter­rupts. The VIS instruction, together with an interrupt vector table, directs the device to the specific interrupt handling rou­tine based on the cause of the interrupt.
VIS is a single-byte instruction, typically used at the very be­ginning of the general interrupt service routine at address 00FF Hex, or shortly after that point, just after the code used for context switching. The VIS instruction determines which enabled and pending interrupt has the highest priority, and causes an indirect jump to the address corresponding to that interrupt source. The jump addresses (vectors) for all pos­sible interrupts sources are stored in a vector table.
The vector table may be as long as 32 bytes (maximum of 16 vectors) and resides at the top of the 256-byte block contain­ing the VIS instruction. However, if the VIS instruction is at the very top of a 256-byte block (such as at 00FF Hex), the vector table resides at the top of the next 256-byte block. Thus, if the VIS instruction is located somewhere between 00FF and 01DF Hex (the usual case), the vector table is lo­cated between addresses 01E0 and 01FF Hex. If the VIS in­struction is located between 01FF and 02DF Hex, then the vector table is located between addresses 02E0 and 02FF Hex, and so on.
Each vector is 15 bits long and points to the beginning of a specific interrupt service routine somewhere in the 32 kbyte memory space. Each vector occupies two bytes of the vector table, with the higher-order byte at the lower address. The vectors are arranged in order of interrupt priority. The vector of the maskable interrupt with the lowest rank is located to 0yE0 (higher-order byte) and 0yE1 (lower-order byte). The next priority interrupt is located at 0yE2 and 0yE3, and so forth in increasing rank. The Software Trap has the highest rank and its vector is always located at 0yFE and 0yFF. The number of interrupts which can become active defines the size of the table.
Table4
shows the types of interrupts, the interrupt arbitration ranking, and the locations of the corresponding vectors in the vector table.
The vector table should be filled by the user with the memory locations of the specific interrupt service routines. For ex­ample, if the Software Trap routine is located at 0310 Hex, then the vector location 0yFE and -0yFF should contain the data 03 and 10 Hex, respectively. When a Software Trap in­terrupt occurs and the VIS instruction is executed, the pro­gram jumps to the address specified in the vector table.
The interrupt sources in the vector table are listed in order of rank, from highest to lowest priority. If two or more enabled and pending interrupts are detected at the same time, the one with the highest priority is serviced first. Upon return from the interrupt service routine, the next highest-level pending interrupt is serviced.
If the VIS instruction is executed, but no interrupts are en­abled and pending, the lowest-priority interrupt vector is used, and a jump is made to the corresponding address in the vector table. This is an unusual occurrence, and may be the result of an error. It can legitimately result from a change in the enable bits or pending flags prior to the execution of the VIS instruction, such as executing a single cycle instruc­tion which clears an enable flag at the same time that the pending flag is set. It can also result, however,from inadvert­ent execution of the VIS command outside of the context of an interrupt.
The default VIS interrupt vector can be useful for applica­tions in which time critical interrupts can occur during the servicing of another interrupt. Rather than restoring the pro­gram context (A, B, X, etc.) and executing the RETI instruc­tion, an interrupt service routine can be terminated by return­ing to the VIS instruction. In this case, interrupts will be serviced in turn until no further interrupts are pending and the default VIS routine is started. After testing the GIE bit to ensure that execution is not erroneous, the routine should restore the program context and execute the RETI to return to the interrupted program.
This technique can save up to fifty instruction cycles (t
c
), or more, (50µs at 10 MHz oscillator) of latency for pending in­terrupts with a penalty of fewer than ten instruction cycles if no further interrupts are pending.
To ensure reliable operation, the user should always use the VIS instruction to determine the source of an interrupt. Al­though it is possible to poll the pending bits to detect the source of an interrupt, this practice is not recommended. The use of polling allows the standard arbitration ranking to be al­tered, but the reliability of the interrupt system is compro­mised. The polling routine must individually test the enable and pending bits of each maskable interrupt. If a Software Trap interrupt should occur, it will be serviced last, even though it should have the highest priority. Under certain con­ditions, a Software Trap could be triggered but not serviced, resulting in an inadvertent “locking out” of all maskable inter­rupts by the Software Trap pending flag. Problems such as this can be avoided by using VIS instruction.
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Interrupts (Continued)
TABLE 4. Interupt Vector Table
Arbitration Vector (Note 32)
Ranking Source Description Address
Hi-Low Byte
(1) Highest Software INTR Instruction 0yFE–0yFF (2) Reserved 0yFC–0yFD (3) External Pin G0 Edge 0yFA–0yFB (4) Timer T0 Underflow 0yF8–0yF9 (5) Timer T1 T1A/Underflow 0yF6–0yF7 (6) Timer T1 T1B 0yF4–0yF5 (7) MICROWIRE/PLUS BUSY Low 0yF2–0yF3 (8) Reserved 0yF0–0yF1 (9) Reserved 0yEE–0yEF (10) Reserved 0yEC–0yED (11) Timer T2 T2A/Underflow 0yEA–0yEB (12) Timer T2 T2B 0yE8–0yE9 (13) Timer T3 T3A/Underflow 0yE6–0yE7 (14) Timer T3 T3B 0yE4–0yE5 (15) Port L/Wakeup Port L Edge 0yE2–0yE3 (16) Lowest Default VIS Instr. Execution 0yE0–0yE1
without Any Interrupts
Note 32: y is a variable which represents the VIS block. VIS and the vector table must be located in the same 256-byte block except if VIS is located at the last ad­dress of a block. In this case, the table must be in the next block.
VIS Execution
When the VIS instruction is executed it activates the arbitra­tion logic. The arbitration logic generates an even number between E0 and FE (E0, E2, E4, E6 etc...) depending on which active interrupt has the highest arbitration ranking at the time of the 1st cycle of VIS is executed. For example, if the software trap interrupt is active, FE is generated. If the external interrupt is active and the software trap interrupt is not, then FA is generated and so forth. If the only active inter­rupt is software trap, than E0 is generated. This number re­places the lower byte of the PC. The upper byte of the PC re­mains unchanged. The new PC is therefore pointing to the
vector of the active interrupt with the highest arbitration rank­ing. This vector is read from program memory and placed into the PC which is now pointed to the 1st instruction of the service routine of the active interrupt with the highest arbitra­tion ranking.
Figure 15
illustrates the different steps performed by the VIS
instruction.
Figure 16
shows a flowchart for the VIS instruc-
tion. The non-maskable interrupt pending flag is cleared by the
RPND (Reset Non-Maskable Pending Bit) instruction (under certain conditions) and upon RESET.
