Philips p8xc557e8 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

P8xC557E8

8-bit microcontroller

Product speciﬁcation File under Integrated Circuits, IC20

1999 Mar 12

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

CONTENTS

1 FEATURES 2 GENERAL DESCRIPTION

2.1 Electromagnetic Compatibility (EMC)

2.2 Recommendation on ALE 3 ORDERING INFORMATION 4 BLOCK DIAGRAM 5 FUNCTIONAL DIAGRAM 6 PINNING INFORMATION

6.1 Pinning diagram

6.2 Pin description 7 FUNCTIONAL DESCRIPTION 8 MEMORY ORGANIZATION

8.1 Program Memory

8.2 Internal Data Memory

8.3 Addressing 9 I/O FACILITIES 10 PULSE WIDTH MODULATED OUTPUTS

(PWM)

10.1 Prescaler Frequency Control Register (PWMP)

10.2 Pulse Width Register 0 (PWM0)

10.3 Pulse Width Register 1 (PWM1) 11 ANALOG-TO-DIGITAL CONVERTER (ADC)

11.1 ADC features

11.2 ADC functional description

11.3 ADC timing

11.4 ADC configuration and operation

11.5 ADC during Idle and Power-down mode

11.6 ADC resolution and characteristics

11.7 ADC after reset

11.8 ADC Special Function Registers 12 TIMERS/COUNTERS

12.1 Timer 0 and Timer 1

12.2 Timer T2

12.3 Watchdog Timer T3 13 SERIAL I/O PORTS

13.1 Serial I/O Port: SIO0 (UART)

13.2 Serial I/O Port: SIO1 (I2C-bus interface) 14 INTERRUPT SYSTEM

14.1 Interrupt Enable Registers

14.2 Interrupt Handling

14.3 Interrupt Priority Structure

14.4 Interrupt vectors

14.5 Interrupt Enable and Priority Registers

15 POWER REDUCTION MODES

15.1 Idle mode

15.2 Power-down mode

15.3 Wake-up from Power-down mode

15.4 Status of external pins

15.5 Power Control Register (PCON) 16 OSCILLATOR CIRCUITS

16.1 XTAL1; XTAL2 oscillator: standard 80C51

16.2 XTAL3; XTAL4 oscillator: 32 kHz PLL oscillator (with Seconds timer)

17 RESET CIRCUITRY

17.1 Power-on Reset

18 INSTRUCTION SET

18.1 Addressing modes

18.2 80C51 family instruction set

18.3 Instruction set description

19 LIMITING VALUES 20 DC CHARACTERISTICS 21 AC CHARACTERISTICS 22 EPROM CHARACTERISTICS

22.1 Programming and verification

22.2 Security

23 SPECIAL FUNCTION REGISTERS

OVERVIEW

24 PACKAGE OUTLINES 25 SOLDERING

25.1 Introduction

25.2 Reflow soldering

25.3 Wave soldering

25.4 Repairing soldered joints

26 DEFINITIONS 27 LIFE SUPPORT APPLICATIONS 28 PURCHASE OF PHILIPS I2C COMPONENTS

1999 Mar 12 2

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

1 FEATURES

• 80C51 Central Processing Unit (CPU)

• 64 kbytes ROM (only P83C557E8)

• 64 kbytes EPROM (only P87C557E8)

• ROM/EPROM Code protection

• 2048 bytes RAM, expandable externally to 64 kbytes

• Two standard 16-bit timers/counters

• An additional 16-bit timer/counter coupled to four

capture registers and three compare registers

• A 10-bit Analog-to-Digital Converter (ADC) with eight multiplexed analog inputs and programmable autoscan

• Two 8-bit resolution, Pulse Width Modulation outputs

• Five 8-bit I/O ports plus one 8-bit input port shared with

analog inputs

• I2C-bus serial I/O port with byte oriented master and slave functions

• Full-duplex UART compatible with the standard 80C51

• On-chip Watchdog Timer

• 15 interrupt sources with 2 priority levels (2 to 6 external

sources possible)

• Phase-Locked Loop (PLL) oscillator with 32 kHz reference and software-selectable system clock frequency

• Seconds timer

• Software enable/disable of ALE output pulse

• Electromagnetic compatibility improvements

• Wake-up from Power-down by external or seconds

interrupt

• Frequency range for 80C51-family standard oscillator:

3.5 to 16 MHz

• Extended temperature range: −40 to +85 C

• Supply voltage: 4.5 to 5.5 V.

2 GENERAL DESCRIPTION

The 8-bit microcontrollers P80C557E8, P83C557E8 and P87C557E8 - hereafter referred to as P8xC557E8 - are manufactured in an advanced CMOS process and are derivatives of the 80C51 microcontroller family.

The P8xC557E8 contains a volatile 2048 bytes read/write Data Memory, five 8-bit I/O ports, one 8-bit input port, two 16-bit timer/event counters (identical to the timers of the 80C51), an additional 16-bit timer coupled to capture and compare latches, a 15-source, two-priority-level, nested interrupt structure, an 8-input ADC, a dual Digital-to-Analog Convertor (DAC), Pulse Width Modulated interface, two serial interfaces (UART and I2C-bus), a Watchdog Timer, an on-chip oscillator and timing circuits.

The P8xC557E8 is available in 3 versions:

• P80C557E8: ROMless version

• P83C557E8: containing a non-volatile 64 kbytes mask

programmable ROM

• P87C557E8: containing 64 kbytes programmable EPROM/OTP.

The P8xC557E8 is a control-oriented CPU with on-chip Program and Data Memory; it cannot be extended with external Program Memory. It can access up to 64 kbytes of external Data Memory. For systems requiring extra capability, the P8xC557E8 can be expanded using standard TTL compatible memories and peripherals.

In addition, the P8xC557E8 has two software selectable reduced power modes: Idle mode and Power-down mode. The Idle mode freezes the CPU while allowing the RAM, timers, serial ports, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, causing all other chip functions to be inoperative.The Power-down mode can be terminated by an external reset, by the seconds interrupt and by any one of the two external interrupts; see Section 15.3.

The device also functions as an arithmetic processor having facilities for both binary and BCD arithmetic as well as bit-handling capabilities. The instruction set of the P8xC557E8 is the same as the 80C51 and consists of over 100 instructions: 49 one-byte, 45 two-byte, and 17 three-byte. With a 16 MHz system clock, 58% of the instructions are executed in 0.75 µs and 40% in 1.5 µs. Multiply and divide instructions require 3 µs.

1999 Mar 12 3

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

2.1 Electromagnetic Compatibility (EMC)

Primary attention is paid to the reduction of electromagnetic emission of the microcontroller P8xC557E8. The following features reduce the electromagnetic emission and additionally improve the electromagnetic susceptibility:

• Four digital part supply voltage pins (V four digital ground pins (V pairs of V

DDn

and V

at two adjacent pins, at each side

SSn

SS1

to V

SS4

DD1

to V

DD4

) and

) are placed as

of the package.

• Separated VDD pins for the internal logic and the port buffers.

• Internal decoupling capacitance improves the EMC radiation behaviour and the EMC immunity.

• External capacitors should be connected across associated V

DDn

and V

pins (i.e. V

SSn

DD1

and V

SS1

). Lead length should be as short as possible. Ceramic chip capacitors are recommended (100 nF).

