• enCoRe™ USB - enhanced Component Reduction
— Internal oscillator eliminates the need for an external
crystal or resonator
— Interface can auto-configure to operate as PS/2 or
USB without the need for external components to
switch between modes (no General Purpose I/O
[GPIO] pins needed to manage dual mode capability)
— Internal 3.3V regulator for USB pull-up resistor
— Configurable GPIO for real-world interface without
external components
• Flexible, cost-effective solution for applications that
combine PS/2 and low-speed USB, such as mice, gamepads, joysticks, and many others.
• USB Specification Compliance
— Conforms to USB Specification, Version 2.0
— Conforms to USB HID Specification, Version 1.1
— Supports one low-speed USB device address and
three data endpoints
— Integrated USB transceiver
— 3.3V regulated output for USB pull-up resistor
— 6-MHz external ceramic resonator or internal clock
mode
— 12-MHz internal CPU clock
— Internal memory
— 256 bytes of RAM
— 8 Kbytes of EPROM
— Interface can auto-configure to operate as PS/2 or
USB
— No external components for switching between PS/2
and USB modes
— No GPIO pins needed to manage dual mode
capability
• I/O ports
— Up to 16 versatile GPIO pins, individually
configurable
— High current drive on any GPIO pin: 50 mA/pin
current sink
— Each GPIO pin supports high-impedance inputs,
internal pull-ups, open drain outputs or traditional
CMOS outputs
— Maskable interrupts on all I/O pins
• SPI serial communication block
— Master or slave operation
— 2 Mbit/s transfers
• Four 8-bit Input Capture registers
— Two registers each for two input pins
— Capture timer setting with five prescaler settings
— Separate registers for rising and falling edge capture
— Simplifies interface to RF inputs for wireless
applications
• Internal low-power wake-up timer during suspend
mode
— Periodic wake-up with no external components
• Optional 6-MHz internal oscillator mode
— Allows fast start-up from suspend mode
• Watchdog Reset (WDR)
• Low-voltage Reset at 3.75V
• Internal brown-out reset for suspend mode
• Improved output drivers to reduce EMI
• Operating voltage from 4.0V to 5.5VDC
• Operating temperature from 0°C to 70°C
• CY7C63723C available in 18-pin SOIC, 18-pin PDIP
• CY7C63743C available in 24-pin SOIC, 24-pin PDIP,
Document #: 38-08022 Rev. *C Revised February 25, 2006
2.0 Logic Block Diagram
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XTALOUT XTALIN/P2.1
Internal
Oscillator
EPROM
8K Byte
Brown-out
Reset
Xtal
Oscillator
8-bit
RISC
Core
Wake-Up
Timer
Interrupt
Controller
Watch
Dog
Timer
Low
Voltage
Reset
3.3V
Regulator
VREG/P2.0
3.0 Functional Overview
3.1enCoRe USB—The New USB Standard
Cypress has reinvented its leadership position in the
low-speed USB market with a new family of innovative
microcontrollers. Introducing...enCoRe USB—“enhanced
Component Reduction.” Cypress has leveraged its design
expertise in USB solutions to create a new family of low-speed
USB microcontrollers that enables peripheral developers to
design new products with a minimum number of components.
At the heart of the enCoRe USB technology is the breakthrough design of a crystalless oscillator. By integrating the
oscillator into our chip, an external crystal or resonator is no
longer needed. We have also integrated other external components commonly found in low-speed USB applications such as
pull-up resistors, wake-up circuitry, and a 3.3V regulator. All of
this adds up to a lower system cost.
The CY7C637xxC is an 8-bit RISC one-time-programmable
(OTP) microcontroller. The instruction set has been optimized
specifically for USB and PS/2 operations, although the microcontrollers can be used for a variety of other embedded applications.
The CY7C637xxC features up to 16 GPIO pins to support
USB, PS/2 and other applications. The I/O pins are grouped
into two ports (Port 0 to 1) where each pin can be individually
configured as inputs with internal pull-ups, open drain outputs,
or traditional CMOS outputs with programmable drive strength
of up to 50 mA output drive. Additionally, each I/O pin can be
used to generate a GPIO interrupt to the microcontroller. Note
the GPIO interrupts all share the same “GPIO” interrupt vector.
The CY7C637xxC microcontrollers feature an internal oscillator. With the presence of USB traffic, the internal oscillator
can be set to precisely tune to USB timing requirements (6
RAM
256 Byte
USB
Engine
12-bit
Timer
Port 1
GPIO
Capture
Timers
Port 0
GPIO
SPI
USB &
PS/2
Xcvr
D+,D–
MHz ±1.5%). Optionally, an external 6-MHz ceramic resonator
can be used to provide a higher precision reference for USB
operation. This clock generator reduces the clock-related
noise emissions (EMI). The clock generator provides the 6and 12-MHz clocks that remain internal to the microcontroller.
The CY7C637xxC has 8 Kbytes of EPROM and 256 bytes of
data RAM for stack space, user variables, and USB FIFOs.
These parts include low-voltage reset logic, a Watchdog timer,
a vectored interrupt controller, a 12-bit free-running timer, and
capture timers. The low-voltage reset (LVR) logic detects
when power is applied to the device, resets the logic to a
known state, and begins executing instructions at EPROM
address 0x0000. LVR will also reset the part when V
below the operating voltage range. The Watchdog timer can
be used to ensure the firmware never gets stalled for more
than approximately 8 ms.
The microcontroller supports 10 maskable interrupts in the
vectored interrupt controller. Interrupt sources include the USB
Bus-Reset, the 128-µs and 1.024-ms outputs from the
free-running timer, three USB endpoints, two capture timers,
an internal wake-up timer and the GPIO ports. The timers bits
cause periodic interrupts when enabled. The USB endpoints
interrupt after USB transactions complete on the bus. The
capture timers interrupt whenever a new timer value is saved
due to a selected GPIO edge event. The GPIO ports have a
level of masking to select which GPIO inputs can cause a
GPIO interrupt. For additional flexibility, the input transition
polarity that causes an interrupt is programmable for each
GPIO pin. The interrupt polarity can be either rising or falling
edge.
The free-running 12-bit timer clocked at 1 MHz provides two
interrupt sources as noted above (128 µs and 1.024 ms). The
timer can be used to measure the duration of an event under
firmware control by reading the timer at the start and end of an
P1.0–P1.7
P0.0–P0.7
CC
drops
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event, and subtracting the two values. The four capture timers
save a programmable 8 bit range of the free-running timer
when a GPIO edge occurs on the two capture pins (P0.0,
P0.1).
The CY7C637xxC includes an integrated USB serial interface
engine (SIE) that supports the integrated peripherals. The
hardware supports one USB device address with three
endpoints. The SIE allows the USB host to communicate with
the function integrated into the microcontroller. A 3.3V
The USB D+ and D– USB pins can alternately be used as PS/2
SCLK and SDATA signals, so that products can be designed
to respond to either USB or PS/2 modes of operation. PS/2
operation is supported with internal pull-up resistors on SCLK
and SDATA, the ability to disable the regulator output pin, and
an interrupt to signal the start of PS/2 activity. No external
components are necessary for dual USB and PS/2 systems,
and no GPIO pins need to be dedicated to switching between
modes. Slow edge rates operate in both modes to reduce EMI.
regulated output pin provides a pull-up source for the external
USB resistor on the D– pin.
4.0 Pin Configurations
Top View
CY7C63723C
18-pin SOIC/PDIP
P0.0
1
P0.1
2
P0.2
3
P0.3
4
P1.0
5
6
VSS
7
VPP
VREG/P2.0
XTALIN/P2.1
8
9
18
17
16
15
14
13
12
11
10
P0.4
P0.5
P0.6
P0.7
P1.1
D+/SCLK
D–/SDATA
VCC
XTALOUT
CY7C63743C
24-pin SOIC/PDIP/QSOP
P0.0
1
P0.1
P0.2
P0.3
P1.0
P1.2
P1.4
P1.6
VSS
VPP
VREG/P2.0
XTALIN/P2.1
24
23
2
22
3
21
4
20
5
19
6
18
7
17
8
16
9
15
10
14
11
13
12
P0.4
P0.5
P0.6
P0.7
P1.1
P1.3
P1.5
P1.7
D+/SCLK
D–/SDATA
VCC
XTALOUT
CY7C63722C-XC
DIE
1 P0.0
3 P0.2
2 P0.1
P0.3
P1.0
P1.2
P1.4
P1.6
VSS
VSS
25 P0.4
4
5
6
7
8
9
10
111213
VPP
VREG
XTALIN/P2.1
24 P0.5
23 P0.6
22
P0.7
21
P1.1
20
P1.3
19
P1.5
18
P1.7
17
D+/SCLK
15
16
14
VCC
D-/SDATA
XTALOUT
5.0 Pin Definitions
CY7C63723C CY7C63743C CY7C63722C
NameI/O
D–/SDATA,
D+/SCLK
P0[7:0]I/O1, 2, 3, 4,
I/O12
13
15, 16, 17, 18
15
16
1, 2, 3, 4,
21, 22, 23, 24
16
17
1, 2, 3, 4,
22, 23, 24, 25
USB differential data lines (D– and D+), or PS/2 clock
and data signals (SDATA and SCLK)
GPIO Port 0 capable of sinking up to 50 mA/pin, or
sinking controlled low or high programmable current.
Can also source 2 mA current, provide a resistive
pull-up, or serve as a high-impedance input. P0.0 and
P0.1 provide inputs to Capture Timers A and B, respectively.
P1[7:0]I/O5, 145, 6, 7, 8,
17, 18, 19, 20
5, 6, 7, 8,
18, 19, 20, 21
IO Port 1 capable of sinking up to 50 mA/pin, or sinking
controlled low or high programmable current. Can also
source 2 mA current, provide a resistive pull-up, or
serve as a high-impedance input.
XTALIN/P2.1IN912136-MHz ceramic resonator or external clock input, or
P2.1 input
XTALOUTOUT1013146-MHz ceramic resonator return pin or internal oscillator
output
V
PP
V
CC
71011Programming voltage supply, ground for normal
operation
111415Voltage supply
VREG/P2.0 81112Voltage supply for 1.3-kΩ USB pull-up resistor (3.3V
nominal). Also serves as P2.0 input.
V
SS
699, 10Ground
Description18-Pin24-Pin25-Pad
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6.0 Programming Model
Refer to the CYASM Assembler User’s Guide for more details
on firmware operation with the CY7C637xxC microcontrollers.
6.1Program Counter (PC)
The 14-bit program counter (PC) allows access for up to 8
Kbytes of EPROM using the CY7C637xxC architecture. The
program counter is cleared during reset, such that the first
instruction executed after a reset is at address 0x0000. This
instruction is typically a jump instruction to a reset handler that
initializes the application.
The lower 8 bits of the program counter are incremented as
instructions are loaded and executed. The upper six bits of the
program counter are incremented by executing an XPAGE
instruction. As a result, the last instruction executed within a
256-byte “page” of sequential code should be an XPAGE
instruction. The assembler directive “XPAGEON” will cause
the assembler to insert XPAGE instructions automatically. As
instructions can be either one or two bytes long, the assembler
may occasionally need to insert a NOP followed by an XPAGE
for correct execution.
The program counter of the next instruction to be executed,
carry flag, and zero flag are saved as two bytes on the program
stack during an interrupt acknowledge or a CALL instruction.
The program counter, carry flag, and zero flag are restored
from the program stack only during a RETI instruction.
Please note the program counter cannot be accessed directly
by the firmware. The program stack can be examined by
reading SRAM from location 0x00 and up.
6.28-bit Accumulator (A)
The accumulator is the general-purpose, do everything
register in the architecture where results are usually calculated.
6.38-bit Index Register (X)
The index register “X” is available to the firmware as an
auxiliary accumulator. The X register also allows the processor
to perform indexed operations by loading an index value
into X.
The return from interrupt (RETI) instruction decrements the
program stack pointer, then restores the second byte from
memory addressed by the PSP. The program stack pointer is
decremented again and the first byte is restored from memory
addressed by the PSP. After the program counter and flags
have been restored from stack, the interrupts are enabled. The
effect is to restore the program counter and flags from the
program stack, decrement the program stack pointer by two,
and reenable interrupts.
The call subroutine (CALL) instruction stores the program
counter and flags on the program stack and increments the
PSP by two.
The return from subroutine (RET) instruction restores the
program counter, but not the flags, from program stack and
decrements the PSP by two.
Note that there are restrictions in using the JMP, CALL, and
INDEX instructions across the 4-KByte boundary of the
program memory. Refer to the CYASM Assembler User’sGuide for a detailed description.
6.58-bit Data Stack Pointer (DSP)
The data stack pointer (DSP) supports PUSH and POP
instructions that use the data stack for temporary storage. A
PUSH instruction will pre-decrement the DSP, then write data
to the memory location addressed by the DSP. A POP
instruction will read data from the memory location addressed
by the DSP, then post-increment the DSP.
During a reset, the Data Stack Pointer will be set to zero. A
PUSH instruction when DSP equals zero will write data at the
top of the data RAM (address 0xFF). This would write data to
the memory area reserved for a FIFO for USB endpoint 0. In
non-USB applications, this works fine and is not a problem.
For USB applications, the firmware should set the DSP to an
appropriate location to avoid a memory conflict with RAM
dedicated to USB FIFOs. The memory requirements for the
USB endpoints are shown in Section 8.2. For example,
assembly instructions to set the DSP to 20h (giving 32 bytes
for program and data stack combined) are shown below.
MOV A,20h; Move 20 hex into Accumulator (must be
D8h or less to avoid USB FIFOs)
SWAP A,DSP ; swap accumulator value into DSP register
6.48-bit Program Stack Pointer (PSP)
During a reset, the program stack pointer (PSP) is set to zero.
This means the program “stack” starts at RAM address 0x00
and “grows” upward from there. Note that the program stack
pointer is directly addressable under firmware control, using
the MOV PSP,A instruction. The PSP supports interrupt
service under hardware control and CALL, RET, and RETI
instructions under firmware control.
During an interrupt acknowledge, interrupts are disabled and
the program counter, carry flag, and zero flag are written as
two bytes of data memory. The first byte is stored in the
memory addressed by the program stack pointer, then the
PSP is incremented. The second byte is stored in memory
addressed by the program stack pointer and the PSP is incremented again. The net effect is to store the program counter
and flags on the program “stack” and increment the program
stack pointer by two.
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6.6Address Modes
The CY7C637xxC microcontrollers support three addressing
modes for instructions that require data operands: data, direct,
and indexed.
6.6.1Data
The “Data” address mode refers to a data operand that is
actually a constant encoded in the instruction. As an example,
consider the instruction that loads A with the constant 0x30:
• MOV A, 30h
This instruction will require two bytes of code where the first
byte identifies the “MOV A” instruction with a data operand as
the second byte. The second byte of the instruction will be the
constant “0xE8h”. A constant may be referred to by name if a
prior “EQU” statement assigns the constant value to the name.