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Interrupts (Continued)
DS100076-29
FIGURE 15. VIS Operation
DS100076-30
FIGURE 16. VIS Flowchart
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Interrupts (Continued)
Programming Example: External Interrupt
PSW =00EF CNTRL =00EE RBIT 0,PORTGC RBIT 0,PORTGD ; G0 pin configured Hi-Z SBIT IEDG, CNTRL ; Ext interrupt polarity; falling edge SBIT EXEN, PSW ; Enable the external interrupt SBIT GIE, PSW ; Set the GIE bit
WAIT: JP WAIT ; Wait for external interrupt
. . . .=0FF ; The interrupt causes a VIS ; branch to address 0FF
; The VIS causes a branch to
;interrupt vector table . . . .=01FA ; Vector table (within 256 byte .ADDRW SERVICE ; of VIS inst.) containing the ext
; interrupt service routine . .
INT_EXIT:
RETI . .
SERVICE: RBIT EXPND, PSW ; Interrupt Service Routine
; Reset ext interrupt pend. bit . . . JP INT_EXIT ; Return, set the GIE bit
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Interrupts (Continued)
NON-MASKABLE INTERRUPT
Pending Flag
There is a pending flag bit associated with the non-maskable interrupt, called STPND. This pending flag is not memory­mapped and cannot be accessed directly by the software.
The pending flag is reset to zero when a device Reset oc­curs. When the non-maskable interrupt occurs, the associ­ated pending bit is set to 1. The interrupt service routine should contain an RPND instruction to reset the pending flag to zero. The RPND instruction always resets the STPND flag.
Software Trap
The Software Trap is a special kind of non-maskable inter­rupt which occurs when the INTR instruction (used to ac­knowledge interrupts) is fetched from program memory and placed in the instruction register. This can happen in a vari­ety of ways, usually because of an error condition. Some ex­amples of causes are listed below.
If the program counter incorrectly points to a memory loca­tion beyond the available program memory space, the non­existent or unused memory location returns zeroes which is interpreted as the INTR instruction.
If the stack is popped beyond the allowed limit (address 06F Hex), a 7FFF will be loaded into the PC, if this last location in program memory is unprogrammed or unavailable, a Soft­ware Trap will be triggered.
A Software Trap can be triggered by a temporary hardware condition such as a brownout or power supply glitch.
The Software Trap indicates an unusual or unknown error condition. Generally, returning to normal execution at the point where the Software Trap occurred cannot be done re­liably. Therefore, the Software Trap service routine should reinitialize the stack pointer and perform a recovery proce­dure that restarts the software at some known point, similar to a device Reset, but not necessarily performing all the same functions as a device Reset. The routine must also ex­ecute the RPND instruction to reset the STPND flag. Other­wise, all other interrupts will be locked out. To the extent pos­sible, the interrupt routine should record or indicate the context of the device so that the cause of the Software Trap can be determined.
If the user wishes to return to normal execution from the point at which the Software Trap was triggered, the user must first execute RPND, followed by RETSK rather than RETI or RET. This is because the return address stored on the stack is the address of the INTR instruction that triggered the interrupt. The program must skip that instruction in order to proceed with the next one. Otherwise, an infinite loop of Software Traps and returns will occur.
Programming a return to normal execution requires careful consideration. If the Software Trap routine is interrupted by another Software Trap, the RPND instruction in the service routine for the second Software Trap will reset the STPND
flag; upon return to the first Software Trap routine, the STPND flag will have the wrong state. This will allow maskable interrupts to be acknowledged during the servicing of the first SoftwareTrap. Toavoid problems such as this, the user program should contain the Software Trap routine to perform a recovery procedure rather than a return to normal execution.
Under normal conditions, the STPND flag is reset by a RPND instruction in the Software Trap service routine. If a programming error or hardware condition (brownout, power supply glitch, etc.) sets the STPND flag without providing a way for it to be cleared, all other interrupts will be locked out. To alleviate this condition, the user can use extra RPND in­structions in the main program and in the WATCHDOG ser­vice routine (if present). There is no harm in executing extra RPND instructions in these parts of the program.
PORT L INTERRUPTS
Port L provides the user with an additional eight fully select­able, edge sensitive interrupts which are all vectored into the same service subroutine.
The GIE (Global Interrupt Enable) bit enables the interrupt function.
A control flag, LPEN, functions as a global interrupt enable for Port L interrupts. Setting the LPEN flag will enable inter­rupts and vice versa. A separate global pending flag is not needed since the register WKPND is adequate.
INTERRUPT SUMMARY
The device uses the following types of interrupts, listed be­low in order of priority:
1. The Software Trap non-maskable interrupt, triggered by the INTR (00 opcode) instruction. The Software Trap is acknowledged immediately. This interrupt service rou­tine can be interrupted only by another Software Trap. The Software Trap should end with two RPND instruc­tions followed by a restart procedure.
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Page 29
WATCHDOG
The device contains a WATCHDOG and clock monitor. The WATCHDOG is designed to detect the user program getting stuck in infinite loops resulting in loss of program control or “runaway” programs. The Clock Monitor is used to detect the absence of a clock or a very slow clock below a specified rate on the CKI pin.
The WATCHDOG consists of two independent logic blocks: WD UPPER and WD LOWER. WD UPPER establishes the upper limit on the service window and WD LOWER defines the lower limit of the service window.
Servicing the WATCHDOG consists of writing a specific value to a WATCHDOG Service Register named WDSVR which is memory mapped in the RAM. This value is com­posed of three fields, consisting of a 2-bit Window Select, a 5-bit Key Data field, and the 1-bit Clock Monitor Select field.
Table 5
shows the WDSVR register.
TABLE 5. WATCHDOG Service Register (WDSVR)
Window Key Data Clock
Select Monitor
X X 01100 Y 7 6 54321 0
Table 6
shows the four possible combinations of lower and upper limits for the WATCHDOG service window. This flex­ibility in choosing the WATCHDOG service window prevents any undue burden on the user software.
Bits 5, 4, 3, 2 and 1 of the WDSVR register represent the 5-bit Key Data field. The key data is fixed at 01100. Bit 0 of the WDSVR Register is the Clock Monitor Select bit.
TABLE 6. WATCHDOG Service Window Select
WDSVR WDSVR Clock Service Window
Bit 7 Bit 6 Monitor (Lower-Upper Limits)
0 0 x 2048–8k t
C
Cycles
0 1 x 2048–16k t
C
Cycles
1 0 x 2048–32k t
C
Cycles
1 1 x 2048–64k t
C
Cycles x x 0 Clock Monitor Disabled x x 1 Clock Monitor Enabled
Clock Monitor
The Clock Monitor aboard the device can be selected or de­selected under program control. The Clock Monitor is guar­anteed not to reject the clock if the instruction cycle clock (1/ t
c
) is greater or equal to 10 kHz. This equates to a clock input
rate on CKI of greater or equal to 100 kHz.