3 ORDERING INFORMATION

PACKAGE

TYPE NUMBER

NAME DESCRIPTION VERSION

P80C557E8EFB

P87C557E8EFB

(1)

(3)

(2)

QFP80

plastic quad ﬂat package; 80 leads (lead length 1.95 mm); body 14 × 20 × 2.8 mm

2.2 Recommendation on ALE

For applications that require no external memory or temporarily no external memory: the ALE output signal (pulses at a frequency of1⁄6× f

) can be disabled under

OSC

software control (bit RFI; SFR: PCON.5); if disabled, no ALE pulse will occur. ALE pin will be pulled down internally, switching an external address latch to a quiet state. The MOVX instruction will still toggle ALE (external Data Memory is accessed). ALE will retain its normal HIGH value during Idle mode and a LOW value during Power-down mode while in the ‘RFI reduction mode’.

Additionally during internal access (EA = 1) ALE will toggle normally when the address exceeds the internal Program Memory size. During external access (EA = 0) ALE will always toggle normally, whether the flag ‘RFI’ is set or not.

FREQUENCY

RANGE (MHZ)

TEMPERATURE

RANGE (°C)

SOT318-2 3.5 to 16 −40 to +85P83C557E8EFB/nnn

Notes

1. ROMless type.

2. ROM coded type; ‘nnn’ denotes the ROM code number.

3. EPROM/OTP type.

1999 Mar 12 4

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

4 BLOCK DIAGRAM

MHI023

XTAL4

XTAL3

PLL

'SECONDS'

OSCILLATOR

TIMER

(T3)

TIMER

WATCHDOG

RSTOUT EWCMSR0 to CMSR5

SDA SCL

ref(n)(A)

ref(p)(A)

ADC0 to ADC7

ADEXS

PWM0

PWM1

SSA

DDA

I/O

C-BUS

SERIAL

(6)

ADC

PWM

DUAL

RAM

256 bytes

DATA MEMORY

PROGRAM

1792 bytes

ROM/

MEMORY

64 kbytes

AUX-RAM

(7)

EPROM

P8xC557E8

8-bit internal bus

OUTPUT

SELECTION

COMPARATOR

WITH

16-BIT

THREE

COMPARATORS

16-BIT

EVENT

TIMER/

FOUR

16-BIT

CAPTURE

I/O

8-BIT

PORTS

REGISTERS

(T2)

COUNTER

LATCHES

(5)(2)(2)(4)(4)

CMT0, CMT1

RT2

handbook, full pagewidth

CT0I to CT3IP4P5RXDTXDP3P2P1P0

Fig.1 Block diagram P8xC557E8.

CPU

core

(T0,T1)

XTAL2

80C51

ALE

excluding

ROM/RAM

PSEN

T1 INT0 INT1

(4) (4) (4) (4)

SELXTAL

EVENT

TIMER/

COUNTERS

TWO 16 - BIT

RSTIN

XTAL1

1999 Mar 12 5

UART

PORT

SERIAL

EXT. BUS

PARALLEL

I/O PORTS

(3)

(4)

(1)

AD0 to AD7

A8 to A15

(1) Alternative function of Port 0.

(2) Alternative function of Port 1.

(3) Alternative function of Port 2.

(4) Alternative function of Port 3.

(5) Alternative function of Port 5.

(6) Alternative function of Port 6.

(7) Not present in P80C557E8.

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

5 FUNCTIONAL DIAGRAM

handbook, full pagewidth

alternative function

ADC0 ADC1 ADC2 ADC3 ADC4 ADC5 ADC6 ADC7

CMSR0 CMSR1 CMSR2 CMSR3 CMSR4 CMSR5

CMT0 CMT1

XTAL1 XTAL2

EA/V

PSEN

ALE/PROG

PWM0 PWM1

SDA

ADEXS

ref(p)(A)

ref(n)(A)

STADC

PORT 5

PORT 4

RSTIN

RSTOUT

SCL

SELXTAL1

XTAL4 XTAL3

0 1

(1)

0 1 2 3 4 5 6 7

P8xC557E8

MHI024

2 3 4 5 6 7

0 1 2 3 4 5 6 7

V V

SSA DDA SS DD

PORT 0

PORT 1

PORT 2

PORT 3

(2)

alternative function

AD0 AD1 AD2

LOW ORDER

AD3 AD4 AD5 AD6 AD7

CT0I/INT2 CT1I/INT3 CT2I/INT4 CT3I/INT5

A8 A9 A10 A11 A12 A13 A14 A15

RXD/DATA

TXD/CLOCK INT0

INT1 T0

T1 WR RD

T2 RT2

ADDRESS

AND

DATA BUS

HIGH ORDER

ADDRESS

BUS

(1) Only the P87C557E8 with an alternative function. (2) V

VDD/VSS- 4 digital supply pairs.

- 2 analog supply pairs;

DDA/VSSA

Fig.2 Functional diagram.

1999 Mar 12 6

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

6 PINNING INFORMATION

6.1 Pinning diagram

handbook, full pagewidth

P5.7/ADC7 P5.6/ADC6 P5.5/ADC5 P5.4/ADC4 P5.3/ADC3 P5.2/ADC2 P5.1/ADC1 P5.0/ADC0

ref(n)(A)

ref(p)(A)

SSA1

DDA1

V V

ADEXS

PWM0

SS1 DD1

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

XTAL4

SELXTAL1 80

XTAL3 78

SSA2VDDA2

P0.1/AD1

P0.0/AD0 75

P8xC557E8

P0.3/AD3

P0.2/AD2 73

P0.5/AD5

P0.4/AD4 71

P0.7/AD7

P0.6/AD6 69

SS4VDD4

V 67

(1)

EA/V 65

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

ALE/PROG PSEN P2.7/A15 P2.6/A14

P2.5/A13

P2.4/A12 P2.3/A11 P2.2/A10

P2.1/A9 P2.0/A8

SS3

DD3 XTAL1 XTAL2 n.c. n.c.

(1)

PWM1

EW P4.0/CMSR0 P4.1/CMSR1 P4.2/CMSR2 P4.3/CMSR3

RSTOUT

P4.4/CMSR4

(1) Only the P87C557E8 with this alternative function.

19 20 21 22 23 24

P4.6/CMT0

P4.5/CMSR5

DD2

P4.7/CMT1

SS2

RSTIN

P1.0/CT0I/INT2

Fig.3 Pin configuration QFP80/SOT318 version.

1999 Mar 12 7

P1.1/CT1I/INT3

P1.2/CT2I/INT4

P1.3/CT3I/INT5

P1.4/T2

P1.5/RT2

P1.6

P1.7

SCL

SDA

48 47 46 45 44 43 42 41

P3.7/RD P3.6/WR P3.5/T1 P3.4/T0 P3.3/INT1 P3.2/INT0 P3.1/TXD P3.0/RXD

MHI025

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

6.2 Pin description Table 1 Pin description for QFP80 (SOT318-2)

To avoid a ‘latch-up’ effect at power-on: VSS− 0.5 V < ‘voltage at any pin at any time’ < VDD+ 0.5 V.

SYMBOL PIN DESCRIPTION

ref(n)(A)

ref(p)(A)

SSA1

DDA1

P5.7/ADC7 to P5.0/ADC0

to V

SS1

DD1

to V

SS4

DD4

ADEXS 15 Start ADC operation. Input starting ADC, triggered by a programmable edge; ADC

PWM0 16 Pulse Width Modulation output 0. PWM1 17 Pulse Width Modulation output 1. EW 18 Enable Watchdog Timer (WDT): enable for T3 Watchdog Timer and disable

P4.0/CMSR0 to P4.5/CMSR5

P4.6/CMT0 to P4.7/CMT1

RSTOUT 23 Reset output of the P8xC557E8 for resetting peripheral devices during initialization

RSTIN 30 Reset input to reset the P8xC557E8. P1.0/CT0I/INT2 to

P1.3/CT3I/INT5 P1.4/T2 to

P1.5/RT2 P1.6 to P1.7 37 to 38 SCL 39 I2C-bus serial clock I/O port. If SCL is not used, it must be connected to VSS. SDA 40 I2C-bus serial data I/O port. If SDA is not used, it must be connected to VSS. P3.0/RXD 41 Port 3 (P3.0 to P3.7): 8-bit quasi-bidirectional I/O port lines; P3.1/TXD 42 P3.2/INT0 43 P3.3/INT1 44 P3.4/T0 45 P3.5/T1 46 P3.6/WR 47 P3.7/RD 48 n.c. 49, 50 Not connected pins.