For example, the following code is equivalent to the example
shown above.
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• DSPINIT: EQU 30h
• MOV A,DSPINIT
6.6.2Direct
“Direct” address mode is used when the data operand is a
variable stored in SRAM. In that case, the one byte address of
the variable is encoded in the instruction. As an example,
consider an instruction that loads A with the contents of
memory address location 0x10h:
• MOV A, [10h]
In normal usage, variable names are assigned to variable
addresses using “EQU” statements to improve the readability
of the assembler source code. As an example, the following
code is equivalent to the example shown above.
• buttons: EQU 10h
• MOV A, [buttons]
6.6.3Indexed
“Indexed” address mode allows the firmware to manipulate
arrays of data stored in SRAM. The address of the data
operand is the sum of a constant encoded in the instruction
and the contents of the “X” register. In normal usage, the
constant will be the “base” address of an array of data and the
X register will contain an index that indicates which element of
the array is actually addressed.
• array: EQU 10h
•MOV X,3
• MOV A, [x+array]
This would have the effect of loading A with the fourth element
of the SRAM “array” that begins at address 0x10h. The fourth
element would be at address 0x13h.
7.0 Instruction Set Summary
Refer to the CYASM Assembler User’s Guide for detailed
information on these instructions. Note that conditional jump
instructions (i.e., JC, JNC, JZ, JNZ) take five cycles if jump is
taken, four cycles if no jump.
14 -bit PC0x0000Program execution begins here after a reset
[1]
0x0002USB Bus Reset interrupt vector
0x0004128-µs timer interrupt vector
0x00061.024-ms timer interrupt vector
0x0008USB endpoint 0 interrupt vector
0x000AUSB endpoint 1 interrupt vector
0x000CUSB endpoint 2 interrupt vector
0x000ESPI interrupt vector
0x0010Capture timer A interrupt Vector
0x0012Capture timer B interrupt vector
0x0014GPIO interrupt vector
0x0016Wake-up interrupt vector
0x0018Program Memory begins here
0x1FDF8 KB PROM ends here (8K - 32 bytes). See Note below
Figure 8-1. Program Memory Space with Interrupt Vector Table
Note:
1. The upper 32 bytes of the 8K PROM are reserved. Therefore, the user’s program must not overwrite this space.
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8.2Data Memory Organization
The CY7C637xxC microcontrollers provide 256 bytes of data
RAM. In normal usage, the SRAM is partitioned into four
areas: program stack, data stack, user variables and USB
endpoint FIFOs as shown below.
After resetAddress
8-bit DSP8-bit PSP0x00Program Stack Growth
(User’s firmware moves DSP)
8-bit DSPUser SelectedData Stack Growth
User Variables
0xE8
USB FIFO for Address A endpoint 2
CY7C63722C
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CY7C63743C
0xF0
USB FIFO for Address A endpoint 1
0xF8
USB FIFO for Address A endpoint 0
Top of RAM Memory0xFF
Figure 8-2. Data Memory Organization
8.3I/O Register Summary
I/O registers are accessed via the I/O Read (IORD) and I/O
Write (IOWR, IOWX) instructions. IORD reads the selected
port into the accumulator. IOWR writes data from the accumulator to the selected port. Indexed I/O Write (IOWX) adds the
contents of X to the address in the instruction to form the port
address and writes data from the accumulator to the specified
Table 8-1. I/O Register Summary
Register NameI/O AddressRead/WriteFunctionFig.
Port 0 Data0x00R/WGPIO Port 012-2
Port 1 Data0x01R/WGPIO Port 112-3
Port 2 Data0x02RAuxiliary input register for D+, D–, VREG, XTALIN 12-8
Port 0 Interrupt Enable0x04WInterrupt enable for pins in Port 021-4
Port 1 Interrupt Enable0x05WInterrupt enable for pins in Port 121-5
Port 0 Interrupt Polarity 0x06WInterrupt polarity for pins in Port 021-6
Port 1 Interrupt Polarity 0x07WInterrupt polarity for pins in Port 121-7
Port 0 Mode0 0x0AWControls output configuration for Port 012-4
Port 0 Mode10x0BW12-5
Port 1 Mode00x0CWControls output configuration for Port 112-6
Port 1 Mode10x0DW12-7
port. Note that specifying address 0 with IOWX (e.g., IOWX
0h) means the I/O port is selected solely by the contents of X.
Note: All bits of all registers are cleared to all zeros on
reset, except the Processor Status and Control Register
(Figure 20-1). All registers not listed are reserved, and should
never be written by firmware. All bits marked as reserved
should always be written as 0 and be treated as undefined by
reads.
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Table 8-1. I/O Register Summary (continued)
Register NameI/O AddressRead/WriteFunctionFig.
USB Device Address0x10R/WUSB Device Address register14-1
Processor Status & Control0xFFR/WProcessor status and control20-1
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9.0 Clocking
The chip can be clocked from either the internal on-chip clock,
or from an oscillator based on an external resonator/crystal, as
shown in Figure 9-1. No additional capacitance is included on
chip at the XTALIN/OUT pins. Operation is controlled by the
Clock Configuration Register, Figure 9-2.
External Clock Resume Delay bit selects the delay time
when switching to the external oscillator from the internal
oscillator mode, or when waking from suspend mode with
the external oscillator enabled.
1 = 4 ms delay.
0 = 128 µs delay.
The delay gives the oscillator time to start up. The shorter
time is adequate for operation with ceramic resonators,
while the longer time is preferred for start-up with a crystal.
(These times do not include an initial oscillator start-up
time which depends on the resonating element. This time
Bit [6:4]: Wake-up Timer Adjust Bit [2:0]
The Wake-up Timer Adjust Bits are used to adjust the
Wake-up timer period.
If the Wake-up interrupt is enabled in the Global Interrupt
Enable Register, the microcontroller will generate wake-up
interrupts periodically. The frequency of these periodical
wake-up interrupts is adjusted by setting the Wake-up Timer Adjust Bit [2:0], as described in Section 11.2. One common use of the wake-up interrupts is to generate periodical
wake-up events during suspend mode to check for changes, such as looking for movement in a mouse, while maintaining a low average power.
is typically 50–100 µs for ceramic resonators and 1–10 ms
for crystals). Note that this bit only selects the delay time for
the external clock mode. When waking from suspend mode
with the internal oscillator (Bit 0 is LOW), the delay time is
only 8 µs in addition to a delay of approximately 1 µs for the
oscillator to start.
Bit 3: Low-voltage Reset Disable
When V
ue of V
the microcontroller enters a partial suspend state for a period of t
Program execution begins from address 0x0000 after this
t
START
drops below V
CC
) and the Low-voltage Reset circuit is enabled,
LVR
(see Section 26.0 for the value of t
START
(see Section 25.0 for the val-
LVR
delay period. This provides time for VCC to stabilize
START
).
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before the part executes code. See Section 10.1 for more
details.
1 = Disables the LVR circuit.
0 = Enables the LVR circuit.
Bit 2: Precision USB Clocking Enable
The Precision USB Clocking Enable only affects operation
in internal oscillator mode. In that mode, this bit must be
set to 1 to cause the internal clock to automatically precisely tune to USB timing requirements (6 MHz ±1.5%).
The frequency may have a looser initial tolerance at power-up, but all USB transmissions from the chip will meet the
USB specification.
1 = Enabled. The internal clock accuracy is 6 MHz ±1.5%
after USB traffic is received.
0 = Disabled. The internal clock accuracy is 6 MHz ±5%.
Bit 1: Internal Clock Output Disable
The Internal Clock Output Disable is used to keep the internal clock from driving out to the XTALOUT pin. This bit has
no effect in the external oscillator mode.
0 = Enable the internal clock output. The internal clock is
driven out to the XTALOUT pin.
Bit 0: External Oscillator Enable
At power-up, the chip operates from the internal clock by
default. Setting the External Oscillator Enable bit HIGH disables the internal clock, and halts the part while the external
resonator/crystal oscillator is started. Clearing this bit has
no immediate effect, although the state of this bit is used
when waking out of suspend mode to select between internal and external clock. In internal clock mode, XTALIN pin
will be configured as an input with a weak pull-down and
can be used as a GPIO input (P2.1).
1 = Enable the external oscillator. The clock is switched to
external clock mode, as described in Section 9.1.
0 = Enable the internal oscillator.
9.1Internal/External Oscillator Operation
The internal oscillator provides an operating clock, factory set
to a nominal frequency of 6 MHz. This clock requires no
external components. At power-up, the chip operates from the
internal clock. In this mode, the internal clock is buffered and
driven to the XTALOUT pin by default, and the state of the
XTALIN pin can be read at Port 2.1. While the internal clock is
enabled, its output can be disabled at the XTALOUT pin by
setting the Internal Clock Output Disable bit of the Clock
Configuration Register.
Setting the External Oscillator Enable bit of the Clock Configuration Register HIGH disables the internal clock, and halts
the part while the external resonator/crystal oscillator is
started. The steps involved in switching from Internal to
External Clock mode are as follows:
1. At reset, chip begins operation using the internal clock.
2. Firmware sets Bit 0 of the Clock Configuration Register. For
example,
mov A, 1h ; Set Bit 0 HIGH (External Oscil-
lator Enable bit). Bit 7 cleared
gives faster start-up
iowr F8h; Write to Clock Configuration
Register
3. Internal clocking is halted, the internal oscillator is disabled,
and the external clock oscillator is enabled.
4. After the external clock becomes stable, chip clocks are
re-enabled using the external clock signal. (Note that the
time for the external clock to become stable depends on the
external resonating device; see next section.)
5. After an additional delay the CPU is released to run. This
delay depends on the state of the Ext. Clock Resume Delay
bit of the Clock Configuration Register. The time is 128 µs
if the bit is 0, or 4 ms if the bit is 1.
6. Once the chip has been set to external oscillator, it can only
return to internal clock when waking from suspend mode.
Clearing bit 0 of the Clock Configuration Register will not
re-enable internal clock mode until suspend mode is
entered. See Section 11.0 for more details on suspend
mode operation.
If the Internal Clock is enabled, the XTALIN pin can serve as
a general purpose input, and its state can be read at Port 2,
Bit 1 (P2.1). Refer to Figure 12-8 for the Port 2 Data Register.
In this mode, there is a weak pull-down at the XTALIN pin. This
input cannot provide an interrupt source to the CPU.
9.2External Oscillator
The user can connect a low-cost ceramic resonator or an
external oscillator to the XTALIN/XTALOUT pins to provide a
precise reference frequency for the chip clock, as shown in
Figure 9-1. The external components required are a ceramic
resonator or crystal and any associated capacitors. To run
from the external resonator, the External Oscillator Enable bit
of the Clock Configuration Register must be set to 1, as
explained in the previous section.
Start-up times for the external oscillator depend on the
resonating device. Ceramic resonator based oscillators
typically start in less than 100 µs, while crystal based oscillators take longer, typically 1 to 10 ms. Board capacitance
should be minimized on the XTALIN and XTALOUT pins by
keeping the traces as short as possible.
An external 6-MHz clock can be applied to the XTALIN pin if
the XTALOUT pin is left open.
10.0 Reset
The USB Controller supports three types of resets. The effects
of the reset are listed below. The reset types are:
1. Low-voltage Reset (LVR)
2. Brown Out Reset (BOR)
3. Watchdog Reset (WDR)
The occurrence of a reset is recorded in the Processor Status
and Control Register (Figure 20-1). Bits 4 (Low-voltage or
Brown-out Reset bit) and 6 (Watchdog Reset bit) are used to
record the occurrence of LVR/BOR and WDR respectively.
The firmware can interrogate these bits to determine the cause
of a reset.
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The microcontroller begins execution from ROM address
0x0000 after a LVR, BOR, or WDR reset. Although this looks
like interrupt vector 0, there is an important difference. Reset
processing does NOT push the program counter, carry flag,
and zero flag onto program stack. Attempting to execute either
a RET or RETI in the reset handler will cause unpredictable
execution results.
The following events take place on reset. More details on the
various resets are given in the following sections.
1. All registers are reset to their default states (all bits cleared,
except in Processor Status and Control Register).
2. GPIO and USB pins are set to high-impedance state.
3. The VREG pin is set to high-impedance state.
4. Interrupts are disabled.
5. USB operation is disabled and must be enabled by firmware
if desired, as explained in Section 14.1.
6. For a BOR or LVR, the external oscillator is disabled and
Internal Clock mode is activated, followed by a time-out
period t
the clock mode, and there is no delay for V
on a WDR. Note that the External Oscillator Enable (Bit 0,
for VCC to stabilize. A WDR does not change
START
CC
stabilization
Figure 9-2) will be cleared by a WDR, but it does not take
effect until suspend mode is entered.
7. The Program Stack Pointer (PSP) and Data Stack Pointer
(DSP) reset to address 0x00. Firmware should move the
DSP for USB applications, as explained in Section 6.5.
8. Program execution begins at address 0x0000 after the
appropriate time-out period.
10.1Low-voltage Reset (LVR)
When V
started and the Low-voltage Reset is initially enabled by
default. At the point where V
Section 25.0 for the value of V
counting for a period of t
of t
START
a partial suspend state to wait for V
begins executing code from address 0x0000.
As long as the LVR circuit is enabled, this reset sequence
repeats whenever the V
LVR can be disabled by firmware by setting the Low-voltage
is first applied to the chip, the internal oscillator is
CC
has risen above V
). During this t
CC
), an internal counter starts
LVR
(see Section 26.0 for the value
START
time, the microcontroller enters
START
pin voltage drops below V
CC
to stabilize before it
CC
LVR
LVR
(see
. The
Reset Disable bit in the Clock Configuration Register
(Figure 9-2). In addition, the LVR is automatically disabled in
suspend mode to save power. If the LVR was enabled before
entering suspend mode, it becomes active again once the
suspend mode ends.
When LVR is disabled during normal operation (i.e., by writing
‘0’ to the Low-voltage Reset Disable bit in the Clock Configuration Register), the chip may enter an unknown state if V
drops below V
times during normal operation. If LVR is disabled (i.e., by
. Therefore, LVR should be enabled at all
LVR
CC
firmware or during suspend mode), a secondary low-voltage
monitor, BOR, becomes active, as described in the next
section. The LVR/BOR Reset bit of the Processor Status and
Control Register (Figure 20-1), is set to ‘1’ if either a LVR or
BOR has occurred.