WATCHDOG Operation
The WATCHDOG and Clock Monitor are disabled during re­set. The device comes out of reset with the WATCHDOG armed, the WATCHDOG Window Select bits (bits 6, 7 of the WDSVR Register) set, and the Clock Monitor bit (bit 0 of the WDSVR Register) enabled. Thus, a Clock Monitor error will
The WDSVR register can be written to only once after reset and the key data (bits 5 through 1 of the WDSVR Register) must match to be a valid write. This write to the WDSVR reg­ister involves two irrevocable choices: (i) the selection of the WATCHDOG service window (ii) enabling or disabling of the Clock Monitor. Hence, the first write to WDSVR Register in­volves selecting or deselecting the Clock Monitor, select the WATCHDOG service window and match the WATCHDOG key data. Subsequent writes to the WDSVR register will compare the value being written by the user to the WATCH­DOG service window value and the key data (bits 7 through
1) in the WDSVR Register.
Table 5
shows the sequence of
events that can occur. The user must service the WATCHDOG at least once before
the upper limit of the service window expires. The WATCH­DOG may not be serviced more than once in every lower limit of the service window. The user may service the WATCHDOG as many times as wished in the time period be­tween the lower and upper limits of the service window. The first write to the WDSVR Register is also counted as a WATCHDOG service.
The WATCHDOG has an output pin associated with it. This is the WDOUT pin, on pin 1 of the port G. WDOUT is active low.The WDOUT pin is in the high impedance state in the in­active state. Upon triggering the WATCHDOG, the logic will pull the WDOUT (G1) pin low for an additional 16 t
c
–32 t
c
cycles after the signal level on WDOUT pin goes below the lower Schmitt trigger threshold. After this delay, the device will stop forcing the WDOUT output low.
The WATCHDOG service window will restart when the WD­OUT pin goes high. It is recommended that the user tie the WDOUT pin back to V
CC
through a resistor in order to pull
WDOUT high. AWATCHDOG service while the WDOUT signal is active will
be ignored. The state of the WDOUT pin is not guaranteed on reset, but if it powers up low then the WATCHDOG will time out and WDOUT will enter high impedance state.
The Clock Monitor forces the G1 pin low upon detecting a clock frequency error. The Clock Monitor error will continue until the clock frequency has reached the minimum specified value, after which the G1 output will enter the high imped­ance TRI-STATE mode following 16 t
c
–32 tcclock cycles. The Clock Monitor generates a continual Clock Monitor error if the oscillator fails to start, or fails to reach the minimum specified frequency. The specification for the Clock Monitor is as follows:
1/t
c
>
10 kHz— No clock rejection.
1/t
c
<
10 Hz— Guaranteed clock rejection.
WATCHDOG AND CLOCK MONITOR SUMMARY
The following salient points regarding the WATCHDOG and CLOCK MONITOR should be noted:
•
Both the WATCHDOG and CLOCK MONITOR detector circuits are inhibited during RESET.
•
Following RESET, the WATCHDOG and CLOCK MONI­TOR are both enabled, with the WATCHDOG having the maximum service window selected.
•
The WATCHDOG service window and CLOCK MONI­TOR enable/disable option can only be changed once, during the initial WATCHDOG service following RESET.
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WATCHDOG Operation (Continued)
•
The initial WATCHDOG service must match the key data value in the WATCHDOG Service register WDSVR in or­der to avoid a WATCHDOG error.
•
Subsequent WATCHDOG services must match all three data fields in WDSVR in order to avoid WATCHDOG er­rors.
•
The correct key data value cannot be read from the WATCHDOG Service register WDSVR. Any attempt to read this key data value of 01100 from WDSVR will read as key data value of all 0’s.
•
The WATCHDOG detector circuit is inhibited during both the HALT and IDLE modes.
•
The CLOCK MONITOR detector circuit is active during both the HALT and IDLE modes. Consequently, the de­vice inadvertently entering the HALT mode will be de­tected as a CLOCK MONITOR error (provided that the CLOCK MONITOR enable option has been selected by the program).
•
With the single-pin R/C oscillator mask option selected and the CLKDLY bit reset, the WATCHDOG service win­dow will resume following HALT mode from where it left off before entering the HALT mode.
•
With the crystal oscillator mask option selected, or with the single-pin R/C oscillator mask option selected and the CLKDLYbit set, the WATCHDOG service window will be set to its selected value from WDSVR following HALT. Consequently, the WATCHDOG should not be serviced for at least 2048 instruction cycles following HALT, but must be serviced within the selected window to avoid a WATCHDOG error.
•
The IDLE timer T0 is not initialized with RESET.
•
The user can sync in to the IDLE counter cycle with an IDLE counter (T0) interrupt or by monitoring the T0PND flag. The T0PND flag is set whenever the thirteenth bit of the IDLE counter toggles (every 4096 instruction cycles). The user is responsible for resetting the T0PND flag.
•
A hardware WATCHDOG service occurs just as the de­vice exits the IDLE mode. Consequently, the WATCH­DOG should not be serviced for at least 2048 instruction cycles following IDLE, but must be serviced within the se­lected window to avoid a WATCHDOG error.
•
Following RESET, the initial WATCHDOG service (where the service window and the CLOCK MONITOR enable/ disable must be selected) may be programmed any­where within the maximum service window (65,536 in­struction cycles) initialized by RESET.Note that this initial WATCHDOG service may be programmed within the ini­tial 2048 instruction cycles without causing a WATCH­DOG error.
Detection of Illegal Conditions
The device can detect various illegal conditions resulting from coding errors, transient noise, power supply voltage drops, runaway programs, etc.
Reading of undefined ROM gets zeros. The opcode for soft­ware interrupt is zero. If the program fetches instructions from undefined ROM, this will force a software interrupt, thus signaling that an illegal condition has occurred.
Thus, the chip can detect the following illegal conditions:
1. Executing from undefined ROM
2. Over “POP”ing the stack by having more returns than calls.
When the software interrupt occurs, the user can re-initialize the stack pointer and do a recovery procedure before restart­ing (this recovery program is probably similar to that follow­ing reset, but might not contain the same program initializa­tion procedures).
MICROWIRE/PLUS
MICROWIRE/PLUS is a serial synchronous communications interface. The MICROWIRE/PLUS capability enables the de­vice to interface with any of National Semiconductor’s MI­CROWIRE peripherals (i.e. A/D converters, display drivers, E
2
PROMs etc.) and with other microcontrollers which sup­port the MICROWIRE interface. It consists of an 8-bit serial shift register (SIO) with serial data input (SI), serial data out­put (SO) and serial shift clock (SK).
Figure 17
shows a block
diagram of the MICROWIRE/PLUS logic.
The shift clock can be selected from either an internal source or an external source. Operating the MICROWIRE/PLUS ar­rangement with the internal clock source is called the Master mode of operation. Similarly, operating the MICROWIRE/ PLUS arrangement with an external shift clock is called the Slave mode of operation.
Table8
details the different
clock rates that may be selected.