1 Low-end of ADC reference resistor. 2 High-end of ADC reference resistor. 3 Ground, analog part. For ADC receiver and reference voltage. 4 Power supply, analog part (+5 V). For ADC receiver and reference voltage. 5to12 Port 5 (P5.7 to P5.0): 8-bit input port lines;

ADC7 to ADC0: 8 input channels to the ADC.

13, 29, 54, 67

14, 28, 53, 66

Ground; digital part; circuit ground potential. V V

is internally connected to digital ground, but should be connected externally.

SS3

SS1

, V

SS2

, V

must be connected,

SS4

Power supply, digital part (+5 V). Power supply pins during normal operation and power reduction modes. All pins must be connected.

operation can also be started by software. This pin must not ﬂoat.

Power-down mode. This pin must not ﬂoat.

19 to 22, 24, 25

26, 27

Port 4 (P4.0 to P4.7): 8-bit quasi-bidirectional I/O port lines; CMSR0 to CMSR5: compare and set/reset outputs for Timer T2; CMT0 to CMT1: compare and toggle outputs for Timer T2.

and Watchdog Timer overﬂow.

31 to 34 Port 1 (P1.0 to P1.7): 8-bit quasi-bidirectional I/O port lines;

CT0I to CT3I: Capture timer inputs for Timer T2;

35, 36

INT2 to INT5: external interrupts 2 to 5; T2: T2 event input (rising edge triggered); RT2: T2 timer reset input (rising edge triggered).

RXD: Serial input port; TXD: Serial output port; INT0: External interrupt input 0; INT1: External interrupt input 1; T0: Timer 0 external interrupt input; T1: Timer 1external interrupt input; WR: External Data Memory Write strobe; RD: External Data Memory Read strobe.

1999 Mar 12 8

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

SYMBOL PIN DESCRIPTION

XTAL2 51 Crystal pin 2: output of the inverting ampliﬁer that forms the oscillator.

Left open-circuit when an external oscillator clock is used.

XTAL1 52 Crystal pin 1: input to the inverting ampliﬁer that forms the oscillator, and input to the

internal clock generator. Receives the external oscillator clock signal when an external oscillator is used. Must be connected to logic HIGH if the PLL oscillator is selected (SELXTAL1 = LOW).

P2.0/A08 to P2.7/A15

PSEN 63 Program Store Enable output: read strobe to the external Program Memory via

ALE/PROG 64 Address Latch Enable output. Latches the low byte of the address during access of

EA/V

P0.7/AD7 to P0.0/AD0

DDA2

SSA2

XTAL3 78 Crystal pin 3: output of the inverting ampliﬁer that forms the 32 kHz oscillator. XTAL4 79 Crystal pin 2: input to the inverting ampliﬁer that forms the 32 kHz oscillator. XT AL3 is

SELXTAL1 80 SELXTAL1 = HIGH, selects the HF oscillator, using the XTAL1/XTAL2 crystal.

55 to 62 Port 2 (P2.0 to P2.7): 8-bit quasi-bidirectional I/O port lines;

A08 to A15: High-order address byte for external memory.

Ports 0 and 2. Is activated twice each machine cycle during fetches from external Program Memory . When executing out of externalProgram Memory two activations of PSEN are skipped during each access to external Data Memory. PSEN is not activated (remains HIGH) during no fetches from external Program Memory. PSEN can sink/source 8 LSTTL inputs. It can drive CMOS inputs without external pull-ups.

external memory in normal operation. It is activated every six oscillator periods except during an external Data Memory access. ALE can sink/source 8 LSTTL inputs. It can drive CMOS inputs without an external pull-up. To prohibit the toggling of ALE pin (RFI noise reduction) the bit RFI (SFR: PCON.5) must be set by software; see Section 2.2. PROG: the programming pulse input; alternative function for the P87C557E8.

65 External Access input. If, during reset, EA is held at a TTL level HIGH the CPU

executes out of the internal Program Memory. If, during reset, EA is held at a TTL level LOW the CPU executes out of external Program Memory via Port 0 and Port 2. EA is not allowed to ﬂoat. EA is latched during reset and don’t care after reset.

VPP: the programming supply voltage; alternative function for the P87C557E8.

68 to 75 Port 0 (P0.7 to P0.0): 8-bit open-drain bidirectional I/O port lines;

AD7 to AD0: Multiplexed Low-order address and Data bus for external memory.

76 Power supply, analog part (+5 V). For PLL oscillator. 77 Ground, analog part. For PLL oscillator.

pulled LOW if the PLL oscillator is not selected (SELXTAL1 = 1) or if reset is active.

If SELXTAL1 = LOW the PLL is selected for clocking of the controller, using the XTAL3/XTAL4 crystal.

1999 Mar 12 9

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

7 FUNCTIONAL DESCRIPTION

The P8xC557E8 is a stand-alone high-performance microcontroller designed for use in real time applications such as instrumentation, industrial control, medium to high-end consumer applications and specific automotive control applications.

In addition to the 80C51 standard functions, the device provides a number of dedicated hardware functions for these applications.

The P8xC557E8 is a control-oriented CPU with on-chip program and Data Memory, but it cannot be extended with external Program Memory. It can access up to 64 kbytes of external Data Memory. For systems requiring extra capability, the P8xC557E8 can be expanded using standard memories and peripherals.

The functional description of the device is described in:

Chapter 8 “Memory organization” Chapter 9 “I/O facilities” Chapter 10 “Pulse Width Modulated outputs” Chapter 11 “Analog-to-Digital Converter (ADC)” Chapter 12 “Timers/counters” Chapter 13 “Serial I/O ports” Chapter 14 “Interrupt system” Chapter 15 “Reduced power modes” Chapter 16 “Oscillator circuits” Chapter 17 “Reset circuitry”.

1999 Mar 12 10

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

8 MEMORY ORGANIZATION

The Central Processing Unit (CPU) manipulates operands in three memory spaces; these are the 64 kbytes external Data Memory, 2048 bytes internal Data Memory (consisting of 256 bytes standard RAM and 1792 bytes AUX-RAM) and the 64 kbytes internal or 64 kbytes external Program Memory (see Fig.4).

8.1 Program Memory

The Program Memory of the P8xC557E8 consists of 64 kbytes ROM or 64 kbytes EPROM. If, during reset, the EA pin was held HIGH, the P8xC557E8 always executes out of the internal Program Memory. If the EA pin was held LOW during reset the P8xC557E8 fetches all instructions from the external Program Memory. The EA input is latched during reset and is don’t care after reset.

The internal Program Memory content is protected by setting a mask programmable security bit (ROM) or by the software programmable security bits (EPROM) respectively, i.e. it cannot be read out at any time by any test mode or by any instruction in the external Program Memory space. The MOVC instructions are the only ones which have access to program code in the internal or external Program Memory. The EA input is latched during reset and is don’t care after reset. This implementation prevents from reading internal program code by switching from external Program Memory to internal Program Memory during MOVC instruction or an instruction that handles immediate data. Table 2 lists the access to the internal and external Program Memory with MOVC instructions whether the security feature has been activated or not.