10.2Brown Out Reset (BOR)
The Brown Out Reset (BOR) circuit is always active and
behaves like the POR. BOR is asserted whenever the V
voltage to the device is below an internally defined trip voltage
CC
of approximately 2.5V. The BOR re-enables LVR. That is, once
V
drops and trips BOR, the part remains in reset until V
CC
rises above V
normal operation resumes, and the microcontroller starts
executing code from address 0x00 after the t
. At that point, the t
LVR
delay occurs before
START
START
delay.
CC
In suspend mode, only the BOR detection is active, giving a
reset if V
is suspended and code is not executing, this lower reset
drops below approximately 2.5V. Since the device
CC
voltage is safe for retaining the state of all registers and
memory. Note that in suspend mode, LVR is disabled as
discussed in Section 10.1.
10.3Watchdog Reset (WDR)
The Watchdog Timer Reset (WDR) occurs when the internal
Watchdog timer rolls over. Writing any value to the write-only
Watchdog Reset Register at address 0x26 will clear the timer.
The timer will roll over and WDR will occur if it is not cleared
within t
(Watchdog Reset bit) of the Processor Status and Control
Register is set to record this event (see Section 20.0 for more
details). A Watchdog Timer Reset typically lasts for 2–4 ms,
after which the microcontroller begins execution at ROM
address 0x0000.
(see Figure 10-1) of the last clear. Bit 6
WATCH
t
WATCH = 10.1 to
14.6 ms
WDR
(at F
OSC
= 6 MHz)
2–4 ms
At least 10.1 ms
since last write to WDR
WDR goes HIGH
for 2–4 ms
Execution begins at
ROM Address 0x0000
Figure 10-1. Watchdog Reset (WDR, Address 0x26)
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11.0 Suspend Mode
The CY7C637xxC parts support a versatile low-power
suspend mode. In suspend mode, only an enabled interrupt or
a LOW state on the D–/SDATA pin will wake the part. Two
options are available. For lowest power, all internal circuits can
be disabled, so only an external event will resume operation.
Alternatively, a low-power internal wake-up timer can be used
to trigger the wake-up interrupt. This timer is described in
Section 11.2, and can be used to periodically poll the system
to check for changes, such as looking for movement in a
mouse, while maintaining a low average power.
The CY7C637xxC is placed into a low-power state by setting
the Suspend bit of the Processor Status and Control Register
(Figure 20-1). All logic blocks in the device are turned off
except the GPIO interrupt logic, the D–/SDATA pin input
receiver, and (optionally) the wake-up timer. The clock oscillators, as well as the free-running and Watchdog timers are
shut down. Only the occurrence of an enabled GPIO interrupt,
wake-up interrupt, SPI slave interrupt, or a LOW state on the
D–/SDATA pin will wake the part from suspend (D– LOW
indicates non-idle USB activity). Once one of these resuming
conditions occurs, clocks will be restarted and the device
returns to full operation after the oscillator is stable and the
selected delay period expires. This delay period is determined
by selection of internal vs. external clock, and by the state of
the Ext. Clock Resume Delay as explained in Section 9.0.
In suspend mode, any enabled and pending interrupt will wake
the part up. The state of the Interrupt Enable Sense bit (Bit 2,
Figure 20-1) does not have any effect. As a result, any interrupts not intended for waking from suspend should be disabled
through the Global Interrupt Enable Register and the USB End
Point Interrupt Enable Register (Section 21.0).
If a resuming condition exists when the suspend bit is set, the
part will still go into suspend and then awake after the appropriate delay time. The Run bit in the Processor Status and
Control Register must be set for the part to resume out of
suspend.
Once the clock is stable and the delay time has expired, the
microcontroller will execute the instruction following the I/O
write that placed the device into suspend mode before
servicing any interrupt requests.
To achieve the lowest possible current during suspend mode,
all I/O should be held at either V
GPIO bit interrupts (Figure 21-4 and Figure 21-5) should be
disabled for any pins that are not being used for a wake-up
interrupt. This should be done even if the main GPIO Interrupt
Enable (Figure 21-1) is off.
Typical code for entering suspend is shown below:
...; All GPIO set to low-power state (no floating
pins, and bit interrupts disabled unless
using for wake-up)
...; Enable GPIO and/or wake-up timer
interrupts if desired for wake-up
...; Select clock mode for wake-up (see
Section 11.1)
mov a, 09h; Set suspend and run bits
iowr FFh; Write to Status and Control Register –
Enter suspend, wait for GPIO/wake-up
interrupt or USB activity
nop; This executes before any ISR
...; Remaining code for exiting suspend
routine
or ground. In addition, the
CC
11.1Clocking Mode on Wake-up from Suspend
When exiting suspend on a wake-up event, the device can be
configured to run in either Internal or External Clock mode.
The mode is selected by the state of the External Oscillator
Enable bit in the Clock Configuration Register (Figure 9-2).
Using the Internal Clock saves the external oscillator start-up
time and keeps that oscillator off for additional power savings.
The external oscillator mode can be activated when desired,
similar to operation at power-up.
The sequence of events for these modes is as follows:
Wake in Internal Clock Mode:
1. Before entering suspend, clear bit 0 of the Clock Configuration Register. This selects Internal clock mode after suspend.
2. Enter suspend mode by setting the suspend bit of the
Processor Status and Control Register.
3. After a wake-up event, the internal clock starts immediately
(within 2 µs).
4. A time-out period of 8 µs passes, and then firmware
execution begins.
5. At some later point, to activate External Clock mode, set bit
0 of the Clock Configuration Register. This halts the internal
clocks while the external clock becomes stable. After an
additional time-out (128 µs or 4 ms, see Section 9.0),
firmware execution resumes.
Wake in External Clock Mode:
1. Before entering suspend, the external clock must be selected by setting bit 0 of the Clock Configuration Register. Make
sure this bit is still set when suspend mode is entered. This
selects External clock mode after suspend.
2. Enter suspend mode by setting the suspend bit of the
Processor Status and Control Register.
3. After a wake-up event, the external oscillator is started. The
clock is monitored for stability (this takes approximately
50–100 µs with a ceramic resonator).
4. After an additional time-out period (128 µs or 4 ms, see
Section 9.0), firmware execution resumes.
11.2Wake-up Timer
The wake-up timer runs whenever the wake-up interrupt is
enabled, and is turned off whenever that interrupt is disabled.
Operation is independent of whether the device is in suspend
mode or if the global interrupt bit is enabled. Only the Wake-up
Timer Interrupt Enable bit (Figure 21-1) controls the wake-up
timer.
Once this timer is activated, it will give interrupts after its
time-out period (see below). These interrupts continue periodically until the interrupt is disabled. Whenever the interrupt is
disabled, the wake-up timer is reset, so that a subsequent
enable always results in a full wake-up time.
The wake-up timer can be adjusted by the user through the
Wake-up Timer Adjust bits in the Clock Configuration Register
(Figure 9-2). These bits clear on reset. In addition to allowing
the user to select a range for the wake-up time, a firmware
algorithm can be used to tune out initial process and operating
condition variations in this wake-up time. This can be done by
timing the wake-up interrupt time with the accurate 1.024-ms
timer interrupt, and adjusting the Timer Adjust bits accordingly
to approximate the desired wake-up time.
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Table 11-1. Wake-up Timer Adjust Settings
Adjust Bits [2:0]
(Bits [6:4] in Figure 9-2)Wake-up Time
000 (reset state)1 * t
0012 * t
0104 * t
0118 * t
10016 * t
10132 * t
1106 4 * t
111128 * t
See Section 26.0 for the value of t
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
12.0 General Purpose I/O Ports
Ports 0 and 1 provide up to 16 versatile GPIO pins that can be
read or written (the number of pins depends on package type).
Figure 12-1 shows a diagram of a GPIO port pin.
CY7C63722C
CY7C63723C
CY7C63743C
2
(Data Reg must be 1
for SPI outputs)
Port Read
Interrupt
Logic
SPI Bypass (P0.5–P0.7 only)
(=1 if SPI inactive, or for non-SPI pins)
Internal
Data Bus
GPIO
Mode
Data
Out
Register
Port Write
Interrupt
Polarity
Interrupt
Enable
Figure 12-1. Block Diagram of GPIO Port (one pin shown)
Port 0 is an 8-bit port; Port 1 contains either 2 bits, P1.1–P1.0
in the CY7C63723C, or all 8 bits, P1.7–P1.0 in the
CY7C63743C parts. Each bit can also be selected as an
interrupt source for the microcontroller, as explained in Section
21.0.
The data for each GPIO pin is accessible through the Port
Data register. Writes to the Port Data register store outgoing
data state for the port pins, while reads from the Port Data
register return the actual logic value on the port pins, not the
Port Data register contents.
V
CC
Q1
Control
14 kΩ
Q3
GPIO
Pin
Q2
Threshold Select
To Capture Timers (P0.0, P0.1)
and SPI (P0.4–P0.7))
To Interrupt
Controller
Each GPIO pin is configured independently. The driving state
of each GPIO pin is determined by the value written to the pin’s
Data Register and by two associated pin’s Mode0 and Mode1
bits.
The Port 0 Data Register is shown in Figure 12-2, and the Port
1 Data Register is shown in Figure 12-3. The Mode0 and
Mode1 bits for the two GPIO ports are given in Figure 12-4
through Figure 12-7.
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Bit #76543210
Bit NameP0
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Reset00000000
Figure 12-2. Port 0 Data (Address 0x00)
Bit [7:0]: P0[7:0]
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
Bit #76543210
Bit NameP1
NotesPins 7:2 only in CY7C63743CPins 1:0 in
all parts
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Reset00000000
Figure 12-3. Port 1 Data (Address 0x01)
Bit [7:0]: P1[7:0]
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
Bit #76543210
Bit NameP0[7:0] Mode0
Read/WriteWWWWWWWW
Reset00000000
Figure 12-4. GPIO Port 0 Mode0 Register (Address 0x0A)
Bit [7:0]: P0[7:0] Mode 0
1 = Port 0 Mode 0 is logic HIGH
0 = Port 0 Mode 0 is logic LOW
Bit #76543210
Bit NameP0[7:0] Mode1
Read/WriteWWWWWWWW
Reset00000000
Figure 12-5. GPIO Port 0 Mode1 Register (Address 0x0B)
Bit [7:0]: P0[7:0] Mode 1
1 = Port Pin Mode 1 is logic HIGH
0 = Port Pin Mode 1 is logic LOW
Bit # 76543210
Bit NameP1[7:0] Mode0
Read/WriteWWWWWWWW
Reset00000000
Figure 12-6. GPIO Port 1 Mode0 Register (Address 0x0C)
Bit [7:0]: P1[7:0] Mode 0
1 = Port Pin Mode 0 is logic HIGH
0 = Port Pin Mode 0 is logic LOW
Bit # 76543210
Bit NameP1[7:0] Mode1
Read/WriteWWWWWWWW
Reset00000000
Figure 12-7. GPIO Port 1 Mode1 Register (Address 0x0D)
Bit [7:0]: P1[7:0] Mode 1
1 = Port Pin Mode 1 is logic HIGH
0 = Port Pin Mode 1 is logic LOW
Each pin can be independently configured as high-impedance
inputs, inputs with internal pull-ups, open drain outputs, or
traditional CMOS outputs with selectable drive strengths.
The driving state of each GPIO pin is determined by the value
written to the pin’s Data Register and by its associated Mode0
and Mode1 bits. Table 12-1 lists the configuration states
based on these bits. The GPIO ports default on reset to all
Data and Mode Registers cleared, so the pins are all in a
high-impedance state. The available GPIO output drive
strength are:
• Hi-Z Mode (Mode1 = 0 and Mode0 = 0)
Q1, Q2, and Q3 (Figure 12-1) are OFF. The GPIO pin is not
driven internally. Performing a read from the Port Data Register return the actual logic value on the port pins.
• Low Sink Mode (Mode1 = 1, Mode0 = 0, and the pin’s Data
Register = 0)
Q1 and Q3 are OFF. Q2 is ON. The GPIO pin is capable of
sinking 2 mA of current.
• Medium Sink Mode (Mode1 = 0, Mode0 = 1, and the pin’s
Data Register = 0)
Q1 and Q3 are OFF. Q2 is ON. The GPIO pin is capable of
sinking 8 mA of current.
• High Sink Mode (Mode1 = 1, Mode0 = 1, and the pin’s Data
Register = 0)
Q1 and Q3 are OFF. Q2 is ON. The GPIO pin is capable of
sinking 50 mA of current.
• High Drive Mode (Mode1 = 0 or 1, Mode0 = 1, and the pin’s
Data Register = 1)
Q1 and Q2 are OFF. Q3 is ON. The GPIO pin is capable of
sourcing 2 mA of current.
• Resistive Mode (Mode1 = 1, Mode0 = 0, and the pin’s Data
Register = 1)
Q2 and Q3 are OFF. Q1 is ON. The GPIO pin is pulled up
with an internal 14-kΩ resistor.
Note that open drain mode can be achieved by fixing the Data
and Mode1 Registers LOW, and switching the Mode0 register.
Input thresholds are CMOS, or TTL as shown in the table (See
Section 25.0 for the input threshold voltage in TTL or CMOS
modes). Both input modes include hysteresis to minimize
noise sensitivity. In suspend mode, if a pin is used for a
wake-up interrupt using an external R-C circuit, CMOS mode
is preferred for lowest power.
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Table 12-1. Ports 0 and 1 Output Control Truth Table
Data
Register
0
1Hi-ZTTL
0
1High DriveCMOS
0
1ResistiveCMOS
0
1High DriveCMOS
Mode1 Mode0 Output Drive
00
01
10
11
Strength
Hi-ZCMOS
Medium
(8 mA) Sink
Low (2 mA)
Sink
High (50 mA)
Sink
Input
Threshold
CMOS
CMOS
CMOS
12.1Auxiliary Input Port
Port 2 serves as an auxiliary input port as shown in
Figure 12-8. The Port 2 inputs all have TTL input thresholds.
Bit #76543210
Reserved P2.1
Bit
ReservedD+
Name
Read/
Write
Reset 00 00 00 00
Bit [7:6]: Reserved
Bit [5:4]: D+ (SCLK) and D– (SDATA) States
Bit [3:2]: Reserved
Bit 1: P2.1 (Internal Clock Mode Only)
Bit 0: P2.0/VREG Pin State
-- R R -- R R
Figure 12-8. Port 2 Data Register (Address 0x02)
The state of the D+ and D– pins can be read at Port 2 Data
Register. Performing a read from the port pins returns their
logic values.
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
In the Internal Clock mode, the XTALIN pin can serve as a
general purpose input, and its state can be read at Port 2,
Bit 1 (P2.1). See Section 9.1 for more details.
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
In PS/2 mode, the VREG
its state can be read at port P2.0. Section 15.0 for more
details.