DS100076-15
FIGURE 17. MICROWIRE/PLUS Block Diagram
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Page 31
MICROWIRE/PLUS (Continued)
TABLE 7. WATCHDOG Service Actions
Key Window Clock Action
Data Data Monitor
Match Match Match Valid Service: Restart Service Window
Don’t Care Mismatch Don’t Care Error: Generate WATCHDOG Output
Mismatch Don’t Care Don’t Care Error: Generate WATCHDOG Output
Don’t Care Don’t Care Mismatch Error: Generate WATCHDOG Output
TABLE 8. MICROWIRE/PLUS
Master Mode Clock Selection SL1 SL0 SK
0 0 2xt
c
0 1 4xt
c
1 x 8xt
c
Where tcis the instruction cycle clock
MICROWIRE/PLUS OPERATION
Setting the BUSY bit in the PSW register causes the MICROWIRE/PLUS to start shifting the data. It gets reset when eight data bits have been shifted. The user may reset the BUSY bit by software to allow less than 8 bits to shift. If enabled, an interrupt is generated when eight data bits have been shifted. The device may enter the MICROWIRE/PLUS mode either as a Master or as a Slave.
Figure 18
shows how two microcontroller devices and several peripherals may be interconnected using the MICROWIRE/PLUS arrangements.
Warning:
The SIO register should only be loaded when the SK clock is low. Loading the SIO register while the SK clock is high will result in undefined data in the SIO register. SK clock is nor­mally low when not shifting.
Setting the BUSY flag when the input SK clock is high in the MICROWIRE/PLUS slave mode may cause the current SK clock for the SIO shift register to be narrow. For safety, the BUSY flag should only be set when the input SK clock is low.
MICROWIRE/PLUS Master Mode Operation
In the MICROWIRE/PLUS Master mode of operation the shift clock (SK) is generated internally by the device. The MI­CROWIRE Master always initiates all data exchanges. The MSEL bit in the CNTRL register must be set to enable the SO and SK functions onto the G Port. The SO and SK pins must also be selected as outputs by setting appropriate bits in the Port G configuration register.
Table 9
summarizes the
bit settings required for Master mode of operation.
MICROWIRE/PLUS Slave Mode Operation
In the MICROWIRE/PLUS Slave mode of operation the SK clock is generated by an external source. Setting the MSEL bit in the CNTRL register enables the SO and SK functions
onto the G Port. The SK pin must be selected as an input and the SO pin is selected as an output pin by setting and re­setting the appropriate bits in the Port G configuration regis­ter.
Table 9
summarizes the settings required to enter the
Slave mode of operation. The user must set the BUSY flag immediately upon entering
the Slave mode. This will ensure that all data bits sent by the Master will be shifted properly. After eight clock pulses the BUSY flag will be cleared and the sequence may be re­peated.
Alternate SK Phase Operation
The device allows either the normal SK clock or an alternate phase SK clock to shift data in and out of the SIO register. In both the modes the SK is normally low. In the normal mode data is shifted in on the rising edge of the SK clock and the data is shifted out on the falling edge of the SK clock. The SIO register is shifted on each falling edge of the SK clock. In the alternate SK phase operation, data is shifted in on the falling edge of the SK clock and shifted out on the rising edge of the SK clock.
A control flag, SKSEL, allows either the normal SK clock or the alternate SK clock to be selected. Resetting SKSEL causes the MICROWIRE/PLUS logic to be clocked from the normal SK signal. Setting the SKSEL flag selects the alter­nate SK clock. The SKSEL is mapped into the G6 configura­tion bit. The SKSEL flag will power up in the reset condition, selecting the normal SK signal.
TABLE 9. MICROWIRE/PLUS Mode Settings
This table assumes that the control flag MSEL is set.
G4 (SO) G5 (SK) G4 G5 Operation
Config. Bit Config. Bit Fun. Fun.
1 1 SO Int. MICROWIRE/PLUS
SK Master
0 1 TRI- Int. MICROWIRE/PLUS
STATE SK Master
1 0 SO Ext. MICROWIRE/PLUS
SK Slave
0 0 TRI- Ext. MICROWIRE/PLUS
STATE SK Slave
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Page 32
MICROWIRE/PLUS (Continued)
DS100076-16
FIGURE 18. MICROWIRE/PLUS Application
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Page 33
Memory Map
All RAM, ports and registers (except A and PC) are mapped into data memory address space.
Address Contents
S/ADD REG
0000 to 006F On-Chip RAM bytes (112 bytes) 0070 to 007F Unused RAM Address Space (Reads
As All Ones)
xx80 to xxAF Unused RAM Address Space (Reads
Undefined Data) xxB0 Timer T3 Lower Byte xxB1 Timer T3 Upper Byte xxB2 Timer T3 Autoload Register T3RA
Lower Byte xxB3 Timer T3 Autoload Register T3RA
Upper Byte xxB4 Timer T3 Autoload Register T3RB
Lower Byte xxB5 Timer T3 Autoload Register T3RB
Upper Byte xxB6 Timer T3 Control Register xxB7 Comparator Select Register (CMPSL) xxB8 to xxBF Reserved xxC0 Timer T2 Lower Byte xxC1 Timer T2 Upper Byte xxC2 Timer T2 Autoload Register T2RA
Lower Byte xxC3 Timer T2 Autoload Register T2RA
Upper Byte xxC4 Timer T2 Autoload Register T2RB
Lower Byte xxC5 Timer T2 Autoload Register T2RB
Upper Byte xxC6 Timer T2 Control Register xxC7 WATCHDOG Service Register
(Reg:WDSVR) xxC8 MIWU Edge Select Register
(Reg:WKEDG) xxC9 MIWU Enable Register (Reg:WKEN) xxCA MIWU Pending Register (Reg:WKPND) xxCB Reserved xxCC Reserved xxCD to xxCF Reserved xxD0 Port L Data Register xxD1 Port L Configuration Register xxD2 Port L Input Pins (Read Only) xxD3 Reserved for Port L xxD4 Port G Data Register xxD5 Port G Configuration Register xxD6 Port G Input Pins (Read Only) xxD7 Port I Input Pins (Read Only) xxD8 Port C Data Register xxD9 Port C Configuration Register
Address Contents
S/ADD REG
xxDA Port C Input Pins (Read Only) xxDB Reserved for Port C xxDC Port D xxDD to xxDF Reserved xxE0 to xxE5 Reserved xxE6 Timer T1 Autoload Register T1RB
Lower Byte
xxE7 Timer T1 Autoload Register T1RB
Upper Byte xxE8 ICNTRL Register xxE9 MICROWIRE/PLUS Shift Register xxEA Timer T1 Lower Byte xxEB Timer T1 Upper Byte xxEC Timer T1 Autoload Register T1RA
Lower Byte xxED Timer T1 Autoload Register T1RA
Upper Byte xxEE CNTRL Control Register xxEF PSW Register xxF0 to FB On-Chip RAM, Mapped as Registers xxFC X Register xxFD SP Register xxFE B Register xxFF S Register 0100 to 017F On-Chip RAM, 128 Bytes
Reading memory locations 0070H–007FH (Segment 0) will return all ones. Reading unused memory locations 0080H–00AFH (Segment 0) will return undefined data. Reading memory locations from other unused Segments (i.e., Segment 2, Segment 3, … etc.) will return undefined data.