Due to the maximum size of the internal Program Memory, the MOVC instructions can always operate either in the internal or in the external Program Memory.

Table 2 Memory access by the MOVC instruction For code protection of the P87C557E8 see Section 23.2.

8.2 Internal Data Memory

The internal Data Memory is divided into three physically separated parts: 256 bytes of RAM, 1792 bytes of AUX-RAM, and a 128 bytes Special Function Registers (SFRs) area. These parts can be addressed each in a different way as described in Sections 8.2.1 to 8.2.2 and Table 3.

Table 3 Internal Data Memory map

MEMORY LOCATION ADDRESS MODE

RAM 0 to 127 Direct and indirect

128 to 255 Indirect only SFR 128 to 255 Direct only AUX-RAM 0 to 1791 Indirect only with MOVX

8.2.1 RAM

• RAM 0 to 127 can be addressed directly and indirectly as in the 80C51. Address pointers are R0 and R1 of the selected register bank.

• RAM 128 to 255 can only be addressed indirectly. Address pointers are R0 and R1 of the selected register bank.

Four register banks, each 8 registers wide, occupy locations 0 through 31 in the lower RAM area. Only one of these banks may be enabled at a time. The next 16 bytes, locations 32 through 47, contain 128 directly addressable bit locations. The stack can be located anywhere in the internal 256 bytes RAM. The stack depth is only limited by the available internal RAM space of 256 bytes (see Fig.6). All registers except the Program Counter and the four register banks reside in the Special Function Register address space.

8.2.2 SPECIAL FUNCTION REGISTERS

The Special Function Registers can only be addressed directly in the address range from 128 to 255 (see Fig.7).

MOVC

INSTRUCTION

MOVC in internal Program Memory

MOVC in external Program Memory

Note

1. Not applicable due to 64 kbytes internal Program Memory.

1999 Mar 12 11

PROGRAM MEMORY ACCESS

INTERNAL EXTERNAL

YES NO

(1)

YES

8.2.3 AUX-RAM

• AUX-RAM 0 to 1791 is indirectly addressable via page register (XRAMP) and MOVX-Ri instructions, unless it is disabled by setting ARD = 1 (see Fig.5). When executing from internal Program Memory, an access to AUX-RAM 0 to 1791 will not affect the ports P0, P2, P3.6 and P3.7.

• AUX-RAM 0 to 1791 is also indirectly addressable as external Data Memory locations 0 to 1791 via MOVX-Ri instructions, unless it is disabled by setting ARD = 1.

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

An access to external Data Memory locations higher than 1791 will be performed with the MOVX @DPTR instructions in the same way as in the 80C51 structure, so with P0 and P2 as data/address bus and P3.6 and P3.7 as write and read timing signals.

Note that the external Data Memory cannot be accessed with R0 and R1 as address pointer if the AUX-RAM is enabled (ARD = 0, default).

Table 4 AUX-RAM Page Register (address FAH)

76543210

XRAMPx XRAMPx XRAMPx XRAMPx XRAMPx XRAMP2 XRAMP1 XRAMP0

Table 5 Description of XRAMP bits

BIT SYMBOL FUNCTION

7 to 3 XRAMPx Reserved for future use. During read XRAMPx = undeﬁned; a write

operation must write logic 0s to these locations.

2 to 0 XRAMP2 to XRAMP0 AUX-RAM page select bits 2 to 0; see Table 6.

Table 6 Memory locations for all possible MOVX-accesses X = don’t care.

(1)

ARD

XRAMP2 XRAMP1 XRAMP0 MEMORY LOCATIONS

8.2.4 AUX-RAM PAGE REGISTER (XRAMP)

The AUX-RAM Page Register is used to select one of seven 256-bytes pages of the internal 1792 bytes AUX-RAM for MOVX-accesses via R0 or R1. Its reset value is ‘XXXXX000B’.

MOVX @Ri,A and MOVX A,@Ri instructions access

0 0 0 0 AUX-RAM locations 0 to 255 (reset condition) 0 0 0 1 AUX-RAM locations 256 to 511 0 0 1 0 AUX-RAM locations 512 to 767 0 0 1 1 AUX-RAM locations 768 to 1023 0 1 0 0 AUX-RAM locations 1024 to 1279 0 1 0 1 AUX-RAM locations 1280 to 1535 0 1 1 0 AUX-RAM locations 1536 to 1791 0 1 1 1 No valid memory access; reserved for future use 1 X X X External RAM locations 0 to 255

MOVX @DPTR,A and MOVX A,@DPTR instructions access

0 X X X AUX-RAM locations 0 to 1791 (reset condition);

External RAM locations 1792 to 65535

1 X X X External RAM locations 0 to 65535

Note

1. ARD: AUX-RAM disable, is a bit in SFR PCON (bit PCON.6); see Section 15.5.

1999 Mar 12 12

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

andbook, full pagewidth

64 kbytes

64 kbytes 64 kbytes

INTERNAL

(EA = 1)

PROGRAM MEMORY

handbook, full pagewidth

EXTERNAL

(EA = 0)

MOVX @Ri, A MOVX A, @Ri

OVERLAPPED SPACE

255

INDIRECT ONLY

127

DIRECT AND

INDIRECT

MAIN RAM

SPECIAL

FUNCTION

REGISTERS

INTERNAL DATA

MEMORY

AUXILIARY

RAM

(ARD = 0)

1792 bytes

1791

EXTERNAL DATA

(ARD = 1)

MEMORY

MBH077

Fig.4 Memory map and address space.

255 1791

(XRAMP) = 06 H

255

(XRAMP) = 05 H

255

(XRAMP) = 04 H

255

(XRAMP) = 03 H

255

(XRAMP) = 02 H

255

(XRAMP) = 01 H

255

(XRAMP) = 00 H

1536 1535

1280 1279

1024 1023

768 767

512 511

256 255

MOVX @DPTR, A MOVX A, @DPTR

MBH078

Fig.5 Indirect addressing AUX-RAM (1792 bytes); ARD = 0 (bit PCON.6).

1999 Mar 12 13

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

8.3 Addressing

The P8xC557E8 has five methods for addressing:

• Register

• Direct

• Register-Indirect

• Immediate

• Base-Register plus Index-Register-Indirect.

The first three methods can be used for addressing destination operands. Most instructions have a ‘destination/source’ field that specifies the data type, addressing methods and operands involved. For operations other than MOVs, the destination operand is also a source operand.

Access to memory addresses is as follows:

• Register in one of the four register banks through Register, Direct or Register-Indirect addressing.

• Internal RAM (2048 bytes) through Direct or Register-Indirect addressing.

– Internal RAM: bytes 0 to 127; may be addressed

directly/indirectly.

– Internal RAM: bytes 128 to 255; share their address

location with the SFRs and so may only be addressed indirectly as data RAM.

– AUX-RAM: bytes 0 to 1791; can only be addressed

indirectly via MOVX.

• Special Function Registers through direct addressing at address locations 128 to 255 (see Fig.7).

• External Data Memory through Register-Indirect addressing.

• Program Memory look-up tables through Base-Register plus Index-Register-Indirect addressing.