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
(SCLK)
State
D–
(SDATA)
State
pin can be used as an input and
(Internal
Clock
Mode
Only)
P2.0
VREG
Pin
Stat e
13.0 USB Serial Interface Engine (SIE)
The SIE allows the microcontroller to communicate with the
USB host. The SIE simplifies the interface between the microcontroller and USB by incorporating hardware that handles the
following USB bus activity independently of the microcontroller:
• Translate the encoded received data and format the data to
be transmitted on the bus.
• CRC checking and generation. Flag the microcontroller if
errors exist during transmission.
• Address checking. Ignore the transactions not addressed
to the device.
• Send appropriate ACK/NAK/STALL handshakes.
• Token type identification (SETUP, IN, or OUT). Set the appropriate token bit once a valid token is received.
• Place valid received data in the appropriate endpoint FIFOs.
• Send and update the data toggle bit (Data1/0).
• Bit stuffing/unstuffing.
Firmware is required to handle the rest of the USB interface
with the following tasks:
• Coordinate enumeration by decoding USB device requests.
• Fill and empty the FIFOs.
• Suspend/Resume coordination.
• Verify and select Data toggle values.
13.1USB Enumeration
A typical USB enumeration sequence is shown below. In this
description, ‘Firmware’ refers to embedded firmware in the
CY7C637xxC controller.
1. The host computer sends a SETUP packet followed by a
DATA packet to USB address 0 requesting the Device descriptor.
2. Firmware decodes the request and retrieves its Device
descriptor from the program memory tables.
3. The host computer performs a control read sequence and
Firmware responds by sending the Device descriptor over
the USB bus, via the on-chip FIFO.
4. After receiving the descriptor, the host sends a SETUP
packet followed by a DATA packet to address 0 assigning
a new USB address to the device.
5. Firmware stores the new address in its USB Device
Address Register after the no-data control sequence
completes.
6. The host sends a request for the Device descriptor using
the new USB address.
7. Firmware decodes the request and retrieves the Device
descriptor from program memory tables.
8. The host performs a control read sequence and Firmware
responds by sending its Device descriptor over the USB
bus.
9. The host generates control reads from the device to request
the Configuration and Report descriptors.
10.Once the device receives a Set Configuration request, its
functions may now be used.
11.Firmware should take appropriate action for Endpoint 1
and/or 2 transactions, which may occur from this point.
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13.2USB Port Status and Control
USB status and control is regulated by the USB Status and
Control Register as shown in Figure 13-1.
Bit #76 5 4 3 2:0
Bit
PS/2
VREG
Name
Pull-up
Enable
Enable
Read/
R/WR/WR/W-R/WR/W
Write
Reset00 0 0 0000
Figure 13-1. USB Status and Control Register (Address
Bit 7: PS/2 Pull-up Enable
This bit is used to enable the internal PS/2 pull-up resistors
on the SDATA and SCLK pins. Normally the output high
level on these pins is V
clamped to approximately 1 Volt above V
Enable bit is set, or if the Device Address is enabled (bit 7
of the USB Device Address Register, Figure 14-1).
1 = Enable PS/2 Pull-up resistors. The SDATA and SCLK
pins are pulled up internally to V
approximately 5 kΩ (see Section 25.0 for the value of
R
).
PS2
0 = Disable PS/2 Pull-up resistors.
Bit 6: V
REG
Enable
A 3.3V voltage regulator is integrated on chip to provide a
voltage source for a 1.5-kΩ pull-up resistor connected to
the D– pin as required by the USB Specification. Note that
the VREG output has an internal series resistance of approximately 200Ω, the external pull-up resistor required is
approximately 1.3-kΩ (see Figure 16-1).
1 = Enable the 3.3V output voltage on the VREG pin.
0 = Disable. The VREG pin can be configured as an input.
Bit 5: USB-PS/2 Interrupt Select
This bit allows the user to select whether an USB bus reset
interrupt or a PS/2 activity interrupt will be generated when
the interrupt conditions are detected.
USB
Reset-
PS/2
Reserved USB
Bus
Activity
Activity
Interrupt
Mode
0x1F)
, but note that the output will be
CC
REG
with two resistors of
CC
D+/D–
Forcing
Bit
if the VREG
1 = PS/2 interrupt mode. A PS/2 activity interrupt will occur
if the SDATA pin is continuously LOW for 128 to 256 µs.
0 = USB interrupt mode (default state). In this mode, a USB
bus reset interrupt will occur if the single ended zero (SE0,
D– and D+ are LOW) exists for 128 to 256 µs.
See Section 21.3 for more details.
Bit 4: Reserved. Must be written as a ‘0’.
Bit 3: USB Bus Activity
The Bus Activity bit is a “sticky” bit that detects any non-idle
USB event has occurred on the USB bus. Once set to HIGH
by the SIE to indicate the bus activity, this bit retains its
logical HIGH value until firmware clears it. Writing a ‘0’ to
this bit clears it; writing a ‘1’ preserves its value. The user
firmware should check and clear this bit periodically to detect any loss of bus activity. Firmware can clear the Bus
Activity bit, but only the SIE can set it. The 1.024-ms timer
interrupt service routine is normally used to check and clear
the Bus Activity bit.
1 = There has been bus activity since the last time this bit
was cleared. This bit is set by the SIE.
0 = No bus activity since last time this bit was cleared (by
firmware).
Bit [2:0]: D+/D– Forcing Bit [2:0]
Forcing bits allow firmware to directly drive the D+ and D–
pins, as shown in Table 13-1. Outputs are driven with controlled edge rates in these modes for low EMI. For forcing
the D+ and D– pins in USB mode, D+/D– Forcing Bit 2
should be 0. Setting D+/D– Forcing Bit 2 to ‘1’ puts both
pins in an open-drain mode, preferred for applications such
as PS/2 or LED driving.
Table 13-1. Control Modes to Force D+/D– Outputs
D+/D– Forcing
Control ActionApplication
Bit [2:0]
000Not forcing (SIE controls driver) Any Mode
001Force K (D+ HIGH, D– LOW)USB Mode
010Force J (D+ LOW, D– HIGH)
011Force SE0 (D– LOW, D+ LOW)
100Force D– LOW, D+ LOWPS/2 Mode
101Force D– LOW, D+ HiZ
110Force D– HiZ, D+ LOW
111Force D– HiZ, D+ HiZ
[2]
Note:
2. For PS/2 operation, the D+/D– Forcing Bit [2:0] = 111b mode must be set initially (one time only) before using the other PS/2 force modes.
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14.0 USB Device
The CY7C637xxC supports one USB Device Address with
three endpoints: EP0, EP1, and EP2.
14.1USB Address Register
The USB Device Address Register contains a 7-bit USB
address and one bit to enable USB communication. This
register is cleared during a reset, setting the USB device
address to zero and marking this address as disabled.
Figure 14-1 shows the format of the USB Address Register.
Bit #7 6543210
Bit NameDevice
Address
Enable
Read/WriteR/WR/W R/W R/W R/W R/W R/W R/W
Reset0 0000000
Figure 14-1. USB Device Address Register (Address 0x10)
In either USB or PS/2 mode, this register is cleared by both
hardware resets and the USB bus reset. See Section 21.3 for
more information on the USB Bus Reset – PS/2 interrupt.
Bit 7: Device Address Enable
This bit must be enabled by firmware before the serial interface engine (SIE) will respond to USB traffic at the address specified in Bit [6:0].
1 = Enable USB device address.
0 = Disable USB device address.
Bit [6:0]: Device Address Bit [6:0]
These bits must be set by firmware during the USB enumeration process (i.e., SetAddress) to the non-zero address
assigned by the USB host.
14.2USB Control Endpoint
All USB devices are required to have an endpoint number 0
(EP0) that is used to initialize and control the USB device. EP0
provides access to the device configuration information and
allows generic USB status and control accesses. EP0 is
bidirectional as the device can both receive and transmit data.
EP0 uses an 8-byte FIFO at SRAM locations 0xF8-0xFF, as
shown in Section 8.2.
The EP0 endpoint mode register uses the format shown in
Figure 14-2.
The SIE provides a locking feature to prevent firmware from
overwriting bits in the USB Endpoint 0 Mode Register. Writes
to the register have no effect from the point that Bit[6:0] of the
register are updated (by the SIE) until the firmware reads this
register. The CPU can unlock this register by reading it.
Because of these hardware-locking features, firmware should
perform an read after a write to the USB Endpoint 0 Mode
Register and USB Endpoint 0 Count Register (Figure 14-4) to
verify that the contents have changed as desired, and that the
SIE has not updated these values.
Bit [7:4] of this register are cleared by any non-locked write to
this register, regardless of the value written.
Bit 7: SETUP Received
1 = A valid SETUP packet has been received. This bit is
forced HIGH from the start of the data packet phase of the
SETUP transaction until the start of the ACK packet returned by the SIE. The CPU is prevented from clearing this
bit during this interval. While this bit is set to ‘1’, the CPU
cannot write to the EP0 FIFO. This prevents firmware from
overwriting an incoming SETUP transaction before firmware has a chance to read the SETUP data.
0 = No SETUP received. This bit is cleared by any
non-locked writes to the register.
Bit 6: IN Received
1 = A valid IN packet has been received. This bit is updated
to ‘1’ after the last received packet in an IN transaction. This
bit is cleared by any non-locked writes to the register.
0 = No IN received. This bit is cleared by any non-locked
writes to the register.
Bit 5: OUT Received
1 = A valid OUT packet has been received. This bit is updated to ‘1’ after the last received packet in an OUT transaction. This bit is cleared by any non-locked writes to the
register.
0 = No OUT received. This bit is cleared by any non-locked
writes to the register.
Bit 4: ACKed Transaction
The ACKed Transaction bit is set whenever the SIE engages in a transaction to the register's endpoint that completes
with an ACK packet.
1 = The transaction completes with an ACK.
0 = The transaction does not complete with an ACK.
Bit [3:0]: Mode Bit[3:0]
The endpoint modes determine how the SIE responds to
USB traffic that the host sends to the endpoint. For example, if the endpoint Mode Bits [3:0] are set to 0001 which is
NAK IN/OUT mode as shown in Table 22-1, the SIE will
send NAK handshakes in response to any IN or OUT token
sent to this endpoint. In this NAK IN/OUT mode, the SIE will
send an ACK handshake when the host sends a SETUP
token to this endpoint. The mode encoding is shown in
Table 22-1. Additional information on the mode bits can be
found in Table 22-2 and Table 22-3. These modes give the
firmware total control on how to respond to different tokens
sent to the endpoints from the host.
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In addition, the Mode Bits are automatically changed by the
SIE in response to many USB transactions. For example, if
the Mode Bit [3:0] are set to 1011 which is ACK OUT-NAK
IN mode as shown in Table 22-1, the SIE will change the
endpoint Mode Bit [3:0] to NAK IN/OUT (0001) mode after
issuing an ACK handshake in response to an OUT token.
Firmware needs to update the mode for the SIE to respond
appropriately.
14.3USB Non-control Endpoints
The CY7C637xxC feature two non-control endpoints, endpoint
1 (EP1) and endpoint 2 (EP2). The EP1 and EP2 Mode
Registers do not have the locking mechanism of the EP0
Mode Register. The EP1 and EP2 Mode Registers use the
format shown in Figure 14-3. EP1 uses an 8-byte FIFO at
SRAM locations 0xF0–0xF7, EP2 uses an 8-byte FIFO at
SRAM locations 0xE8–0xEF as shown in Section 8.2.
Bit #7 6543210
Bit
STALL ReservedACKed
Name
Read/
Write
Reset0 0000000
Figure 14-3. USB Endpoint EP1, EP2 Mode Registers (Ad-
Bit 7: STALL
Bit [6:5]: Reserved. Must be written to zero during register
writes.
R/W--R/CR/W R/W R/W R/W
dresses 0x14 and 0x16)
1 = The SIE will stall an OUT packet if the Mode Bits are set
to ACK-OUT, and the SIE will stall an IN packet if the mode
bits are set to ACK-IN. See Section 22.0 for the available
modes.
0 = This bit must be set to LOW for all other modes.
Transaction
Mode Bit
14.4USB Endpoint Counter Registers
There are three Endpoint Counter registers, with identical
formats for both control and non-control endpoints. These
registers contain byte count information for USB transactions,
as well as bits for data packet status. The format of these
registers is shown in Figure 14-4.
Bit #76 5 4 3210
Bit NameData
Toggle
Read/WriteR/WR/W--R/WR/WR/WR/
Reset00 0 0 0000
Figure 14-4. Endpoint 0,1,2 Counter Registers
(Addresses 0x11, 0x13 and 0x15)
Bit 7: Data Toggle
This bit selects the DATA packet's toggle state. For IN
transactions, firmware must set this bit to the select the
transmitted Data Toggle. For OUT or SETUP transactions,
the hardware sets this bit to the state of the received Data
Toggle bit.
1 = DATA1
0 = DATA0
Bit 6: Data Valid
This bit is used for OUT and SETUP tokens only. This bit is
cleared to ‘0’ if CRC, bitstuff, or PID errors have occurred.
This bit does not update for some endpoint mode settings.
Refer to Table 22-3 for more details.
1 = Data is valid.
0 = Data is invalid. If enabled, the endpoint interrupt will
occur even if invalid data is received.
Bit [5:4]: Reserved
Data
Val id
ReservedByte Count
W
Bit 4: ACKed Transaction
The ACKed transaction bit is set whenever the SIE engages in a transaction to the register's endpoint that completes
with an ACK packet.
1 = The transaction completes with an ACK.
0 = The transaction does not complete with an ACK.
Bit [3:0]: Mode Bit [3:0]
The EP1 and EP2 Mode Bits operate in the same manner
as the EP0 Mode Bits (see Section 14.2).
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Bit [3:0]: Byte Count Bit [3:0]
Byte Count Bits indicate the number of data bytes in a
transaction: For IN transactions, firmware loads the count
with the number of bytes to be transmitted to the host from
the endpoint FIFO. Valid values are 0 to 8 inclusive. For
OUT or SETUP transactions, the count is updated by hardware to the number of data bytes received, plus 2 for the
CRC bytes. Valid values are 2 to 10 inclusive.
For Endpoint 0 Count Register, whenever the count updates from a SETUP or OUT transaction, the count register
locks and cannot be written by the CPU. Reading the register unlocks it. This prevents firmware from overwriting a
status update on incoming SETUP or OUT transactions before firmware has a chance to read the data.
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15.0 USB Regulator Output
The VREG pin provides a regulated output for connecting the
pull-up resistor required for USB operation. For USB, a 1.5-kΩ
resistor is connected between the D– pin and the V
voltage, to indicate low-speed USB operation. Since the
VREG output has an internal series resistance of approximately 200Ω, the external pull-up resistor required is R
Section 25.0).