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Page 34
Addressing Modes
OPERAND ADDRESSING MODES Register Indirect
Register Indirect (with auto post increment or decrement of pointer)
This addressing mode is used with the LD and X instruc­tions. The operand is the data memory addressed by the B pointer or X pointer. This is a register indirect mode that au­tomatically post increments or decrements the B or X regis­ter after executing the instruction.
Direct
The instruction contains an 8-bit address field that directly points to the data memory for the operand.
Immediate
The instruction contains an 8-bit immediate field as the oper­and.
Short Immediate
This addressing mode is used with the Load B Immediate in­struction. The instruction contains a 4-bit immediate field as the operand.
Indirect
This addressing mode is used with the LAID instruction. The contents of the accumulator are used as a partial address (lower 8 bits of PC) for accessing a data operand from the program memory.
TRANSFER OF CONTROL ADDRESSING MODES
Relative
This mode is used for the JP instruction, with the instruction field being added to the program counter to get the new pro­gram location. JP has a range from −31 to +32 to allow a 1-byte relative jump (JP + 1 is implemented by a NOP in­struction). There are no “pages” when using JP, since all 15 bits of PC are used.
Absolute
This mode is used with the JMP and JSR instructions, with the instruction field of 12 bits replacing the lower 12 bits of the program counter (PC). This allows jumping to any loca­tion in the current 4k program memory segment.
Absolute Long
This mode is used with the JMPL and JSRL instructions, with the instruction field of 15 bits replacing the entire 15 bits of the program counter (PC). This allows jumping to any loca­tion up to 32k in the program memory space.
Indirect
This mode is used with the JID instruction. The contents of the accumulator are used as a partial address (lower 8 bits of PC) for accessing a location in the program memory. The contents of this program memory location serve as a partial address (lower 8 bits of PC) for the jump to the next instruc­tion.
Note: The VIS is a special case of the Indirect Transfer of Control addressing
mode, where the double byte vector associated with the interrupt is transferred from adjacent addresses in the program memory into the program counter (PC) in order to jump to the associated interrupt ser­vice routine.
Instruction Set
Register and Symbol Definition
Registers
A 8-Bit Accumulator Register B 8-Bit Address Register X 8-Bit Address Register S 8-Bit Segment Register SP 8-Bit Stack Pointer Register PC 15-Bit Program Counter Register PU Upper 7 Bits of PC PL Lower 8 Bits of PC C 1 Bit of PSW Register for Carry HC 1 Bit of PSW Register for Half Carry GIE 1 Bit of PSW Register for Global Interrupt
Enable VU Interrupt Vector Upper Byte VL Interrupt Vector Lower Byte
Symbols
[B] Memory Indirectly Addressed by B Register [X] Memory Indirectly Addressed by X Register MD Direct Addressed Memory Mem Direct Addressed Memory or [B] Meml Direct Addressed Memory or [B] or
Immediate Data Imm 8-Bit Immediate Data Reg Register Memory: Addresses F0 to FF
(Includes B, X and SP) Bit Bit Number (0 to 7)
←
Loaded with
↔
Exchanged with
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Page 35
Instruction Set (Continued)
INSTRUCTION SET
ADD A,Meml ADD A←A + Meml ADC A,Meml ADD with Carry A←A+Meml+C,C←Carry
HC←Half Carry
SUBC A,Meml Subtract with Carry A←A−MemI+C,C←Carry
HC←Half Carry AND A,Meml Logical AND A←A and Meml ANDSZ A,Imm Logical AND Immed., Skip if Zero Skip next if (A and Imm)=0 OR A,Meml Logical OR A←A or Meml XOR A,Meml Logical EXclusive OR A←A xor Meml IFEQ MD,Imm IF EQual Compare MD and Imm, Do next if MD=Imm IFEQ A,Meml IF EQual Compare A and Meml, Do next if A=Meml IFNE A,Meml IF Not Equal Compare A and Meml, Do next if A
≠
Meml
IFGT A,Meml IF Greater Than Compare A and Meml, Do next if A
>
Meml
IFBNE
#
If B Not Equal Do next if lower 4 bits of B≠Imm DRSZ Reg Decrement Reg., Skip if Zero Reg←Reg − 1, Skip if Reg=0 SBIT
#
,Mem Set BIT 1 to bit, Mem (bit=0 to 7 immediate)
RBIT
#
,Mem Reset BIT 0 to bit, Mem
IFBIT
#
,Mem IF BIT If bit in A or Mem is true do next instruction RPND Reset PeNDing Flag Reset Software Interrupt Pending Flag X A,Mem EXchange A with Memory A
↔
Mem
X A,[X] EXchange A with Memory [X] A
↔
[X] LD A,Meml LoaD A with Memory A←Meml LD A,[X] LoaD A with Memory [X] A←[X] LD B,Imm LoaD B with Immed. B←Imm LD Mem,Imm LoaD Memory Immed Mem←Imm LD Reg,Imm LoaD Register Memory Immed. Reg←Imm XA,[B
±
] EXchange A with Memory [B] A↔[B], (B←B±1)
XA,[X
±
] EXchange A with Memory [X] A↔[X], (X←X±1)
LD A, [B
±
] LoaD A with Memory [B] A←[B], (B←B±1)
LD A, [X
±
] LoaD A with Memory [X] A←[X], (X←X±1)
LD [B
±
],Imm LoaD Memory [B] Immed. [B]←Imm, (B←B±1) CLR A CLeaR A A←0 INC A INCrement A A←A+1 DEC A DECrement A A←A−1 LAID Load A InDirect from ROM A←ROM (PU,A) DCOR A Decimal CORrect A A←BCD correction of A (follows ADC, SUBC) RRC A Rotate A Right thru C C→A7→…→A0→C RLC A Rotate A Left thru C C←A7←…←A0←C SWAP A SWAP nibbles of A A7…A4
↔
A3…A0 SC Set C C←1, HC←1 RC Reset C C←0, HC←0 IFC IF C IF C is true, do next instruction IFNC IF Not C If C is not true, do next instruction POP A POP the stack into A SP←SP+1,A←[SP] PUSH A PUSH A onto the stack [SP]←A, SP←SP−1 VIS Vector to Interrupt Service Routine PU←[VU], PL←[VL] JMPL Addr. Jump absolute Long PC←ii (ii=15 bits, 0 to 32k) JMP Addr. Jump absolute PC9…0←i(i=12 bits) JP Disp. Jump relative short PC←PC+r(ris−31to+32, except 1)
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Page 36
Instruction Set (Continued)
INSTRUCTION SET (Continued)
JSRL Addr. Jump SubRoutine Long [SP]←PL, [SP−1]←PU,SP−2, PC←ii JSR Addr Jump SubRoutine [SP]←PL, [SP−1]←PU,SP−2, PC9…0←i JID Jump InDirect PL←ROM (PU,A) RET RETurn from subroutine SP + 2, PL←[SP], PU←[SP−1] RETSK RETurn and SKip SP + 2, PL←[SP],PU←[SP−1] RETI RETurn from Interrupt SP + 2, PL←[SP],PU←[SP−1],GIE←1 INTR Generate an Interrupt [SP]←PL, [SP−1]←PU, SP−2, PC←0FF NOP No OPeration PC←PC+1
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Page 37
Instruction Execution Time
Most instructions are single byte (with immediate addressing mode instructions taking two bytes).