BYTE

ADDRESS

(HEX)

FFH

2FH 2EH 2DH 2CH 2BH 2AH

29H 28H 27H 26H 25H 24H 23H 22H 21H 20H

1FH

18H 17H

10H 0FH

08H 07H

00H

BIT ADDRESS

(HEX)

(MSB) (LSB)

7F 7E 7D 7C 7B 7A 79 78 77 76 75 74 73 72 71 70 6F 6E 6D 6C 6B 6A 69 68 67 66 65 64 63 62 61 60 5F 5E 5D 5C 5B 5A 59 58 57 56 55 54 53 52 51 50 4F 4E 4D 4C 4B 4A 49 48 47 46 45 44 43 42 41 40 3F 3E 3D 3C 3B 3A 39 38 37 36 35 34 33 32 31 30 2F 2E 2D 2C 2B 2A 29 28 27 26 25 24 23 22 21 20 1F 1E 1D 1C 1B 1A 19 18 17 16 15 14 13 12 11 10 0F 0E 0D 0C 0B 0A 09 08 07 06 05 04 03 02 01 00

BANK 3

BANK 2

BANK 1

BANK 0

MBH079

BYTE

ADDRESS

(DECIMAL)

255

47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31

24 23

16 15

8 7

1999 Mar 12 14

Fig.6 Internal MAIN RAM bit addresses.

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

handbook, full pagewidth

BYTE ADDRESS

(HEX)

FFH

F8H

F0H F6 F5 F4 F3 F2 F1 F0

F8H EE ED EC EB EA E9 E8

E0H E6 E5 E4 E3 E2 E1 E0

D8H

D0H

C8H

C0H C6 C5 C4 C3 C2 C1 C0

B8H BE BD BC BB BA B9 B8

B0H B6 B5 B4 B3 B2 B1 B0

A8H AE AD AC AB AA A9 A8

BIT ADDRESS

(HEX)

(MSB) (LSB)

PT2 PCM2 PCM1 PCM0 PCT3 PCT2 PCT1 PCT0

FE FD FC FB FA F9 F8

ET2 ECM2 ECM1 ECM0 ECT3 ECT2 ECT1 ECT0

CR2 ENS1 STA STO SI AA CR1 CR0

DE DD DC DB DA D9 D8 CY AC F0 RS1 RS0 OV F1 P D7 D6 D5 D4 D3 D2 D1 D0

T2OV CMI2 CMI1 CMI0 CTI3 CTI2 CTI1 CTI0

CF CE CD CC CB CA C9 C8

- PAD PS1 PS0 PT1 PX1 PT0 PX0

B7 EA EAD ES1 ES0 ET1 EX1 ET0 EX0 AF

(MNEMONIC)

IP1

IEN1

ACC

S1CON

PSW

TM2IR

IP0

IEN0

A0H A6 A5 A4 A3 A2 A1 A0

SM0 SM1 SM2 REN TB8 RB8 TI RI

98H 9E 9D 9C 9B 9A 99 98

90H 96 95 94 93 92 91 90

88H 8E 8D 8C 8B 8A 89 88

80H 86 85 84 83 82 81 80

TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0

MBH456

Fig.7 Special Function Registers bit addresses.

S0CON

TCON

1999 Mar 12 15

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

9 I/O FACILITIES

The P8xC557E8 has six 8-bit ports. Ports 0 to 3 are the same as in the 80C51, with the exception of the additional functions of Port 1. The parallel I/O function of Port 4 is equal to that of Ports 1, 2 and 3. All ports are bidirectional with the exception of Port 5 which is only a parallel input port.

Ports 0, 1, 2, 3, 4 and 5 perform the following alternative functions:

Port 0 Provides the multiplexed low-order address and

data bus used for expanding the P8xC557E8 with standard memories and peripherals.

Port 1 Is used for a number of special functions:

• 4 capture inputs (or external interrupt request inputs if capture information is not utilized)

• external counter input

• external counter reset input.

Port 2 Provides the high-order address bus when the

P8xC557E8 is expanded with external Data Memory and / or the P8xC557E8 executes from external Program Memory.

Port 3 Pins can be configured individually to provide:

• External interrupt request inputs

• Counter inputs

• Receiver input and transmitter output of serial

port SIO 0 (UART)

• Control signals to read and write external Data Memory.

Port 4 Can be configured to provide signals indicating a

match between timer/counter T2 and its compare registers.

Port 5 May be used in conjunction with the ADC interface.

Unused analog inputs can be used as digital inputs. As Port 5 lines may be used as inputs to the ADC, these digital inputs have an inherent hysteresis to prevent the input logic from drawing too much current from the power lines when driven by analog signals. Channel-to-channel crosstalk should be taken into consideration when both digital and analog signals are simultaneously input to Port 5 (see Chapter 21).

A pin of which the alternative function is not used may be used as normal bidirectional I/O. The generation or use of a Port 1, Port 3 or Port 4 pin as an alternative function is carried out automatically by the P8xC557E8 provided the associated Special Function Register bit is set HIGH.

The SDA and SCL lines serve the serial port SI01 (I2C-bus). Because the I2C-bus may be active while the device is disconnected from VDD, these pins are provided with open-drain drivers.

Figure 8 shows the pull-up arrangements of Ports 1 to 4; Transistor ‘p1’ is turned on for 2 oscillator periods after Q makes a HIGH-to-LOW transition. During this time, ‘p1’ also turns on ‘p3’ through the inverter to form an additional pull-up.

handbook, full pagewidth

from port latch

read port pin

input data

2 oscillator

periods

strong pull-up

INPUT

BUFFER

Fig.8 I/O buffers in the P8xC557E8 (Port 1 to Port 4).

1999 Mar 12 16

I/O PIN

MLC926 - 1

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

10 PULSE WIDTH MODULATED OUTPUTS

The P8xC557E8 contains two Pulse Width Modulated (PWM) output channels (see Fig.9). These channels generate pulses of programmable length and interval. The repetition frequency is defined by an 8-bit prescaler PWMP, which supplies the clock for the counter. The prescaler and counter are common to both PWM channels. The 8-bit counter counts modulo 255, i.e., from 0 to 254 inclusive. The value of the 8-bit counter is compared to the contents of two registers: PWM0 and PWM1.

Provided the contents of either of these registers is greater than the counter value, the corresponding PWM0 or PWM1 output is set LOW. If the contents of these registers are equal to, or less than the counter value, the output will be HIGH. The pulse-width-ratio is therefore defined by the contents of the registers PWM0 and PWM1.

255

⁄

and

255

The pulse-width-ratio is in the range of0⁄ may be programmed in increments of1⁄

Buffered PWM outputs may be used to drive DC motors. The rotation speed of the motor would be proportional to the contents of PWMn. The PWM outputs may also be configured as a dual DAC.

In this application, the PWM outputs must be integrated using conventional operational amplifier circuitry. If the resulting output voltages have to be accurate, external buffers with their own analog supply should be used to buffer the PWM outputs before they are integrated.

The repetition frequency f

given by:

PWM

--------------------------------------------------------------2 PWMP 1+()× 255×

, at the PWMn outputs is

PWM

CLK

This gives a repetition frequency range of 123 Hz to

31.4 kHz (at f

= 16 MHz). By loading the PWM registers

clk

with either 00H or FFH, the PWM channels will output a constant HIGH or LOW level, respectively. Since the 8-bit counter counts modulo 255, it can never actually reach the value of the PWM registers when they are loaded with FFH.

When a compare register (PWM0 or PWM1) is loaded with a new value, the associated output is updated immediately. It does not have to wait until the end of the current counter period. Both PWMn output pins are driven by push-pull drivers. These pins are not used for any other purpose.

handbook, full pagewidth

PWM0

I N T

E R N A L

B U S

clk

PRESCALER

PWMP

8-BIT COMPARATOR

8-BIT COUNTER1/2

8-BIT COMPARATOR

PWM1

Fig.9 Functional diagram of Pulse Width Modulated outputs.

OUTPUT

BUFFER

OUTPUT

BUFFER

PWM0

PWM1

MGA154

1999 Mar 12 17

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

10.1 Prescaler Frequency Control Register (PWMP)

Reading PWMP gives the current reload value. The actual count of the prescaler cannot be read.