The regulator output is placed in a high-impedance state at
reset, and must be enabled by firmware by setting the VREG
Enable bit in the USB Status and Control Register
(Figure 13-1). This simplifies the design of a combination
PS/2-USB device, since the USB pull-up resistor can be left in
place during PS/2 operation without loading the PS/2 line. In
this mode, the V
can be read at port P2.0. Refer to Figure 12-8 for the Port 2
pin can be used as an input and its state
REG
data register. This input has a TTL threshold.
In suspend mode, the regulator is automatically disabled. If
VREG Enable bit is set (Figure 13-1), the VREG pin is pulled
up to V
proper V
with an internal 6.2-kΩ resistor. This holds the
CC
state in suspend mode
OH
Note that enabling the device for USB (by setting the Device
Address Enable bit, Figure 14-1) activates the internal
regulator, even if the VREG Enable bit is cleared to 0. This
insures proper USB signaling in the case where the VREG pin
is used as an input, and an external regulator is provided for
the USB pull-up resistor. This also limits the swing on the D–
and D+ pins to about 1V above the internal regulator voltage,
so the Device Address Enable bit normally should only be set
for USB operating modes.
The regulator output is only designed to provide current for the
USB pull-up resistor. In addition, the output voltage at the
PU
REG
(see
VREG pin is effectively disconnected when the CY7C637xxC
device transmits USB from the internal SIE. This means that
the VREG pin does not provide a stable voltage during
transmits, although this does not affect USB signaling.
16.0 PS/2 Operation
The CY7C637xxC parts are optimized for combination USB or
PS/2 devices, through the following features:
1. USB D+ and D– lines can also be used for PS/2 SCLK and
SDATA pins, respectively. With USB disabled, these lines
can be placed in a high-impedance state that will pull up to
V
. (Disable USB by clearing the Address Enable bit of
CC
the USB Device Address Register, Figure 14-1).
2. An interrupt is provided to indicate a long LOW state on the
SDATA pin. This eliminates the need to poll this pin to check
for PS/2 activity. Refer to Section 21.3 for more details.
3. Internal PS/2 pull-up resistors can be enabled on the SCLK
and SDATA lines, so no GPIO pins are required for this task
(bit 7, USB Status and Control Register, Figure 13-1).
4. The controlled slew rate outputs from these pins apply to
both USB and PS/2 modes to minimize EMI.
5. The state of the SCLK and SDATA pins can be read, and
can be individually driven LOW in an open drain mode. The
pins are read at bits [5:4] of Port 2, and are driven with the
Control Bits [2:0] of the USB Status and Control Register.
6. The V
so that a USB pull-up resistor on the D–/SDATA pin will not
interfere with PS/2 operation (bit 6, USB Status and Control
Register).
The PS/2 on-chip support circuitry is illustrated in Figure 16-1.
pin can be placed into a high-impedance state,
REG
Port 2.0
VREG Enable
3.3V
200Ω
Regulator
V
CC
PS/2 Pull-up
Enable
5 kΩ
5 kΩ
USB - PS/2
Driver
Port 2.5
Port 2.4
On-chip Off-chip
Figure 16-1. Diagram of USB-PS/2 System Connections
VREG
1.3 kΩ
D+/SCLK
D–/SDATA
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17.0 Serial Peripheral Interface (SPI)
SPI is a four-wire, full-duplex serial communication interface
between a master device and one or more slave devices. The
CY7C637xxC SPI circuit supports byte serial transfers in
either Master or Slave modes. The block diagram of the SPI
circuit is shown in Figure 17-1. The block contains buffers for
Data Bus
TX Buffer
8 bit shift register
RX Buffer
Data Bus
Write
Read
Figure 17-1. SPI Block Diagram
both transmit and receive data for maximum flexibility and
throughput. The CY7C637xxC can be configured as either an
SPI Master or Slave. The external interface consists of
Master-Out/Slave-In (MOSI), Master-In/Slave-Out (MISO),
Serial Clock (SCK), and Slave Select (SS
SPI modes are activated by setting the appropriate bits in the
SPI Control Register, as described below.
).
MOSI
Master
/ Slave
Control
MISO
SCK
SS
4
Internal SCK
The SPI Data Register below serves as a transmit and receive
buffer.
Bit #76543210
Bit NameData I/O
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Reset00000000
Figure 17-2. SPI Data Register (Address 0x60)
Bit [7:0]: Data I/O[7:0]
Writes to the SPI Data Register load the transmit buffer,
while reads from this register read the receive buffer contents.
1 = Logic HIGH
0 = Logic LOW
17.1Operation as an SPI Master
Only an SPI Master can initiate a byte/data transfer. This is
done by the Master writing to the SPI Data Register. The
Master shifts out 8 bits of data (MSB first) along with the serial
clock SCK for the Slave. The Master’s outgoing byte is
replaced with an incoming one from a Slave device. When the
last bit is received, the shift register contents are transferred
to the receive buffer and an interrupt is generated. The receive
data must be read from the SPI Data Register before the next
byte of data is transferred to the receive buffer, or the data will
be lost.
When operating as a Master, an active LOW Slave Select (SS
must be generated to enable a Slave for a byte transfer. This
Slave Select is generated under firmware control, and is not
part of the SPI internal hardware. Any available GPIO can be
used for the Master’s Slave Select output.
When the Master writes to the SPI Data Register, the data is
loaded into the transmit buffer. If the shift register is not busy
shifting a previous byte, the TX buffer contents will be automatically transferred into the shift register and shifting will begin.
If the shift register is busy, the new byte will be loaded into the
shift register only after the active byte has finished and is transferred to the receive buffer. The new byte will then be shifted
out. The Transmit Buffer Full (TBF) bit will be set HIGH until
the transmit buffer’s data-byte is transferred to the shift
register. Writing to the transmit buffer while the TBF bit is HIGH
will overwrite the old byte in the transmit buffer.
The byte shifting and SCK generation are handled by the
hardware (based on firmware selection of the clock source).
Data is shifted out on the MOSI pin (P0.5) and the serial clock
is output on the SCK pin (P0.7). Data is received from the slave
on the MISO pin (P0.6). The output pins must be set to the
desired drive strength, and the GPIO data register must be set
to 1 to enable a bypass mode for these pins. The MISO pin
must be configured in the desired GPIO input mode. See
Section 12.0 for GPIO configuration details.
17.2Master SCK Selection
The Master’s SCK is programmable to one of four clock
settings, as shown in Figure 17-1. The frequency is selected
with the Clock Select Bits of the SPI control register. The
)
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hardware provides 8 output clocks on the SCK pin (P0.7) for
each byte transfer. Clock phase and polarity are selected by
the CPHA and CPOL control bits (see Figure 17-1 and 17-4).
The master SCK duty cycle is nominally 33% in the fastest (2
Mbps) mode, and 50% in all other modes.
17.3Operation as an SPI Slave
In slave mode, the chip receives SCK from an external master
on pin P0.7. Data from the master is shifted in on the MOSI pin
(P0.5), while data is being shifted out of the slave on the MISO
pin (P0.6). In addition, the active LOW Slave Select must be
asserted to enable the slave for transmit. The Slave Select pin
is P0.4. These pins must be configured in appropriate GPIO
modes, with the GPIO data register set to 1 to enable bypass
mode selected for the MISO pin.
In Slave mode, writes to the SPI Data Register load the
Transmit buffer. If the Slave Select is asserted (SS
the shift register is not busy shifting a previous byte, the
transmit buffer contents will be automatically transferred into
the shift register. If the shift register is busy, the new byte will
be loaded into the shift register only after the active byte has
finished and is transferred to the receive buffer. The new byte
is then ready to be shifted out (shifting waits for SCK from the
Master). If the Slave Select is not active when the transmit
buffer is loaded, data is not transferred to the shift register until
Slave Select is asserted. The Transmit Buffer Full (TBF) bit will
be set to ‘1’ until the transmit buffer’s data-byte is transferred
to the shift register. Writing to the transmit buffer while the TBF
bit is HIGH will overwrite the old byte in the Transmit Buffer.
If the Slave Select is deasserted before a byte transfer is
complete, the transfer is aborted and no interrupt is generated.
Whenever Slave Select is asserted, the transmit buffer is
automatically reloaded into the shift register.
Clock phase and polarity must be selected to match the SPI
master, using the CPHA and CPOL control bits (see
Figure 17-3 and Figure 17-4).
The SPI slave logic continues to operate in suspend, so if the
SPI interrupt is enabled, the device can go into suspend during
a SPI slave transaction, and it will wake up at the interrupt that
signals the end of the byte transfer.
LOW) and
17.4SPI Status and Control
The SPI Control Register is shown in Figure 17-3. The timing
diagram in Figure 17-4 shows the clock and data states for the
various SPI modes.
Bit #76543 210
Bit Name TCMP TBFComm
Mode[1:0]
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Reset00000 000
Figure 17-3. SPI Control Register (Address 0x61)
Bit 7: TCMP
1 = TCMP is set to 1 by the hardware when 8-bit transfer is
complete. The SPI interrupt is asserted at the same time
TCMP is set to 1.
0 = This bit is only cleared by firmware.
Bit 6: TBF
Transmit Buffer Full bit.
1 = Indicates data in the transmit buffer has not transferred
to the shift register.
0 = Indicates data in the transmit buffer has transferred to
the shift register.
Bit [5:4] Comm Mode[1:0]
00 = All communications functions disabled (default).
01 = SPI Master Mode.
10 = SPI Slave Mode.
11 = Reserved.
Bit 3: CPOL
SPI Clock Polarity bit.
1 = SCK idles HIGH.
0 = SCK idles LOW.
Bit 2: CPHA
SPI Clock Phase bit (see Figure 17-4)
Bit [1:0]: SCK Select
Master mode SCK frequency selection (no effect in Slave
Mode):
00 = 2 Mbit/s
01 = 1 Mbit/s
10 = 0.5 Mbit/s
11 = 0.0625 Mbit/s
CPOL CPHASCK
Select
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SCK (CPOL = 0)
SCK (CPOL = 1)
SS
CPHA = 0:
MOSI/MISO
Data Capture Strobe
Interrupt Issued
CPHA = 1:
MOSI/MISO
Data Capture Strobe
Interrupt Issued
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MSBLSB
MSBLSB
Figure 17-4. SPI Data Timing
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x
17.5SPI Interrupt
For SPI, an interrupt request is generated after a byte is
received or transmitted. See Section 21.3 for details on the SPI
interrupt.
17.6SPI Modes for GPIO Pins
The GPIO pins used for SPI outputs (P0.5–P0.7) contain a
bypass mode, as shown in the GPIO block diagram
(Figure 12-1). Whenever the SPI block is inactive (Mode[5:4]
= 00), the bypass value is 1, which enables normal GPIO
Table 17-1. SPI Pin Assignments
SPI FunctionGPIO PinComment
Slave Select (SS
Master Out, Slave In (MOSI)P0.5Data output for master, data input for slave.
Master In, Slave Out (MISO)P0.6Data input for master, data output for slave.
SCKP0.7SPI Clock: Output for master, input for slave.
)P0.4For Master Mode, Firmware sets SS, may use any GPIO pin.
operation. When SPI master or slave modes are activated, the
appropriate bypass signals are driven by the hardware for
outputs, and are held at 1 for inputs. Note that the corre-
sponding data bits in the Port 0 Data Register must be set
to 1 for each pin being used for an SPI output. In addition,
the GPIO modes are not affected by operation of the SPI
block, so each pin must be programmed by firmware to the
desired drive strength mode.
For GPIO pins that are not used for SPI outputs, the SPI
bypass value in Figure 12-1 is always 1, for normal GPIO
operation.
For Slave Mode, SS
is an active LOW input.
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18.0 12-bit Free-running Timer
The 12-bit timer operates with a 1-µs tick, provides two interrupts (128-µs and 1.024-ms) and allows the firmware to
directly time events that are up to 4 ms in duration. The lower
eight bits of the timer can be read directly by the firmware.
Reading the lower eight bits latches the upper four bits into a
temporary register. When the firmware reads the upper four
bits of the timer, it is actually reading the count stored in the
temporary register. The effect of this is to ensure a stable 12-bit
timer value can be read, even when the two reads are
separated in time.
Bit #76543210
Bit NameTimer [7:0]
Read/WriteRRRRRRRR
Reset00000000
Figure 18-1. Timer LSB Register (Address 0x24)
10978
6432
5
Bit [7:0]: Timer lower eight bits
Bit #76543210
Bit NameReservedTimer [11:8]
Read/Write----RRRR
Reset00000000
Figure 18-2. Timer MSB Register (Address 0x25)
Bit [7:4]: Reserved
Bit [3:0]: Timer upper four bits
1.024-ms interrupt
µs interrupt
128-
1011
1 MHz clock
L1L0L2L3
D3D2D1D0D7D6D5D4D3D2D1D0
8
Figure 18-3. Timer Block Diagram
To Timer Registers
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19.0 Timer Capture Registers
Four 8-bit capture timer registers provide both rising- and
falling-edge event timing capture on two pins. Capture Timer
A is connected to Pin 0.0, and Capture Timer B is connected
to Pin 0.1. These can be used to mark the time at which a rising
or falling event occurs at the two GPIO pins. Each timer will
Free-running Timer
111098743210
Prescaler
Mux
GPIO
P0.0
First Edge Hold
Bit 7, Reg 0x44
Rising
Edge
Detect
Falling
Edge
Detect
capture eight bits of the free-running timer into its Capture
Timer Data Register if a rising or falling edge event that
matches the specified rising or falling edge condition at the pin.
A prescaler allows selection of the capture timer tick size.
Interrupts can be individually enabled for the four capture
registers. A block diagram is shown in Figure 19-1.
65
1 MHz
Clock
8-bit Capture Registers
Timer A Rising Edge Time
Timer A Falling Edge Time
Rising
Edge
GPIO
P0.1
Detect
Falling
Edge
Detect
Capture A Rising Int Enable
Bit 0, Reg 0x44
Capture A Falling Int Enable
Bit 1, Reg 0x44
Capture B Rising Int Enable
Bit 2, Reg 0x44
Capture B Falling Int Enable
Bit 3, Reg 0x44
Figure 19-1. Capture Timers Block Diagram
The four Capture Timer Data Registers are read-only, and are
shown in Figure 19-2 through Figure 19-5.
Out of the 12-bit free running timer, the 8-bit captured in the
Capture Timer Data Registers are determined by the Prescale
Bit [2:0] in the Capture Timer Configuration Register
(Figure 19-7).
.