Most single byte instructions take one cycle time to execute. See the BYTES and CYCLES per INSTRUCTION table for
details.
Bytes and Cycles per Instruction
The following table shows the number of bytes and cycles for each instruction in the format of byte/cycle.
Arithmetic and Logic Instructions
[B] Direct Immed.
ADD 1/1 3/4 2/2 ADC 1/1 3/4 2/2 SUBC 1/1 3/4 2/2 AND 1/1 3/4 2/2 OR 1/1 3/4 2/2 XOR 1/1 3/4 2/2 IFEQ 1/1 3/4 2/2 IFNE 1/1 3/4 2/2 IFGT 1/1 3/4 2/2 IFBNE 1/1 DRSZ 1/3 SBIT 1/1 3/4 RBIT 1/1 3/4 IFBIT 1/1 3/4
RPND 1/1
Instructions Using A & C
CLRA 1/1 INCA 1/1 DECA 1/1 LAID 1/3 DCOR 1/1 RRCA 1/1 RLCA 1/1 SWAPA 1/1 SC 1/1 RC 1/1 IFC 1/1 IFNC 1/1 PUSHA 1/3 POPA 1/3 ANDSZ 2/2
Transfer of Control Instructions
JMPL 3/4 JMP 2/3 JP 1/3 JSRL 3/5 JSR 2/5 JID 1/3 VIS 1/5 RET 1/5 RETSK 1/5 RETI 1/5 INTR 1/7 NOP 1/1
Memory Transfer Instructions
Register Direct Immed. Register Indirect
Indirect Auto Incr. & Decr.
[B] [X] [B+, B−] [X+, X−]
X A, (Note *NO TARGET FOR FNXref NS7829*)
1/1 1/3 2/3 1/2 1/3
LD A, (Note *NO TARGET FOR FNXref NS7829*)
1/1 1/3 2/3 2/2 1/2 1/3
LD B, Imm 1/1 (IF B
<
16)
LD B, Imm 2/2 (IF B
>
15) LD Mem, Imm 2/2 3/3 2/2 LD Reg, Imm 2/3 IFEQ MD, Imm 3/3
Note 33:
=
>
Memory location addressed by B or X or directly.
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Page 38
Opcode Table
Upper Nibble
F E D C BA9 876 5 4 3 2 10
Lower Nibble
JP−15 JP−31 LD 0F0, #i DRSZ
0F0
RRCA RC ADC
A,#i
ADC
A,[B]
IFBIT
0,[B]
ANDSZ
A, #i
LD
B,#0F
IFBNE 0 JSR
x000–x0FF
JMP
x000–x0FF
JP+17 INTR 0
JP−14 JP−30 LD 0F1, #i DRSZ
0F1
* SC SUBC
A, #i
SUBC
A,[B]
IFBIT
1,[B]
*LD
B,#0E
IFBNE 1 JSR
x100–x1FF
JMP
x100–x1FF
JP+18 JP+2 1
JP−13 JP−29 LD 0F2, #i DRSZ
0F2
X
A,[X+]
X
A,[B+]
IFEQ
A,#i
IFEQ
A,[B]
IFBIT
2,[B]
*LD
B,#0D
IFBNE 2 JSR
x200–x2FF
JMP
x200–x2FF
JP+19 JP+3 2
JP−12 JP−28 LD 0F3, #i DRSZ
0F3
X
A,[X−]
X
A,[B−]
IFGT
A,#i
IFGT
A,[B]
IFBIT
3,[B]
*LD
B,#0C
IFBNE 3 JSR
x300–x3FF
JMP
x300–x3FF
JP+20 JP+4 3
JP−11 JP−27 LD 0F4, #i DRSZ
0F4
VIS LAID ADD
A,#i
ADD
A,[B]
IFBIT
4,[B]
CLRA LD
B,#0B
IFBNE 4 JSR
x400–x4FF
JMP
x400–x4FF
JP+21 JP+5 4
JP−10 JP−26 LD 0F5, #i DRSZ
0F5
RPND JID AND
A,#i
AND
A,[B]
IFBIT
5,[B]
SWAPA LD
B,#0A
IFBNE 5 JSR
x500–x5FF
JMP
x500–x5FF
JP+22 JP+6 5
JP−9 JP−25 LD 0F6, #i DRSZ
0F6
X A,[X] X
A,[B]
XOR
A,#i
XOR
A,[B]
IFBIT
6,[B]
DCORA LD
B,#09
IFBNE 6 JSR
x600–x6FF
JMP
x600–x6FF
JP+23 JP+7 6
JP−8 JP−24 LD 0F7, #i DRSZ
0F7
* * OR A,#i OR
A,[B]
IFBIT
7,[B]
PUSHA LD
B,#08
IFBNE 7 JSR
x700–x7FF
JMP
x700–x7FF
JP+24 JP+8 7
JP−7 JP−23 LD 0F8, #i DRSZ
0F8
NOP RLCA LD A,#i IFC SBIT
0,[B]
RBIT
0,[B]
LD
B,#07
IFBNE 8 JSR
x800–x8FF
JMP
x800–x8FF
JP+25 JP+9 8
JP−6 JP−22 LD 0F9, #i DRSZ
0F9
IFNE
A,[B]
IFEQ
Md,#i
IFNE
A,#i
IFNC SBIT
1,[B]
RBIT
1,[B]
LD
B,#06
IFBNE 9 JSR
x900–x9FF
JMP
x900–x9FF
JP+26 JP+10 9
JP−5 JP−21 LD 0FA, #i DRSZ
0FA
LD
A,[X+]
LD
A,[B+]
LD
[B+],#i
INCA SBIT
2,[B]
RBIT
2,[B]
LD
B,#05
IFBNE 0A JSR
xA00–xAFF
JMP
xA00–xAFF
JP+27 JP+11 A
JP−4 JP−20 LD 0FB, #i DRSZ
0FB
LD
A,[X−]
LD
A,[B−]
LD
[B−],#i
DECA SBIT
3,[B]
RBIT
3,[B]
LD
B,#04
IFBNE 0B JSR
xB00–xBFF
JMP
xB00–xBFF
JP+28 JP+12 B
JP−3 JP−19 LD 0FC, #i DRSZ
0FC
LD
Md,#i
JMPL X A,Md POPA SBIT
4,[B]
RBIT
4,[B]
LD
B,#03
IFBNE 0C JSR
xC00–xCFF
JMP
xC00–xCFF
JP+29 JP+13 C
JP−2 JP−18 LD 0FD, #i DRSZ
0FD
DIR JSRL LD
A,Md
RETSK SBIT
5,[B]
RBIT
5,[B]
LD
B,#02
IFBNE 0D JSR
xD00–xDFF
JMP
xD00–xDFF
JP+30 JP+14 D
JP−1 JP−17 LD 0FE, #i DRSZ
0FE
LD
A,[X]
LD
A,[B]
LD
[B],#i
RET SBIT
6,[B]
RBIT
6,[B]
LD
B,#01
IFBNE 0E JSR
xE00–xEFF
JMP
xE00–xEFF
JP+31 JP+15 E
JP−0 JP−16 LD 0FF, #i DRSZ
0FF
* * LD B,#i RETI SBIT
7,[B]
RBIT
7,[B]
LD
B,#00
IFBNE 0F JSR
xF00–xFFF
JMP
xF00–xFFF
JP+32 JP+16 F
Where,
i is the immediate data
Md is a directly addressed memory location
* is an unused opcode
The opcode 60 Hex is also the opcode for IFBIT #i,A
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Page 39
Mask Options
The mask programmable options are shown below. The op­tions are programmed at the same time as the ROM pattern submission.