Table 7 Prescaler Frequency Control Register (address FEH)

76543210

PWMP.7 PWMP.6 PWMP.5 PWMP.4 PWMP.3 PWMP.2 PWMP.1 PWMP.0

Table 8 Description of PWMP bits

BIT SYMBOL DESCRIPTION

7 to 0 PWMP.7 to PWMP.0 Prescaler division factor. The Prescaler division factor = (PWMP) + 1.

10.2 Pulse Width Register 0 (PWM0) Table 9 Pulse width register (address FCH)

76543210

PWM0.7 PWM0.6 PWM0.5 PWM0.4 PWM0.3 PWM0.2 PWM0.1 PWM0.0

Table 10 Description of PWM0 bits

BIT SYMBOL DESCRIPTION

7 to 0 PWM0.7 to PWM0.0

10.3 Pulse Width Register 1 (PWM1) Table 11 Pulse width register (address FDH)

76543210

PWM1.7 PWM1.6 PWM1.5 PWM1.4 PWM1.3 PWM1.2 PWM1.1 PWM1.0

Table 12 Description of PWM1 bits

BIT SYMBOL DESCRIPTION

7 to 0 PWM1.7 to PWM1.0

Pulse width ratio.

LOW/HIGH ratio of PWM0 signals

Pulse width ratio.

LOW/HIGH ratio of PWM1 signals

PWM0()

----------------------------------------- 255 PWM0()–

PWM1()

----------------------------------------- 255 PWM1()–

1999 Mar 12 18

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

11 ANALOG-TO-DIGITAL CONVERTER (ADC)

11.1 ADC features

• 10-bit resolution

• 8 multiplexed analog inputs

• Programmable autoscan of the analog inputs

• Bit oriented 8-bit scan-select register to select analog

inputs

• Continuous scan or one time scan configurable from 1 to 8 analog inputs

• Start of a conversion by software or with an external signal

• Eight 10-bit buffer registers, one register for each analog input channel

• Interrupt request after one channel scan loop

• Programmable prescaler (dividing by 2, 4, 6, 8) to adapt

to different system clock frequencies

• Conversion time for one analog-to-digital conversion: 15 to 50 µs

• Differential non-linearity (DLe): ±1 LSB

• Integral non-linearity (ILe): ±2 LSB

• Offset error (OSe): ±2 LSB

• Gain error (Ge): ±4%

• Absolute voltage error (Ae): 3 LSB

• Channel-to-channel matching (M

): ±1 LSB

ctc

• Crosstalk between analog inputs (Ct): < 60 dB at 100 kHz

• Monotonic and no missing codes

• Separated analog (V

DDA,VSSA

) and digital (VDD,VSS)

supply voltages

• Reference voltage at two special pins: V V

ref(p)(A)

ref(n)(A)

and

For information on the ADC characteristics, refer to Chapter 21.

11.2 ADC functional description

The P8xC557E8 has a 10-bit successive approximation ADC with 8 multiplexed analog input channels, comprising a high input impedance comparator, DAC (built with 1024 series resistors and analog switches), registers and control logic. Input voltage range is from V (typical 0 V) to V

ref(p)(A)

(typical +5 V).

ref(n)(A)

Each of the set of 8 buffer registers (10-bit wide) store the conversion results of the proper analog input channel.

Eleven Special Function Registers (SFRs) perform the user software interface to the ADC; see Table 14 for an overview of the ADC SFRs. In order to have a minimum of ADC service overhead in the microcontroller program, the ADC is able to operate autonomously within its user configurable autoscan function.

Figure 10 shows the functional diagram of the ADC.

11.3 ADC timing

A programmable prescaler is controlled by the user selectable bits ADPR1 and ADPR0 in SFR ADCON to adapt the conversion time for different microcontroller clock frequencies.

Table 13 shows conversion times (t

ADC

) for one analog-to-digital conversion at some convenient system clock frequencies (f

) and ADC programmable prescaler

clk

divisors: m. Conversion time t

A conversion time t

=(6× m + 1) machine cycles.

ADC

consists of one sample time period

ADC

(which equals two bit conversion times), 10 bit conversion time periods and one machine cycle to store the result. After result storage an extra initializing time period follows to select the next analog input channel (according to the contents of SFR ADPSS), before the input signal is sampled.Thus the time period between two adjacent conversions within an autoscan loop is larger than the pure time t

. This autoscan cycle time is (7 × m) machine

ADC

cycles. At the start of an autoscan conversion the time between

writing to SFR ADCON and the first analog input signal sampling depends on the current prescaler value (m) and the relative time offset between this write operation and the internal (divided) ADC clock. This gives a variation range for the analog-to-digital conversion start time of (1⁄2× m) machine cycles.

Table 13 Conversion time conﬁguration examples

ADC

(µs) at f

CLK

6 MHz 8 MHz 12 MHz 16 MHz

2 26.00 19.50 13.00

(1)

9.75

(1)

4 50.00 37.50 25.00 18.75 6 74.00 8 98.00

(1) (1)

55.50

73.50

(1) (1)

37.00 27.75

49.00 36.75

Note

1. Prohibited t

15 µs ≤ t

values; for t

ADC

≤ 50 µs, the specified ADC

ADC

outside the limits of

characteristics are not guaranteed.

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Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

handbook, full pagewidth

COMPARATOR

ADC0

ADC7

ref(p)(A)

ref(n)(A)

DDA1

SSA1

ANALOG

MULTIPLEXER

DAC

SAR

ADEXS

SCAN LOGIC

ADPSS

Read ADRSH

INTERNAL BUS

Fig.10 Functional diagram of ADC.

11.4 ADC conﬁguration and operation

Every analog-to-digital conversion is an autoscan conversion. The two user selectable general operation modes are continuous scan and one-time scan mode.

The desired analog input port channel(s) for conversion is(are) selected by programming analog-to-digital input port scan-select bits in SFR ADPSS. An analog input channel is included in the autoscan loop if the corresponding bit in SFR ADPSS is logic 1, a channel is skipped if the corresponding bit in SFR ADPSS is logic 0.

An autoscan is always started according to the lowest bit position of SFR ADPSS that contains a logic 1.

An autoscan conversion is started by setting the flag ADSST in register ADCON either by software or by an external start signal at input pin ADEXS, if enabled.

8 x 10-BIT RESULT

REGISTERS

2 LATCHESADCON

Read ADRSLn

MBH080

Either no edge (external start totally disabled), a rising edge or/and a falling edge of ADEXS is selectable for external conversion start by the bits ADSRE and ADSFE in register ADCON.

After completion of an analog-to-digital conversion the 10-bit result is stored in the corresponding 10-bit buffer register. Then the next analog input is selected according to the next higher set bit position in ADPSS, converted and stored, and so on.

When the result of the last conversion of this autoscan loop is stored, the ADC interrupt flag ADINT (SFR ADCON), is set. It is not cleared by interrupt hardware - it must be cleared by software.

1999 Mar 12 20

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

In continuous scan mode (ADCSA = 1; ADCON.2) the ADC start and status flag ADSST (ADCON.3) retains the set state and the autoscan loop restarts from the beginning. In one-time scan mode (ADCSA = 0) conversions stop after the last selected analog input was converted, ADINT (ADCON.4) is set and ADSST is cleared automatically.

ADSST cannot be set (neither externally nor by software) as long as ADINT = 1, i.e. as long as ADINT is set, a new conversion start - by setting flag ADSST - is inhibited; actually it is only delayed until ADINT is cleared. If a logic 1 is written to ADSST while ADINT = 1, this new value is internally latched and preserved, not setting ADSST until ADINT = 0. In this state, a read of SFR ADCON will display ADSST = 0, because always the effective ADC status is read.