Timer B Rising Edge Time
Timer B Falling Edge Time
Capture Timer A Interrupt Request
Capture Timer B Interrupt Request
Bit #76543210
Bit NameCapture A Rising Data
Read/WriteRRRRRRRR
Reset00000000
Figure 19-2. Capture Timer A-Rising, Data Register
(Address 0x40)
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Bit #76543210
Bit NameCapture A Falling Data
Read/WriteRRRRRRRR
Reset00000000
Figure 19-3. Capture Timer A-Falling, Data Register
(Address 0x41)
Bit #76543210
Bit NameCapture B Rising Data
Read/WriteRRRRRRRR
Reset00000000
Figure 19-4. Capture Timer B-Rising, Data Register
(Address 0x42)
Bit #76543210
Bit NameCapture B Falling Data
Read/WriteRRRRRRRR
Reset00000000
Figure 19-5. Capture Timer B-Falling, Data Register
(Address 0x43)
Bit #76543210
Bit
Name
Read/
ReservedCapture
Falling
Event
B
Capture
B
Rising
Event
Capture
A
Falling
Event
Capture
A
Rising
Event
---- RRRR
Write
Reset 00000000
Figure 19-6. Capture Timer Status Register (Address 0x45)
Bit [7:4]: Reserved.
Bit [3:0]: Capture A/B, Falling/Rising Event
These bits record the occurrence of any rising or falling
edges on the capture GPIO pins. Bits in this register are
cleared by reading the corresponding data register.
1 = A rising or falling event that matches the pin’s rising/falling condition has occurred.
0 = No event that matches the pin’s rising or falling edge
condition.
Because both Capture A events (rising and falling) share
an interrupt, user’s firmware needs to check the status of
both Capture A Falling and Rising Event bits to determine
what caused the interrupt. This is also true for Capture B
events.
Bit #7654 3210
B
Int
Capture
B
Rising
Int
Enable
Bit
First
Name
Edge
Hold
Prescale Bit
[2:0]
Capture
Falling
Enable
Read/
R/W R/W R/W R/W R/WR/WR/WR/W
Capture
Falling
Enable
A
Int
Capture
A
Rising
Int
Enable
Write
Reset0000 0000
Figure 19-7. Capture Timer Configuration Register
(Address 0x44)
Bit 7: First Edge Hold
1 = The time of the first occurrence of an edge is held in the
Capture Timer Data Register until the data is read. Subsequent edges are ignored until the Capture Timer Data Register is read.
0 = The time of the most recent edge is held in the Capture
Timer Data Register. That is, if multiple edges have occurred before reading the capture timer, the time for the last
one will be read (default state).
The First Edge Hold function applies globally to all four capture timers.
Bit [6:4]: Prescale Bit [2:0]
Three prescaler bits allow the capture timer clock rate to be
selected among 5 choices, as shown in Ta bl e 19 -1 below.
Bit [3:0]: Capture A/B, Rising/Falling Interrupt Enable
Each of the four Capture Timer registers can be individually
enabled to provide interrupts.
Both Capture A events share a common interrupt request,
as do the two Capture B events. In addition to the event
enables, the main Capture Interrupt Enables bit in the Global Interrupt Enable register (Section 21.0) must be set to
activate a capture interrupt.
1 = Enable interrupt
0 = Disable interrupt
Table 19-1. Capture Timer Prescalar Settings (Step size
and range for F
= 6 MHz)
CLK
LSB
Prescale
2:0Captured Bits
Step
SizeRange
000Bits 7:0 of free-running timer1 µs256 µs
001Bits 8:1 of free-running timer2 µs512 µs
010Bits 9:2 of free-running timer4 µs1.024 ms
011Bits 10:3 of free-running timer8 µs2.048 ms
100Bits 11:4 of free-running timer16 µs4.096 ms
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20.0 Processor Status and Control Register
Bit #76543210
Bit NameIRQ
Pending
Read/WriteRR/WR/WR/WR/WR-R/W
Reset01010001
Watchdog
Reset
Bus
Interrupt
Event
LVR/BOR
Reset
SuspendInterrupt
Enable
Sense
Figure 20-1. Processor Status and Control Register (Address 0xFF)
ReservedRun
Bit 7: IRQ Pending
When an interrupt is generated, it is registered as a pending
interrupt. The interrupt will remain pending until its interrupt
enable bit is set (Figure 21-1 and Figure 21-2) and interrupts are globally enabled (Bit 2, Processor Status and
Control Register). At that point the internal interrupt handling sequence will clear the IRQ Pending bit until another
interrupt is detected as pending. This bit is only valid if the
Global Interrupt Enable bit is disabled.
1 = There are pending interrupts.
0 = No pending interrupts.
Bit 6: Watchdog Reset
The Watchdog Timer Reset (WDR) occurs when the internal Watchdog timer rolls over. The timer will roll over and
WDR will occur if it is not cleared within t
26.0 for the value of t
LVR/BOR. Note that a Watchdog reset can occur with a
). This bit is cleared by an
WATCH
WATCH
(see Section
POR/LVR/BOR event, as discussed at the end of this section.
1 = A Watchdog reset occurs.
0 = No Watchdog reset
Bit 5: Bus Interrupt Event
The Bus Reset Status is set whenever the event for the
USB Bus Reset or PS/2 Activity interrupt occurs. The event
type (USB or PS/2) is selected by the state of the USB-PS/2
Interrupt Mode bit in the USB Status and Control Register
(see Figure 13-1). The details on the event conditions that
set this bit are given in Section 21.3. In either mode, this bit
is set as soon as the event has lasted for 128–256 µs, and
the bit will be set even if the interrupt is not enabled. The bit
is only cleared by firmware or LVR/WDR.
1 = A USB reset occurred or PS/2 Activity is detected, depending on USB-PS/2 Interrupt Select bit.
0 = No event detected since last cleared by firmware or
LVR/WDR.
Bit 4: LVR/BOR Reset
The Low-voltage or Brown-out Reset is set to ‘1’ during a
power-on reset. Firmware can check bits 4 and 6 in the
reset handler to determine whether a reset was caused by
a LVR/BOR condition or a Watchdog timeout. This bit is not
affected by WDR. Note that a LVR/BOR event may be followed by a Watchdog reset before firmware begins executing, as explained at the end of this section.
1 = A POR or LVR has occurred.
0 = No POR nor LVR since this bit last cleared.
Bit 3: Suspend
Writing a '1' to the Suspend bit will halt the processor and
cause the microcontroller to enter the suspend mode that
significantly reduces power consumption. An interrupt or
USB bus activity will cause the device to come out of suspend. After coming out of suspend, the device will resume
firmware execution at the instruction following the IOWR
which put the part into suspend. When writing the suspend
bit with a resume condition present (such as non-idle USB
activity), the suspend state will still be entered, followed
immediately by the wake-up process (with appropriate delays for the clock start-up). See Section 11.0 for more details on suspend mode operation.
1 = Suspend the processor.
0 = Not in suspend mode. Cleared by the hardware when
resuming from suspend.
Bit 2: Interrupt Enable Sense
This bit shows whether interrupts are enabled or disabled.
Firmware has no direct control over this bit as writing a zero
or one to this bit position will have no effect on interrupts.
This bit is further gated with the bit settings of the Global
Interrupt Enable Register (Figure 21-1) and USB Endpoint
Interrupt Enable Register (Figure 21-2). Instructions DI, EI,
and RETI manipulate the state of this bit.
1 = Interrupts are enabled.
0 = Interrupts are masked off.
Bit 1: Reserved. Must be written as a 0.
Bit 0: Run
This bit is manipulated by the HALT instruction. When Halt
is executed, the processor clears the run bit and halts at the
end of the current instruction. The processor remains halted until a reset occurs (low-voltage, brown-out, or Watchdog). This bit should normally be written as a ‘1’.
During power-up, or during a low-voltage reset, the Processor
Status and Control Register is set to 00010001, which
indicates a LVR/BOR (bit 4 set) has occurred and no interrupts
are pending (bit 7 clear). Note that during the t
suspend at start-up (explained in Section 10.1), a Watchdog
START
ms partial
Reset will also occur. When a WDR occurs during the
power-up suspend interval, firmware would read 01010001
from the Status and Control Register after power-up. Normally
the LVR/BOR bit should be cleared so that a subsequent WDR
can be clearly identified. Note that if a USB bus reset (long
SE0) is received before firmware examines this register, the
Bus Interrupt Event bit would also be set.
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During a Watchdog Reset, the Processor Status and Control
Register is set to 01XX0001, which indicates a Watchdog
Reset (bit 4 set) has occurred and no interrupts are pending
(bit 7 clear).
21.0 Interrupts
Interrupts can be generated by the GPIO lines, the internal
free-running timer, the SPI block, the capture timers, on
various USB events, PS/2 activity, or by the wake-up timer. All
interrupts are maskable by the Global Interrupt Enable
Register and the USB End Point Interrupt Enable Register.
Writing a ‘1’ to a bit position enables the interrupt associated
with that bit position. During a reset, the contents of the
interrupt enable registers are cleared, along with the Global
Interrupt enable bit of the CPU, effectively disabling all interrupts.
The interrupt controller contains a separate flip-flop for each
interrupt. See Figure 21-3 for the logic block diagram of the
interrupt controller. When an interrupt is generated it is first
registered as a pending interrupt. It will stay pending until it is
serviced or a reset occurs. A pending interrupt will only
generate an interrupt request if it is enabled by the corresponding bit in the interrupt enable registers. The highest
priority interrupt request will be serviced following the
completion of the currently executing instruction.
When servicing an interrupt, the hardware will first disable all
interrupts by clearing the Global Interrupt Enable bit in the
CPU (the state of this bit can be read at Bit 2 of the Processor
Status and Control Register). Next, the flip-flop of the current
interrupt is cleared. This is followed by an automatic CALL
instruction to the ROM address associated with the interrupt
being serviced (i.e., the Interrupt Vector, see Section 21.1).
The instruction in the interrupt table is typically a JMP
instruction to the address of the Interrupt Service Routine
(ISR). The user can re-enable interrupts in the interrupt service
routine by executing an EI instruction. Interrupts can be nested
to a level limited only by the available stack space.
The Program Counter value as well as the Carry and Zero
flags (CF, ZF) are stored onto the Program Stack by the
automatic CALL instruction generated as part of the interrupt
acknowledge process. The user firmware is responsible for
ensuring that the processor state is preserved and restored
during an interrupt. The PUSH A instruction should typically be
used as the first command in the ISR to save the accumulator
value and the POP A instruction should be used just before the
RETI instruction to restore the accumulator value. The
program counter, CF and ZF are restored and interrupts are
enabled when the RETI instruction is executed.
The DI and EI instructions can be used to disable and enable
interrupts, respectively. These instructions affect only the
Global Interrupt Enable bit of the CPU. If desired, EI can be
used to re-enable interrupts while inside an ISR, instead of
waiting for the RETI that exits the ISR. While the global
interrupt enable bit is cleared, the presence of a pending
interrupt can be detected by examining the IRQ Sense bit (Bit
7 in the Processor Status and Control Register).
21.1Interrupt Vectors
The Interrupt Vectors supported by the device are listed in
Table 21-1. The highest priority interrupt is #1 (USB Bus Reset
/ PS/2 activity), and the lowest priority interrupt is #11
(Wake-up Timer). Although Reset is not an interrupt, the first
instruction executed after a reset is at ROM address 0x0000,
which corresponds to the first entry in the Interrupt Vector
Table. Interrupt vectors occupy two bytes to allow for a
two-byte JMP instruction to the appropriate Interrupt Service
Routine (ISR).
Table 21-1. Interrupt Vector Assignments
Interrupt Vec-
tor Number
not applicable0x0000Execution after Reset begins
10x0002USB Bus Reset or PS/2 Activity
20x0004128-µs timer interrupt
30x00061.024-ms timer interrupt
40x0008USB Endpoint 0 interrupt
50x000AUSB Endpoint 1 interrupt
60x000CUSB Endpoint 2 interrupt
70x000ESPI Interrupt
80x0010Capture Timer A interrupt
90x0012Capture Timer B interrupt
100x0014GPIO interrupt
110x0016Wake-up Timer interrupt
ROM
AddressFunction
here
interrupt
21.2Interrupt Latency
Interrupt latency can be calculated from the following
equation:
Interrupt Latency = (Number of clock cycles remaining in the
current instruction)
+ (10 clock cycles for the CALL
instruction)
+ (5 clock cycles for the JMP instruction)
For example, if a 5 clock cycle instruction such as JC is being
executed when an interrupt occurs, the first instruction of the
Interrupt Service Routine will execute a minimum of 16 clocks
(1+10+5) or a maximum of 20 clocks (5+10+5) after the
interrupt is issued. With a 6-MHz external resonator, internal
CPU clock speed is 12 MHz, so 20 clocks take 20/12 MHz =
1.67 µs.
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21.3Interrupt Sources
The following sections provide details on the different types of
interrupt sources.
Bit #76543210
Bit NameWake-up
Interrupt
Enable
Read/WriteR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000
GPIO
Interrupt
Enable
Figure 21-1. Global Interrupt Enable Register (Address 0x20)
Capture
Timer B
Intr. Enable
Capture
Timer A
Intr. Enable
SPI
Interrupt
Enable
1.024-ms
Interrupt
Enable
128-µs
Interrupt
Enable
USB Bus
Reset /
PS/2 Activity
Intr. Enable
Bit 7: Wake-up Interrupt Enable
The internal wake-up timer is normally used to wake the
part from suspend mode, but it can also provide an interrupt
when the part is awake. The wake-up timer is cleared
whenever the Wake-up Interrupt Enable bit is written to a 0,
and runs whenever that bit is written to a 1. When the interrupt is enabled, the wake-up timer provides periodic interrupts at multiples of period, as described in Section 11.2.
1 = Enable wake-up timer for periodic wake-up.
0 = Disable and power-off wake-up timer.
Bit 6: GPIO Interrupt Enable
Each GPIO pin can serve as an interrupt input. During a
reset, GPIO interrupts are disabled by clearing all GPIO
interrupt enable registers. Writing a ‘1’ to a GPIO Interrupt
Enable bit enables GPIO interrupts from the corresponding
input pin. These registers are shown in Figure 21-4 for Port
0 and Figure 21-5 for Port 1. In addition to enabling the
desired individual pins for interrupt, the main GPIO interrupt
must be enabled, as explained in Section 21.0.
The polarity that triggers an interrupt is controlled independently for each GPIO pin by the GPIO Interrupt Polarity
Registers. Setting a Polarity bit to ‘0’ allows an interrupt on
a falling GPIO edge, while setting a Polarity bit to ‘1’ allows
an interrupt on a rising GPIO edge. The Polarity Registers
reset to 0 and are shown in Figure 21-6 for Port 0 and
Figure 21-7 for Port 1.
All of the GPIO pins share a single interrupt vector, which
means the firmware will need to read the GPIO ports with
enabled interrupts to determine which pin or pins caused
an interrupt.The GPIO interrupt structure is illustrated in
Figure 21-8.
Note that if one port pin triggered an interrupt, no other port
pins can cause a GPIO interrupt until that port pin has returned to its inactive (non-trigger) state or its corresponding
port interrupt enable bit is cleared. The CY7C637xxC does
not assign interrupt priority to different port pins and the
Port Interrupt Enable Registers are not affected by the interrupt acknowledge process.