OPTION 1: CLOCK CONFIGURATION
= 1 Crystal Oscillator (CKI/10)
G7 (CKO) is clock generator output to crystal/resonator CKI is the clock input
= 2 Single-pin RC controlled
oscillator (CKI/10) G7 is available as a HALT restart and/or general purpose input
OPTION 2: HALT
= 1 Enable HALT mode = 2 Disable HALT mode
OPTION 3: BONDING
= 1 44-Pin PLCC
Development Tools Support
OVERVIEW
National is engaged with an international community of inde­pendent 3rd party vendors who provide hardware and soft­ware development tool support. Through National’s interac­tion and guidance, these tools cooperate to form a choice of solutions that fits each developer’s needs.
This section provides a summary of the tool and develop­ment kits currently available. Up-to-date information, selec­tion guides, free tools, demos, updates, and purchase infor­mation can be obtained at our web site at: www.national.com/cop8.
SUMMARY OF TOOLS COP8 Evaluation Tools
•
COP8–NSEVAL: Free Software Evaluation package for Windows. A fully integrated evaluation environment for COP8, including versions of WCOP8 IDE (Integrated De­velopment Environment), COP8-NSASM, COP8-MLSIM, COP8C, DriveWay
™
COP8, Manuals, and other COP8
information.
•
COP8–MLSIM: Free Instruction Level Simulator tool for Windows. For testing and debugging software instruc­tions only (No I/O or interrupt support).
•
COP8–EPU: Very Low cost COP8 Evaluation & Pro­gramming Unit. Windows based evaluation and hardware-simulation tool, with COP8 device programmer and erasable samples. Includes COP8-NSDEV, Drive­way COP8 Demo, MetaLink Debugger, I/O cables and power supply.
•
COP8–EVAL-ICUxx: Very Low cost evaluation and de­sign test board for COP8ACC and COP8SGx Families, from ICU. Real-time environment with add-on A/D, D/A, and EEPROM. Includes software routines and reference designs.
•
Manuals,Applications Notes, Literature: Available free from our web site at: www.national.com/cop8.
COP8 Integrated Software/Hardware Design Develop­ment Kits
•
COP8-EPU: Very Low cost Evaluation & Programming Unit. Windows based development and hardware­simulation tool for COPSx/xG families, with COP8 device programmer and samples. Includes COP8-NSDEV, Driveway COP8 Demo, MetaLink Debugger, cables and power supply.
•
COP8-DM: Moderate cost Debug Module from MetaLink. A Windows based, real-time in-circuit emulation tool with COP8 device programmer. Includes COP8-NSDEV, DriveWay COP8 Demo, MetaLink Debugger, power sup­ply, emulation cables and adapters.
COP8 Development Languages and Environments
•
COP8-NSASM: Free COP8 Assembler v5 for Win32. Macro assembler, linker, and librarian for COP8 software development. Supports all COP8 devices. (DOS/Win16 v4.10.2 available with limited support). (Compatible with WCOP8 IDE, COP8C, and DriveWay COP8).
•
COP8-NSDEV: Very low cost Software Development Package for Windows. An integrated development envi­ronment for COP8, including WCOP8 IDE, COP8­NSASM, COP8-MLSIM.
•
COP8C: Moderately priced C Cross-Compiler and Code Development System from Byte Craft (no code limit). In­cludes BCLIDE (Byte Craft Limited Integrated Develop­ment Environment) for Win32, editor, optimizing C Cross­Compiler, macro cross assembler, BC-Linker, and MetaLink tools support. (DOS/SUN versions available; Compiler is installable under WCOP8 IDE; Compatible with DriveWay COP8).
•
EWCOP8-KS: Very Low cost ANSI C-Compiler and Em­bedded Workbench from IAR (Kickstart version: COP8Sx/Fx only with 2k code limit; No FP). A fully inte­grated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, Liberian, C-Spy simulator/debugger, PLUS MetaLink EPU/DM emulator support.
•
EWCOP8-AS: Moderately priced COP8 Assembler and Embedded Workbench from IAR (no code limit). A fully in­tegrated Win32 IDE, macro assembler, editor, linker, li­brarian, and C-Spy high-level simulator/debugger with I/O and interrupts support. (Upgradeable with optional C-Compiler and/or MetaLink Debugger/Emulator sup­port).
•
EWCOP8-BL: Moderately priced ANSI C-Compiler and Embedded Workbench from IAR (Baseline version: All COP8 devices; 4k code limit; no FP). A fully integrated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker,librarian, and C-Spy high-level simulator/debugger. (Upgradeable; CWCOP8-M MetaLink tools interface sup­port optional).
•
EWCOP8: Full featured ANSI C-Compiler and Embed­ded Workbench for Windows from IAR (no code limit). A fully integrated Win32 IDE, ANSI C-Compiler, macro as­sembler, editor, linker, librarian, and C-Spy high-level simulator/debugger. (CWCOP8-M MetaLink tools inter­face support optional).
•
EWCOP8-M: Full featured ANSI C-Compiler and Embed­ded Workbench for Windows from IAR (no code limit). A fully integrated Win32 IDE, ANSI C-Compiler, macro as­sembler, editor, linker, librarian, C-Spy high-level simulator/debugger, PLUS MetaLink debugger/hardware interface (CWCOP8-M).
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Page 40
Development Tools Support
(Continued)
COP8 Productivity Enhancement Tools
•
WCOP8 IDE: Very Low cost IDE (Integrated Develop­ment Environment) from KKD. Supports COP8C, COP8­NSASM, COP8-MLSIM, DriveWay COP8, and MetaLink debugger under a common Windows Project Manage­ment environment. Code development, debug, and emu­lation tools can be launched from the project window framework.