Note that under software control the analog inputs can also be converted in arbitrary order, when one-time scan mode is selected and in SFR ADPSS only one bit is set at a time. In this case ADINT is set and ADSST is cleared after every conversion.

11.5 ADC during Idle and Power-down mode

The analog-to-digital converter is active only when the microcontroller is in normal operating mode. If the Idle or Power-down mode is activated, then the ADC is switched off and put into a power saving idle state - a conversion in progress is aborted, a previously set ADSST flag is cleared and the internal clock is halted. The conversion result registers are not affected.

The interrupt flag ADINT will not be set by activation of Idle or Power-down mode. A previously set flag ADINT will not be cleared by the hardware. (Note: ADINT cannot be cleared by hardware at all, except for a reset - it must be cleared by the user software.)

After a wake-up from Idle or Power-down mode a set flag ADINT indicates that at least one autoscan loop was finished completely before the microcontroller was put into the respective power reduction mode and it indicates that the stored result data may be fetched now - if desired.

For further information on Idle and Power-down modes, refer to Chapter 15.

11.6 ADC resolution and characteristics

The ADC system has its own analog supply pins V and V

. It is referenced by two special reference

SSA1

DDA1

voltage input pins sourcing the resistance ladder of the DAC: V and V

ref(n)(A)

ref(p)(A)

and V

. The voltage between V

ref(n)(A)

defines the full-scale range. Due to the 10-bit

ref(p)(A)

resolution the full scale range is divided into 1024 unit steps.

The unit step voltage is 1 LSB, which is typically 5 mV (V

ref(p)(A)

= 5.12 V, V

ref(n)(A)

=0 V=V

SSA1

The DAC's resistance ladder has 1023 equally spaced taps, separated by a unit resistance ‘R’.

The first tap is located 0.5 × R above V is located 1.5 × R below V

. This results in a total

ref(p)(A)

ref(n)(A)

, the last tap

ladder resistance of 1024 × R. This structure ensures that the DAC is monotonic and results in a symmetrical quantization error. For input voltages between:

• V

ref(n)(A)

and [V

+1⁄2× LSB] the 10-bit conversion

ref(n)(A)

result code will be 0000000000B (= 000H or 0D)

• [V

−3⁄2× LSB] and V

ref(p)(A)

the 10-bit conversion

ref(p)(A)

result code will be 1111111111B (= 3FFH or 1023D).

The result code corresponding to an analog input voltage (V

) can be calculated from the formula:

in(A)

–

Result code 1024

in(A)Vref(n)(A)

×=

----------------------------------------------- V

–

ref(p)(A)Vref(n)(A)

The analog input voltage should be stable when it is sampled for conversion. At any times the input voltage slew rate must be less than 10 V/ms (5 V conversion range) in order to prevent an undefined result. This maximum input voltage slew rate can be ensured by an RC low pass filter with R = 2.2 kΩ and C = 100 nF. The capacitor between analog input pin and analog ground pin shall be placed close to the pins in order to have maximum effect in minimizing input noise coupling.

11.7 ADC after reset

After a reset of the microcontroller the ADCON and ADPSS registers are initialized to zero. Registers ADRSLn and ADRSH are not initialized by a reset.

1999 Mar 12 21

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

11.8 ADC Special Function Registers Table 14 ADC Special Function Registers overview

The SFRs are not bit addressable. For more information on Special Function Registers refer to Section 8.2.

ADDRESS NAME R/W

86H ADRSL0 R − ADC Result Registers Low Byte: ADRSL0 to ADRSL7; The read value 96H ADRSL1 A6H ADRSL2 B6H ADRSL3 C6H ADRSL4 D6H ADRSL5 E6H ADRSL6 F6H ADRSL7 F7H ADRSH R 00H ADC Result Register High Bits: one common result SFR for the upper

E7H ADPSS R/W 00H ADC Input Port Scan-Select Register. Contains control bits to select the

D7H ADCON R/W 00H ADC Control Register. Contains control and status bits for the

C7H P5 R − Digital Input Port Register; shared with analog inputs. P5 is not affected by

11.8.1 ADC RESULT REGISTERS The binary result code of the analog-to-digital conversions is accessed by the ADC Result Registers:

• ADRSLn (ADRSL0 to ADRSL7); eight input channel related conversion result SFRs for the 8 result lower bytes. Each of ADRSLn is associated with the indexed analog input channel ADCn (ADC0/P5.0 to ADC7/P5.7).

• ADRSH for the ADC; one general SFR for the 2 result upper bits (bit 9 and 8).

RESET

VALUE

DESCRIPTION

after reset is indeterminate. Their data are not affected by chip reset.

2 result bits.

analog input channel(s) to be scanned for analog-to-digital conversion.

analog-to-digital converter peripheral block.

chip reset.

During read (by software) of the ADRSLn register, simultaneously the two highest bits of the 10-bit conversion result are copied into the two latches, ADRSH.0 and ADRSH.1 (SFR ADRSH) preserving them until the next read of any ADRSLn register. Thus to ensure that the 10-bit result of the same single analog-to-digital conversion is captured, first read the ADRSLn register and then the ADRSH register.

Table 15 ADC Result Register Low Byte; ADRSLn; n = 0 to 7 (address see 86H to F6H)

76543210

ADRSn.7 ADRSn.6 ADRSn.5 ADRSn.4 ADRSn.3 ADRSn.2 ADRSn.1 ADRSn.0

Table 16 Description of ADRSLn bits

BIT SYMBOL DESCRIPTION

7 to 0 ADRSn.7 to ADRSn.0 ADC result lower byte.

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Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

Table 17 ADC Result Register High Bits; ADRSH (address F7H)

76543210

0 0 0 0 0 0 ADRSn.9 ADRSn.8

Table 18 Description of ADRSH bits

BIT SYMBOL DESCRIPTION

7to2 − The upper 6 bits ADRSH.2 to ADRSH.7 are always read as a logic 0. 1 to 0 ADRSn.9 to ADRSn.8 ADC result upper 2 bits.

11.8.2 ADC INPUT PORT SCAN-SELECT REGISTER (ADPSS)

Table 19 ADC Input Port Scan-Select Register (address E7H)

76543210

ADPSS7 ADPSS6 ADPSS5 ADPSS4 ADPSS3 ADPSS2 ADPSS1 ADPSS0

Table 20 Description of ADPSS bits

BIT SYMBOL DESCRIPTION

7 to 0 ADPSS7

ADPSS0

11.8.3 ADC C

Table 21 ADC Control Register (address D7H)

76543210

ADPR1 ADPR0 ADPOS ADINT ADSST ADCSA ADSRE ADSFE

Table 22 Description of ADCON bits

BIT SYMBOL DESCRIPTION

7 ADPR1 These two bits determine the value of the prescaler divisor (m); see Table 23. 6 ADPR0 5 ADPOS ADPOS is reserved for future use. Must be a logic 0 if ADCON is written. 4 ADINT ADC interrupt. This ﬂag is set when all selected analog inputs are converted (both in

ONTROL REGISTER (ADCON)

Control bits to select the analog input channel(s) to be scanned for analog-to-digital conversion. If all bits ADPSS0 to ADPSS7 = 0, then no conversion can be started. If ADPSS is written while an analog-to-digital conversion is in progress (ADSST = 1; ADCON.3) then the autoscan loop with the previous selected analog inputs is completed ﬁrst. The next autoscan loop is performed with the new selected analog inputs. For each individual bit position ADPSSn (n = 0 to 7):

• If ADPSSn = 0, then the corresponding analog input is skipped in the autoscan loop

• If ADPSSn = 1, then the corresponding analog input is included in the autoscan loop.

continuous scan and in one-time scan mode). An interrupt is invoked if this interrupt ﬂag is enabled. ADINT must be cleared by software. It cannot be set by software.