1 = Enable
0 = Disable
Bit [5:4]: Capture Timer A and B Interrupts
There are two capture timer interrupts, one for each
associated pin. Each of these interrupts occurs on an enabled
edge of the selected GPIO pin(s). For each pin, rising and/or
falling edge capture interrupts can be in selected. Refer to
Section 19.0. These interrupts are independent of the GPIO
interrupt, described in the next section.
1 = Enable
0 = Disable
Bit 3: SPI Interrupt Enable
The SPI interrupt occurs at the end of each SPI byte transaction, at the final clock edge, as shown in Figure 17-4. After
the interrupt, the received data byte can be read from the SPI
Data Register, and the TCMP control bit will be high
1 = Enable
0 = Disable
Bit 2: 1.024-ms Interrupt Enable
The 1.024-ms interrupts are periodic timer interrupts from
the free-running timer (based on the 6-MHz clock). The
user should disable this interrupt before going into the suspend mode to avoid possible conflicts between servicing
the timer interrupts (128-µs interrupt and 1.024-ms interrupt) first or the suspend request first when waking up.
1 = Enable. Periodic interrupts will be generated approximately every 1.024 ms.
0 = Disable.
Bit 1: 128-µs Interrupt Enable
The 128-µs interrupt is another source of timer interrupt
from the free-running timer. The user should disable both
timer interrupts (128-µs and 1.024-ms) before going into
the suspend mode to avoid possible conflicts between servicing the timer interrupts first or the suspend request first
when waking up.
1 = Enable. Periodic interrupts will be generated approximately every 128 µs.
0 = Disable.
Bit 0: USB Bus Reset - PS/2 Interrupt Enable
The function of this interrupt is selectable between detection of either a USB bus reset condition, or PS/2 activity.
The selection is made with the USB-PS/2 Interrupt Mode
bit in the USB Status and Control Register (Figure 13-1). In
either case, the interrupt will occur if the selected condition
exists for 256 µs, and may occur as early as 128 µs.
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A USB bus reset is indicated by a single ended zero (SE0)
on the USB D+ and D– pins. The USB Bus Reset interrupt
occurs when the SE0 condition ends. PS/2 activity is indicated by a continuous LOW on the SDATA pin. The PS/2
interrupt occurs as soon as the long LOW state is detected.
During the entire interval of a USB Bus Reset or PS/2 interrupt event, the USB Device Address register is cleared.
The Bus Reset/PS/2 interrupt may occur 128 µs after the
bus condition is removed.
1 = Enable
0 = Disable
Bit #76543210
Bit NameReservedEP2
Interrupt
Enable
Read/Write ----- R/WR/WR/W
Reset00000000
Figure 21-2. Endpoint Interrupt Enable Register
(Address 0x21)
Bit [7:3]: Reserved.
Bit [2:1]: EP2,1 Interrupt Enable
There are two non-control endpoint (EP2 and EP1) interrupts. If enabled, a non-control endpoint interrupt is generated when:
• The USB host writes valid data to an endpoint FIFO.
However, if the endpoint is in ACK OUT modes, an in-
EP1
Interrupt
Enable
EP0
Interrupt
Enable
terrupt is generated regardless of data packet validity
(i.e., good CRC). Firmware must check for data validity.
• The device SIE sends a NAK or STALL handshake packet to the USB host during the host attempts to read data
from the endpoint (INs).
• The device receives an ACK handshake after a successful read transaction (IN) from the host.
• The device SIE sends a NAK or STALL handshake packet to the USB host during the host attempts to write data
(OUTs) to the endpoint FIFO.
1 = Enable
0 = Disable
Refer to Table 22-1 for more information.
Bit 0: EP0 Interrupt Enable
If enabled, a control endpoint interrupt is generated when:
• The endpoint 0 mode is set to accept a SETUP token.
• After the SIE sends a 0-byte packet in the status stage
of a control transfer.
• The USB host writes valid data to an endpoint FIFO.
However, if the endpoint is in ACK OUT modes, an interrupt is generated regardless of what data is received.
Firmware must check for data validity.
• The device SIE sends a NAK or STALL handshake packet to the USB host during the host attempts to read data
from the endpoint (INs).
• The device SIE sends a NAK or STALL handshake packet to the USB host during the host attempts to write data
(OUTs) to the endpoint FIFO.
Figure 21-4. Port 0 Interrupt Enable Register (Address
0x04)
Bit [7:0]: P0 [7:0] Interrupt Enable
1 = Enables GPIO interrupts from the corresponding input
pin.
0 = Disables GPIO interrupts from the corresponding input
pin.
Bit #76543210
Bit NameP1 Interrupt Enable
Read/WriteWWWWWWWW
Reset00000000
Figure 21-5. Port 1 Interrupt Enable Register
(Address 0x05)
Bit [7:0]: P1 [7:0] Interrupt Enable
1 = Enables GPIO interrupts from the corresponding input
pin.
0 = Disables GPIO interrupts from the corresponding input
pin.
The polarity that triggers an interrupt is controlled independently for each GPIO pin by the GPIO Interrupt Polarity
Registers. Figure 21-6 and Figure 21-7 control the interrupt
polarity of each GPIO pin.
Bit #76543210
Bit NameP0 Interrupt Polarity
Read/WriteWWWWWWWW
Reset00000000
Figure 21-6. Port 0 Interrupt Polarity Register
(Address 0x06)
Bit [7:0]: P0[7:0] Interrupt Polarity
1 = Rising GPIO edge
0 = Falling GPIO edge
Bit #76543210
Bit NameP1 Interrupt Polarity
Read/WriteWWWWWWWW
Reset00000000
Figure 21-7. Port 1 Interrupt Polarity Register
(Address 0x07)
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Bit [7:0]: P1[7:0] Interrupt Polarity
1 = Rising GPIO edge
0 = Falling GPIO edge
Port Bit Interrupt
Polarity Register
GPIO
Pin
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OR Gate
(1 input per
GPIO pin)
M
U
X
GPIO Interrupt
Flip Flop
D
1
CLR
Q
Interrupt
Priority
Encoder
IRQout
Interrupt
Vector
1 = Enable
0 = Disable
IRA
Port Bit Interrupt
Enable Register
1 = Enable
0 = Disable
Global
GPIO Interrupt
Enable
(Bit 6, Register 0x20)
Figure 21-8. GPIO Interrupt Diagram
22.0 USB Mode Tables
The following tables give details on mode setting for the USB
Serial Interface Engine (SIE) for both the control endpoint
(EP0) and non-control endpoints (EP1 and EP2).
Table 22-1. USB Register Mode Encoding for Control and Non-Control Endpoints
Mode EncodingSETUPINOUTComments
Disable 0000IgnoreIgnoreIgnoreIgnore all USB traffic to this endpoint
NAK IN/OUT 0001AcceptNAKNAKOn Control endpoint, after successfully sending an ACK
handshake to a SETUP packet, the SIE forces the
endpoint mode (from modes other than 0000) to 0001.
The mode is also changed by the SIE to 0001 from mode
1011 on issuance of ACK handshake to an OUT.
Status OUT Only0010AcceptSTALLCheckFor Control endpoints
STALL IN/OUT 0011AcceptSTALLSTALL For Control endpoints
Ignore IN/OUT 0100AcceptIgnoreIgnoreFor Control endpoints
Reserved0101IgnoreIgnoreAlways Reserved
Status IN Only0110AcceptTX 0 Byte STALL For Control Endpoints
Reserved0111IgnoreTX CountIgnoreReserved
NAK OUT 1000IgnoreIgnoreNAKIn mode 1001, after sending an ACK handshake to an
OUT, the SIE changes the mode to 1000
This mode is changed by the SIE to mode 1000 on
issuance of ACK handshake to an OUT
issuance of ACK handshake to an OUT
This mode is changed by the SIE to mode 1100 on
issuance of ACK handshake to an IN
issuance of ACK handshake to an IN
ACK OUT(
ACK OUT(STALL
STALL
[3]
=0)
[3]
=1)
1001
1001
Ignore
Ignore
Ignore
Ignore
ACK
STALL
NAK OUT - Status IN1010AcceptTX 0 ByteNAK
ACK OUT - NAK IN1011AcceptNAKACKThis mode is changed by the SIE to mode 0001 on
NAK IN1100IgnoreNAKIgnoreAn ACK from mode 1101 changes the mode to 1100
(STALL
[3]
=0)
[3]
=1)
1101
1101
Ignore
Ignore
TX Count
STALL
Ignore
Ignore
ACK IN
ACK IN(STALL
NAK IN - Status OUT1110AcceptNAKCheckAn ACK from mode 1111 changes the mode to 1110
ACK IN - Status OUT1111AcceptTX CountCheckThis mode is changed by the SIE to mode 1110 on
Note:
3. STALL bit is the bit 7 of the USB Non-Control Device Endpoint Mode registers. Refer to Section 14.3 for more explanation.
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Mode Column:
The 'Mode' column contains the mnemonic names given to the
modes of the endpoint. The mode of the endpoint is determined by the four-bit binaries in the 'Encoding' column as
discussed below. The Status IN and Status OUT modes
represent the status IN or OUT stage of the control transfer.
Encoding Column:
The contents of the 'Encoding' column represent the Mode Bits
[3:0] of the Endpoint Mode Registers (Figure 14-2 and
Figure 14-3). The endpoint modes determine how the SIE
responds to different tokens that the host sends to the
endpoints. For example, if the Mode Bits [3:0] of the Endpoint
0 Mode Register (Figure 14-2) are set to '0001', which is NAK
IN/OUT mode as shown in Table 22-1 above, the SIE of the
part will send an ACK handshake in response to SETUP
tokens and NAK any IN or OUT tokens. For more information
on the functionality of the Serial Interface Engine (SIE), see
Section 13.0.
SETUP, IN, and OUT Columns:
Depending on the mode specified in the 'Encoding' column,
the 'SETUP', 'IN', and 'OUT' columns contain the device SIE's
responses when the endpoint receives SETUP, IN, and OUT
tokens respectively.
A 'Check' in the Out column means that upon receiving an
OUT token the SIE checks to see whether the OUT is of zero
length and has a Data Toggle (Data1/0) of 1. If these conditions are true, the SIE responds with an ACK. If any of the
above conditions is not met, the SIE will respond with either a
STALL or Ignore. Table 22-3 gives a detailed analysis of all
possible cases.
A 'TX Count' entry in the IN column means that the SIE will
transmit the number of bytes specified in the Byte Count Bit
[3:0] of the Endpoint Count Register (Figure 14-4) in response
to any IN token.
A 'TX 0 Byte' entry in the IN column means that the SIE will
transmit a zero byte packet in response to any IN sent to the
endpoint. Sending a 0 byte packet is to complete the status
stage of a control transfer.
An 'Ignore' means that the device sends no handshake tokens.
An 'Accept' means that the SIE will respond with an ACK to a
valid SETUP transaction.
Comments Column:
Some Mode Bits are automatically changed by the SIE in
response to many USB transactions. For example, if the Mode
Bits [3:0] are set to '1111' which is ACK IN-Status OUT mode
as shown in Table 22-1, the SIE will change the endpoint Mode
Bits [3:0] to NAK IN-Status OUT mode (1110) after ACKing a
valid status stage OUT token. The firmware needs to update
the mode for the SIE to respond appropriately. See Table 22-1
for more details on what modes will be changed by the SIE.
Any SETUP packet to an enabled endpoint with mode set to
accept SETUPs will be changed by the SIE to 0001 (NAKing).
Any mode set to accept a SETUP will send an ACK handshake
to a valid SETUP token.
A disabled endpoint will remain disabled until changed by
firmware, and all endpoints reset to the Disabled mode (0000).
Firmware normally enables the endpoint mode after a SetConfiguration request.
The control endpoint has three status bits for identifying the
token type received (SETUP, IN, or OUT), but the endpoint
must be placed in the correct mode to function as such.
Non-control endpoints should not be placed into modes that
accept SETUPs.
Table 22-2. Decode table for Table 22-3: “Details of Modes for Differing Traffic Conditions”
Endpoint Mode
Encoding
3 2 1 0 Token countbufferdvalDTOGDVALCOUNT
Received Token
(SETUP, IN,OUT)
Legend:
Properties of incoming
packet
The validity of the received dataAcknowledge transaction completed
The quality status of the DMA bufferPID Status Bits
Changes to the internal register made by the SIE as a result of
the incoming token
SetupInOutACK3 2 1 0 Response Int
Bit[3:0], Figure 14-4SIE’s Response
Data Valid (Bit 6, Figure 14-4)Endpoint Mode changed
Data 0/1 (Bit 7, Figure 14-4)
(Bit4,Figure 14-2/3)
(Bit[7:5], Figure 14-2)
End Point
Mode
by the SIE.
Interrupt?
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The response of the SIE can be summarized as follows:
1. The SIE will only respond to valid transactions, and will ignore non-valid ones.
2. The SIE will generate an interrupt when a valid transaction
is completed or when the FIFO is corrupted. FIFO
corruption occurs during an OUT or SETUP transaction to
a valid internal address, that ends with a non-valid CRC.
3. An incoming Data packet is valid if the count is <
Endpoint
Size + 2 (includes CRC) and passes all error checking;
4. An IN will be ignored by an OUT configured endpoint and
visa versa.
5. The IN and OUT PID status is updated at the end of a
transaction.
6. The SETUP PID status is updated at the beginning of the
Data packet phase.
7. The entire Endpoint 0 mode register and the Count register
are locked to CPU writes at the end of any transaction to
that endpoint in which an ACK is transferred. These
registers are only unlocked by a CPU read of these
registers, and only if that read happens after the transaction
completes. This represents about a 1-µs window in which
the CPU is locked from register writes to these USB
registers. Normally the firmware should perform a register
read at the beginning of the Endpoint ISRs to unlock and
get the mode register information. The interlock on the
Mode and Count registers ensures that the firmware
recognizes the changes that the SIE might have made
during the previous transaction.