•
DriveWay-COP8: Low cost COP8 Peripherals Code Generation tool from Aisys Corporation. Automatically generates tested and documented C or Assembly source code modules containing I/O drivers and interrupt han­dlers for each on-chip peripheral. Application specific code can be inserted for customization using the inte­grated editor. (Compatible with COP8-NSASM, COP8C, and WCOP8 IDE.)
•
COP8-UTILS: Free set of COP8 assembly code ex­amples, device drivers, and utilities to speed up code de­velopment.
•
COP8-MLSIM: Free Instruction Level Simulator tool for Windows. For testing and debugging software instruc­tions only (No I/O or interrupt support).
COP8 Real-Time Emulation Tools
•
COP8-DM: MetaLink Debug Module. A moderately priced real-time in-circuit emulation tool, with COP8 de­vice programmer. Includes COP8-NSDEV, DriveWay COP8 Demo, MetaLink Debugger, power supply, emula­tion cables and adapters.
•
IM-COP8: MetaLink iceMASTER®. A full featured, real- time in-circuit emulator for COP8 devices. Includes Met­aLink Windows Debugger, and power supply. Package­specific probes and surface mount adaptors are ordered separately.
COP8 Device Programmer Support
•
MetaLink’s EPU and Debug Module include development device programming capability for COP8 devices.
•
Third-party programmers and automatic handling equip­ment cover needs from engineering prototype and pilot production, to full production environments.
•
Factory programming available for high-volume require­ments.
TOOLS ORDERING NUMBERS FOR THE COP888GD FAMILY DEVICES
Vendor Tools Order Number Cost Notes
National COP8-NSEVAL COP8-NSEVAL Free Web site download
COP8-NSASM COP8-NSASM Free Included in EPU and DM. Web site download COP8-MLSIM COP8-MLSIM Free Included in EPU and DM. Web site download COP8-NSDEV COP8-NSDEV VL Included in EPU and DM. Order CD from website COP8-EPU Not available for this device COP8-DM Contact MetaLink Development
Devices
COP87L84GD/RD VL 16k or 32k OTP devices.
IM-COP8 Contact MetaLink
MetaLink COP8-EPU Not available for this device
COP8-DM DM4-COP8-888GD (10
MHz), plus PS-10, plus DM-COP8/xxx (ie. 28D)
M Included p/s (PS-10), target cable of choice (DIP or
PLCC; i.e. DM-COP8/40D), 16/20/28/40 DIP/SO and 44 PLCC programming sockets. Add target adapter (if needed)
DM Target Adapters
MHW-CONV39 L DM target converters for 28SO
IM-COP8 IM-COP8-AD-464 (-220)
(10 MHz maximum)
H Base unit 10 MHz; -220 = 220V; add probe card
(required) and target adapter (if needed); included software and manuals
IM Probe Card PC-888GD40DW-AD-10 M 10 MHz 40 DIP probe card; 2.5V to 6.0V
PC-888GD44PW-AD-10 M 10 MHz 44 PLCC probe card; 2.5V to 6.0V
ICU COP8-EVAL Not available for this device
KKD WCOP8-IDE WCOP8-IDE VL Included in EPU and DM
IAR EWCOP8-xx See summary above L - H Included all software and manuals
Byte
Craft
COP8C COP8C M Included all software and manuals
Aisys DriveWay COP8 DriveWay COP8 L Included all software and manuals
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Page 41
Development Tools Support (Continued)
OTP Programmers Contact vendors L - H For approved programmer listings and vendor
information, go to our OTP support page at: www.national.com/cop8
Cost: Free; VL =
<
$100; L = $100 - $300; M = $300 - $1k; H = $1k - $3k; VH = $3k - $5k
WHERE TO GET TOOLS
Tools are ordered directly from the following vendors. Please go to the vendor’s web site for current listings of distributors.
Vendor Home Office Electronic Sites Other Main Offices
Aisys U.S.A.: Santa Clara, CA www.aisysinc.com Distributors
1-408-327-8820 info
@
aisysinc.com
fax: 1-408-327-8830
Byte Craft U.S.A. www.bytecraft.com Distributors
1-519-888-6911 info
@
bytecraft.com
fax: 1-519-746-6751
IAR Sweden: Uppsala www.iar.se U.S.A.: San Francisco
+46 18 16 78 00 info
@
iar.se 1-415-765-5500
fax: +46 18 16 78 38 info
@
iar.com fax: 1-415-765-5503
info
@
iarsys.co.uk U.K.: London
info
@
iar.de +44 171 924 33 34
fax: +44 171 924 53 41 Germany: Munich +49 89 470 6022 fax: +49 89 470 956
ICU Sweden: Polygonvaegen www.icu.se Switzeland: Hoehe
+46 8 630 11 20 support
@
icu.se +41 34 497 28 20
fax: +46 8 630 11 70 support
@
icu.ch fax: +41 34 497 28 21 KKD Denmark: www.kkd.dk MetaLink U.S.A.: Chandler, AZ www.metaice.com Germany: Kirchseeon
1-800-638-2423 sales
@
metaice.com 80-91-5696-0
fax: 1-602-926-1198 support
@
metaice.com fax: 80-91-2386
bbs: 1-602-962-0013 islanger
@
metalink.de
www.metalink.de Distributors Worldwide
National U.S.A.: Santa Clara, CA www.national.com/cop8 Europe: +49 (0) 180 530 8585
1-800-272-9959 support
@
nsc.com fax: +49 (0) 180 530 8586
fax: 1-800-737-7018 europe.support
@
nsc.com Distributors Worldwide
The following companies have approved COP8 program­mers in a variety of configurations. Contact your local office or distributor. You can link to their web sites and get the lat­est listing of approved programmers from National’s COP8 OTP Support page at: www.national.com/cop8.
Advantech; Advin; BP Microsystems; Data I/O; Hi-Lo Sys­tems; ICE Technology; Lloyd Research; Logical Devices; MQP; Needhams; Phyton; SMS; Stag Programmers; Sys­tem General; Tribal Microsystems; Xeltek.
Customer Support
www.national.com41
Page 42
Physical Dimensions inches (millimeters) unless otherwise noted
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
National Semiconductor Corporation
Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: [email protected]
National Semiconductor Europe
Fax: +49 (0) 1 80-530 85 86
Email: [email protected] Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Français Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80
National Semiconductor Asia Pacific Customer Response Group
Tel: 65-2544466 Fax: 65-2504466 Email: [email protected]
National Semiconductor Japan Ltd.
Tel: 81-3-5639-7560 Fax: 81-3-5639-7507
www.national.com
Plastic Leaded Chip Carrier (V)
Order Number COP888GD-XXX/V or COP988GD-XXX/V
NS Package Number V44A
COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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