1999 Mar 12 23

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

BIT SYMBOL DESCRIPTION

3 ADSST ADC start and status. Setting this bit by software or by hardware (via ADEXS input)

starts the analog-to-digital conversion of the selected analog inputs. ADSST stays a logic 1 in continuous scan mode. In one-time scan mode, ADSST is cleared by hardware when the last selected analog input channel has been converted. As long as ADSST = 1, new start commands to the ADC-block are ignored. An analog-to-digital conversion in progress is aborted if ADSST is cleared by software.

2 ADCSA ADCSA =1 results in a continuous scan of the selected analog inputs after a start of an

analog-to-digital conversion. ADCSA = 0 results in an one-time scan of the selected analog inputs after a start of an analog-to-digital conversion.

1 ADSRE If ADSRE = 1, then a rising edge at input ADEXS will start the analog-to-digital

conversion and generate a capture signal. If ADSRE = 0, then a rising edge at input ADEXS has no effect.

0 ADSFE If ADSFE = 1, then a falling edge at input ADEXS will start the analog-to-digital

conversion and generate a capture signal. If ADSFE = 0, then a falling edge at input ADEXS has no effect.

Table 23 Prescaler selection

ADPR1 ADPR0 PRESCALER DIVISOR (m)

0 0 2 (default by reset) 01 4 10 6 11 8

11.8.4 DIGITAL INPUT PORT REGISTER (P5)

Digital Input Port Register (P5) is shared with analog inputs. P5 is not affected by chip reset. SFR P5 always represents the binary value of the logic level at input pins P5.0/ADC0 to P5.7/ADC7. Reading P5 does not affect analog-to-digital conversions. But it is recommended to use the digital input port function of the hardware Port 5 only as an alternative to analog input voltage conversions. Simultaneous mixed operation is discouraged to guarantee a reliable and accurate ADC result. For more information on P5 refer to Chapter 9.

Table 24 Digital Input Port Register (address C7H)

76543210

P5.7 P5.6 P5.5 P5.4 P5.3 P5.2 P5.1 P5.0

Table 25 Description of P5 bits

BIT SYMBOL DESCRIPTION

7 to 0 P5.7 to P5.0 Binary value of the logic level at input pins P5.0/ADC0 to P5.7/ADC.7.

1999 Mar 12 24

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

12 TIMERS/COUNTERS

The P8xC557E8 contains,

• Three 16-bit timer/event counters: Timer 0, Timer 1 and Timer T2

• One 8-bit timer, T3.

12.1 Timer 0 and Timer 1

Timer 0 and Timer 1 may be programmed to carry out the following functions:

• Measure time intervals and pulse durations

• Count events

• Generate interrupt requests.

Timers 0 and 1 each have a control bit in SFR TMOD that selects the timer or counter function of the corresponding timer.

In the timer function, the register is incremented every machine cycle. Thus, one can think of it as counting machine cycles. Since a machine cycle consists of 12 oscillator periods, the count rate is1⁄12× the oscillator frequency.

In the counter function, the register is incremented in response to a HIGH-to-LOW transition at the corresponding external input pin, T0 or T1. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a HIGH in one cycle and a LOW in the next cycle, the counter is incremented. Thus, it takes two machine cycles (24 oscillator periods) to recognize a HIGH-to-LOW transition. There are no restrictions on the duty cycle of the external input signal. To ensure that a given level is sampled at least once before it changes, it should be held for at least one full machine cycle.

Timer 0 and Timer 1 can be programmed independently to operate in one of four modes:

Mode 0 8-bit timer or 8-bit counter each with divide-by-32

prescaler. Mode 1 16-bit time-interval or event counter. Mode 2 8-bit time-interval or event counter with automatic

reload upon overflow. Mode 3 Timer 0: one 8-bit time-interval or event counter

and one 8-bit time-interval counter.

Timer 1: stopped. When Timer 0 is in Mode 3, Timer 1 can be programmed

to operate in Modes 0, 1 or 2 but cannot set an interrupt request flag or generate an interrupt. However, the overflow from Timer 1 can be used to pulse the serial port baud rate generator. With a 16 MHz crystal, the counting frequency of these timers/counters is as follows:

• In the timer function, the timer is incremented at a

frequency of 1.33 MHz (1⁄12× the system clock frequency)

• When programmed for external inputs: 0 to 660 kHz

(1⁄24× the system clock frequency).

Both internal and external inputs can be gated to the counter by a second external source for directly measuring pulse durations. When configured as a counter, the register is incremented on every falling edge on the corresponding input pin T0 or T1. The earliest moment, the incremented register value can be read is during the second machine cycle following the machine cycle within which the incrementing pulse occurred.

The counters are started and stopped under software control. Each one sets its interrupt request flag when it overflows from all HIGHs to all LOWs (or automatic reload value), with the exception of Mode 3 as previously described.

1999 Mar 12 25

Philips Semiconductors Product speciﬁcation

8-bit microcontroller P8xC557E8

12.1.1 TIMER/COUNTER MODE CONTROL REGISTER (TMOD)

Table 26 Timer/Counter Mode Control Register (address 89H)

76543210

GATE C/T M1 M0 GATE C/T M1 M0

Table 27 Description of TMOD bits for Timer 1 and Timer 0 Timer 0: bit TMOD.0 to TMOD.3; Timer 1: bit TMOD.4 to TMOD.7; n = 0, 1.

BIT SYMBOL DESCRIPTION

7 and 3 GATE Gating control. When set T imer/counter ‘n’ is enabled only while

control bit TRn (TR1 or TR0) is set. When cleared Timer ‘n’ is enabled whenever TRn control bit is set.

6 and 2 C/T Timer or Counter Selector. Cleared for Timer operation; input from internal system

clock. Set for Counter operation; input from pin Tn (T1 or T0). 5 and 1 M1 Timer 0, Timer 1 mode select; see Table 28. 4 and 0 M0

INTn pin is HIGH and

Table 28 Timer 0, Timer 1 mode select

M1 M0 OPERATING

0 0 Timer TL0/TL1 serves as 5-bit prescaler. 0 1 16-bit Timer/Counter TH0/TH1 and TL0/TL1 are cascaded; there is no prescaler. 1 0 8-bit auto-reload Timer/Counter TH0/TH1 holds a value which is to be reloaded into

TL0/TL1 each time it overﬂows.

1 1 Timer 0: TL0 is an 8-bit Timer/Counter controlled by the standard Timer 0 control bits.

TH0 is an 8-bit timer only controlled by Timer 1 control bits.

1 1 Timer 1: Timer/Counter 1 stopped.

12.1.2 T

Table 29 Timer/Counter Control Register (address 88H)

Table 30 Description of TCON bits

IMER/COUNTER CONTROL REGISTER (TCON)

76543210

TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0

BIT SYMBOL DESCRIPTION

7 and 5 TF1 and TF0 Timer 1 and Timer 0 overﬂow ﬂag. Set by hardware on Timer/Counter overﬂow.

Cleared by hardware when processor vectors to interrupt routine.

6 and 4 TR1 and TR0 Timer 1 and Timer 0 run control bit. Set/cleared by software to turn Timer/Counter

on/off.

3 and 1 IE1 and IE0 Interrupt 1 and Interrupt 0 edge ﬂag. Set by hardware when external interrupt edge

detected. Cleared when interrupt processed.

2 and 0 IT1 and IT0 Interrupt 1 and Interrupt 0 type control bit. Set/cleared by software to specify falling

edge/low level triggered external interrupts.

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