Table 22-3. Details of Modes for Differing Traffic Conditions
Table 22-3. Details of Modes for Differing Traffic Conditions (continued)
110 0 OUTxUCxUCUCUCUCUCUCUCNoChange Ignoreno
110 0 INxUCxUCUCUCUC1UCUCNoChange NAKyes
Reserved
011 1 OutxUCxUCUCUCUCUCUCUCNoChange Ignoreno
011 1 INxUCxUCUCUCUC1UCUCNoChange TXyes
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23.0 Register Summary
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AddressRegister Name Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
0x00 Port 0 DataP0BBBBBBBB00000000
0x01 Port 1 DataP1BBBBBBBB00000000
0x02 Port 2 DataReservedD+(SCLK)
0x0A GPIO Port 0 Mode 0P0[7:0] Mode0WWWWWWWW 00000000
0x0B GPIO Port 0 Mode 1P0[7:0] Mode1WWWWWWWW 00000000
0x0C GPIO Port 1 Mode 0P1[7:0] Mode0WWWWWWWW 00000000
0x0D GPIO Port 1 Mode 1P1[7:0] Mode1WWWWWWWW 00000000
0x04 Port 0 Interrupt EnableP0[7:0] Interrupt EnableWWWWWWWW 00000000
0x05 Port 1 Interrupt EnableP1[7:0] Interrupt EnableWWWWWWWW 00000000
0x06 Port 0 Interrupt PolarityP0[7:0] Interrupt PolarityWWWWWWWW 00000000
0x07 Port 1 Interrupt PolarityP1[7:0] Interrupt PolarityWWWWWWWW 00000000
GPIO CONFIGURATION PORTS 0, 1 AND 2
0xF8 Clock ConfigurationExt. Clock
Clock
Config.
0x10 USB Device AddressDevice
0x12 EP0 ModeSETUP
0x14,
CONFIGURATION
ENDPOINT 0, I AND 2
EP1, EP2 Mode RegisterSTALLReservedACKed
0x16
0x11,
EP0,1, and 2 CounterData 0/1
0x13, and
0x15
Resume
Delay
Address
Enable
ReceivedINReceived
Tog g le
Wake-up Timer Adjust Bit [2:0]Low-voltage
Received
Data ValidReservedByte CountBB--BBBB00000000
Stat e
OUT
D- (SDATA)
Stat e
ACKed
Transaction
Transaction
ReservedP2.1 (Int Clk
Reset
Disable
Device AddressBBBBBBBB00000000
Precision
Clocking
Enable
Mode Only
USB
Internal
Clock
Output
Disable
Mode BitBBBBBBBB00000000
Mode BitB--BBBBB00000000
VREG Pin
Stat e
External
Oscillator
Enable
Read/Write/
Both/
--RR--RR00000000
BBBBBBBB00000000
Default/
Reset
0x1F USB Status and ControlPS/2 Pull-up
SC
USB-
0x20 Global Interrupt EnableWake-up
0x21Endpoint Interrupt EnableReserved EP2
INTERRUPT
0x24 Timer LSBTimer Bit [7:0]RRRRRRRR00000000
0x25Timer (MSB)ReservedTimer Bit [11:8]----RRRR00000000
TIMER
0x60 SPI DataData I/OBBBBBBBB00000000
0x61 SPI Control TCMP TBFComm Mode [1:0] CPOLCPHASCK SelectBBBBBBBB00000000
SPI
0x40 Capture Timer A-Rising,
Data Register
0x41 Capture Timer A-Falling,
Data Register
0x42 Capture Timer B-Rising,
Data Register
0x43 Capture Timer B-Falling,
Data Register
0x44 Capture Timer
CAPTURE TIMER
PROC
SC.
Configuration
0x45 Capture Timer StatusReservedCapture B
0xFF Process Status & ControlIRQ
Enable
Interrupt
Enable
First Edge
Hold
Pending
VREG
Enable
GPIO
Interrupt
Enable
Watc h Do g
Reset
USB
Reset-PS/2
Activity
Interrupt
Mode
Capture
Timer B Intr.
Enable
Prescale Bit [2:0]Capture B
Bus
Interrupt
Event
ReservedUSB Bus
Capture
Timer A Intr.
Enable
Capture A Rising DataRRRRRRRR00000000
Capture A Falling DataRRRRRRRR00000000
Capture B Rising DataRRRRRRRR00000000
Capture B Falling DataRRRRRRRR00000000
LVR /BO R
Reset
Activity
SPI
Interrupt
Enable
Falling Intr
Enable
Falling
Event
SuspendInterrupt
1.024 ms
Interrupt
Enable
Interrupt
Enable
Capture B
Rising Intr
Enable
Capture B
Rising Event
Enable
Sense
D+/D- Forcing BitBBB-BBBB00000000
128 µs
Interrupt
Enable
EP1
Interrupt
Enable
Capture A
Falling Intr
Enable
Capture A
Falling
Event
ReservedRunRBBBBR-BSee
USB Bus
Reset-PS/2
Activity Intr.
Enable
EP0
Interrupt
Enable
Capture A
Rising Intr
Enable
Capture A
Rising Event
BBBBBBBB00000000
-----BBB00000000
BBBBBBBB00000000
----BBBB00000000
Section
20.0
Document #: 38-08022 Rev. *CPage 37 of 49
FOR
FOR
CY7C63722C
CY7C63723C
CY7C63743C
24.0 Absolute Maximum Ratings
Storage Temperature ..........................................................................................................................................–65°C to +150°C
Ambient Temperature with Power Applied...............................................................................................................–0°C to +70°C
Supply Voltage on V
DC Input Voltage........................................................................................................................................... –0.5V to +V
DC Voltage Applied to Outputs in High Z State............................................................................................ –0.5V to + VCC+0.5V
Maximum Total Sink Output Current into Port 0 and 1 and Pins.......................................................................................... 70 mA
Maximum Total Source Output Current into Port 0 and 1 and Pins ..................................................................................... 30 mA
Maximum On-chip Power Dissipation on any GPIO Pin ......................................................................................................50 mW
Power Dissipation ..............................................................................................................................................................300 mW
Static Discharge Voltage .................................................................................................................................................. > 2000V
Latch-up Current ........................................................................................................................................................... > 200 mA
25.0 DC Characteristics FOSC = 6 MHz; Operating Temperature = 0 to 70°C
V
CC1
V
CC2
I
CC1
I
CC2
I
SB1
I
SB2
V
PP
T
RSNTR
I
IL
I
SNK
I
SRC
Operating VoltageNote 4V
Operating VoltageNote 44.355.25V
VCC Operating Supply Current – Internal
Oscillator Mode
Typica l I
VCC Operating Supply Current – External
Oscillator Mode
Typica l I
Standby Current – No Wake-up OscOscillator off, D– > 2.7V25µA
Standby Current – With Wake-up OscOscillator off, D– > 2.7V75µA
Max ISS GPIO Sink CurrentCumulative across all ports
Max ICC GPIO Source CurrentCumulative across all ports
Relative to VSS..................................................................................................................–0.5V to +7.0V
CC
CC
ParameterConditionsMin.Max.Unit
General
5.5V
20mA
17mA
70mA
30mA
CC1
CC2
= 16 mA
= 13 mA
LVR
V
= 5.5V, no GPIO loading
CC
[5]
[5]
= 5.0V. T = Room Temperature
V
CC
V
= 5.5V, no GPIO loading
CC
V
= 5.0V. T = Room Temperature
CC
[6]
[6]
+0.5V
Low-Voltage and Power-on Reset
V
LVR
t
VCCS
Low-Voltage Reset Trip VoltageVCC below V
for >100 ns
LVR
VCC Power-on Slew Timelinear ramp: 0 to 4V
[8]
[7]
3.54.0V
100ms
USB Interface
V
REG
C
REG
V
OHU
Notes:
4. Full functionality is guaranteed in V
5. Bench measurements taken under nominal operating conditions. Spec cannot be guaranteed at final test.
6. Total current cumulative across all Port pins, limited to minimize Power and Ground-Drop noise effects.
7. LVR is automatically disabled during suspend mode.
8. LVR will re-occur whenever V
9. V
output is not regulated, and should not be used as a general source of regulated voltage in that case. During receive of USB data, the VREG output drops
when D– is LOW due to internal series resistance of approximately 200Ω at the VREG pin.
10. In suspend mode, V
VREG Regulator Output Voltage Load = RPU +R
Capacitance on VREG PinExternal cap not required300pF
Static Output High, drivenRPD to Gnd
range, except USB transmitter specifications and GPIO output currents are guaranteed for V
CC1
drops below V
specified for regulator enabled, idle conditions (i.e., no USB traffic), with load resistors listed. During USB transmits from the internal SIE, the VREG
REG
CC
is only valid if RPU is connected from D– to VREG pin, and RPD is connected from D– to ground.
REG
. In suspend or with LVR disabled, BOR occurs whenever VCC drops below approximately 2.5V.
LVR
[9, 10]
PD
[4]
3.03.6V
2.83.6V
range.
CC2
Document #: 38-08022 Rev. *CPage 38 of 49
FOR
FOR
25.0 DC Characteristics FOSC = 6 MHz; Operating Temperature = 0 to 70°C (continued)
ParameterConditionsMin.Max.Unit
V
V
V
V
V
C
I
R
R
V
R
OLU
OHZ
DI
CM
SE
IN
LO
PU
PD
OLP
PS2
Static Output LowWith RPU to VREG pin0.3V
Static Output High, idle or suspendR
connected D– to Gnd, RPU
PD
connected D– to VREG pin
[4]
Differential Input Sensitivity |(D+)–(D–)|0.2V
Differential Input Common Mode Range0.82.5V
Single Ended Receiver Threshold0.82.0V
Transceiver Capacitance20pF
Hi-Z State Data Line Leakage0 V < Vin<3.3 V (D+ or D– pins)–1010µA
External Bus Pull-up resistance (D–)1.3 kΩ ±2% to V
REG
[11]
External Bus Pull-down resistance15 kΩ ±5% to Gnd14.2515.75 kΩ
PS/2 Interface
Static Output LowIsink = 5 mA, SDATA or SCLK pins0.4V
11. The 200Ω internal resistance at the VREG pin gives a standard USB pull-up using this value. Alternately, a 1.5 kΩ,5%pull-up from D– to an external 3.3V supply
can be used.
Pull-up Resistance824kΩ
Input Threshold Voltage, CMOS modeLow to high edge, Port 0 or 140%60%V
Input Threshold Voltage, CMOS modeHigh to low edge, Port 0 or 135%55%V
Input Hysteresis Voltage, CMOS modeHigh to low edge, Port 0 or 13%10%V
Input Threshold Voltage, TTL modePorts 0, 1, and 20.82.0V
[4]
[4]
[4]
[4]
[4]
0.8
0.4
0.4V
0.4V
V
V
VCC–2V
Output Low Voltage, high drive modeI
Output Low Voltage, medium drive modeI
Output Low Voltage, low drive modeI
= 50 mA, Ports 0 or 1
OL1
I
= 25 mA, Ports 0 or 1
OL1
= 8 mA, Ports 0 or 1
OL2
= 2 mA, Ports 0 or 1
OL3
Output High Voltage, strong drive modePort 0 or 1, IOH = 2 mA
SDATA/SCK Transition Fall TimeCLoad = 150 pF to 600 pF50300ns
SPI TimingSee Figures 26-6 to 26-9
T
SMCK
T
SSCK
Notes:
12. Initially F
13. Wake-up time for Wake-up Adjust Bits cleared to 000b (minimum setting)
14. Tested at 200 pF.
15. Measured at cross-over point of differential data signals.
16. Non-USB Mode refers to driving the D–/SDATA and/or D+/SCLK pins with the Control Bits of the USB Status and Control Register, with Control Bit 2 HIGH.
17. SPI timing specified for capacitive load of 50 pF, with GPIO output mode = 01 (medium low drive, strong high drive).
18. Per the USB 2.0 Specification, Table 7.7, Note 10, the first transition from the Idle state is excluded.
SPI Master Clock RateF
/3; see Figure 17-12MHz
CLK
SPI Slave Clock Rate2.2MHz
= F
ICLK2
until a USB packet is received.
ICLK
[17]
Document #: 38-08022 Rev. *CPage 40 of 49
FOR
FOR
CY7C63722C
CY7C63723C
CY7C63743C
26.0 Switching Characteristics (continued)
ParameterDescriptionConditionsMin.Max.Unit
T
SCKH
T
SCKL
T
MDO
T
MDO1
T
MSU
T
MHD
T
SSU
T
SHD
T
SDO
T
SDO1
T
SSS
T
SSH
SPI Clock High TimeHigh for CPOL = 0, Low for CPOL = 1125ns
SPI Clock Low TimeLow for CPOL = 0, High for CPOL = 1125ns
Master Data Output TimeSCK to data valid–2550ns
Master Data Output Time,
Time before leading SCK edge100ns
First bit with CPHA = 1
Master Input Data Set-up time50ns
Master Input Data Hold time50ns
Slave Input Data Set-up Time50ns
Slave Input Data Hold Time50ns
Slave Data Output TimeSCK to data valid100ns
Slave Data Output Time,
Time after SS LOW to data valid100ns
First bit with CPHA = 1
Slave Select Set-up TimeBefore first SCK edge150ns
Slave Select Hold TimeAfter last SCK edge150ns
CLOCK
V
oh
V
crs
V
ol
D+
D−
T
CYC
T
CH
T
CL
Figure 26-1. Clock Timing
T
R
90%
10%
90%
Figure 26-2. USB Data Signal Timing
T
F
10%
Document #: 38-08022 Rev. *CPage 41 of 49
FOR
FOR
CY7C63722C
CY7C63723C
CY7C63743C
T
PERIOD
Differential
Data Lines
T
PERIOD
Differential
Data Lines
T
Differential
Data Lines
PERIOD
T
JR
T
JR1
Consecutive
Transitions
PERIOD
+ T
JR1
N * T
Paired
Transitions
PERIOD
+ T
JR2
N * T
Figure 26-3. Receiver Jitter Tolerance
Crossover
Crossover
Point Extended
Point
Diff. Data to
N * T
SE0 Skew
+ T
PERIOD
DEOP
Source EOP Width: T
Receiver EOP Width: T
Figure 26-4. Differential to EOP Transition Skew and EOP Width
Table 28-1 below shows the die pad coordinates for the CY7C63722C-XC. The center location of each bond pad is relative to
the bottom left corner of the die which has coordinate (0,0).
Table 28-1. CY7C63722C-XC Probe Pad Coordinates in microns ((0,0) to bond pad centers)
Pad NumberPin Name
(microns)
1P0.0788.952843.15
2P0.1597.452843.15
3P0.2406.002843.15
4P0.3154.952687.95
5P1.0154.952496.45
6P1.2154.952305.05
7P1.4154.952113.60
8P1.6154.951922.05
9Vss154.951730.90
10Vss154.95312.50
11Vpp363.90184.85
12VREG531.70184.85
13XTALIN1066.55184.85
14XTALOUT1210.75184.85
15Vcc1449.75184.85
16D–1662.35184.85
17D+1735.35289.85
18P1.71752.051832.75
19P1.51752.052024.30
20P1.31752.052215.75
21P1.11752.052407.15
22P0.71752.052598.65
23P0.61393.252843.15
24P0.51171.802843.15
25P0.4980.352843.15
X
Y
(microns)
enCoRe is a trademark of Cypress Semiconductor Corporation. All product and company names mentioned in this document
may be the trademarks of their respective holders.