6.6.1 Data .................................................................................................................................................. 9
6.6.2 Direct ................................................................................................................................................ 9
— 6-MHz external ceramic resonator or internal clock mode
— 12-MHz internal CPU clock
— Internal memory
— 96 bytes of RAM
— 3 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
• I/O ports
— Up to 10 versatile General Purpose I/O (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
— XTALIN, XTALOUT and VREG can be configured as additional input pins
• 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 timer (WDT)
• 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 to 70 degrees Celsius
• available in DIE form or 16-pin PDIP
• available in 18-pin SOIC, 18-pin PDIP
• Industry-standard programmer support
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2.0 Functional Overview
2.1enCoRe 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 Cypress enCoRe USB technology is the breakthrough design of a crystalless oscillator. By integrating the oscillator into the 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 family is comprised of 8-bit RISC One Time Programmable (OTP) microcontrollers. 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 features up to 10 general-purpose I/O (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.
The 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 MHz ±1.5%). This clock generator has been optimized to reduce clock-related noise
emissions (EMI), and provides the 6-MHz and 12-MHz clocks that remain internal to the microcontroller. When using the internal
oscillator, XTALIN and XTALOUT can be configured as additional input pins that can be read on port 2. Optionally, an external 6MHz ceramic resonator can be used to provide a higher precision reference if needed.
The is offered with 3 Kbytes of EPROM to minimize cost, and has 96 bytes of data RAM for stack space, user variables, and
USB endpoint FIFOs.
The family includes low-voltage reset logic, a watchdog timer, a vectored interrupt controller, and a 12-bit free-running timer. 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
watchdog timer can be used to ensure the firmware never gets stalled for more than approximately 8 ms.
The microcontroller supports 7 maskable interrupts in the vectored interrupt controller. Interrupt sources include the USB BusReset, the 128-µs and 1.024-ms outputs from the free-running timer, two USB endpoints, an internal wake-up timer and the GPIO
port. The timers bits cause periodic interrupts when enabled. The USB endpoints interrupt after USB transactions complete on
the bus. The GPIO port has 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 event,
and subtracting the two values.
The CY7C63221/31A includes an integrated USB serial interface engine (SIE). The hardware supports one USB device address
with two endpoints. The SIE allows the USB host to communicate with the function integrated into the microcontroller. A 3.3V
regulated output pin provides a pull-up source for the external USB resistor on the D– pin. When using an external voltage
regulator VREG can be configured as an input pin that can be read on port 2 (P2.0).
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.
drops below the operating voltage range. The
CC
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3.0 Logic Block Diagram
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XTALIN/P2.1
XTALIN/P2.1XTALOUT
Internal
Oscillato r
EPROM
3 Kbytes
Brown-Out
Reset
Watch Dog
Timer
Low Voltage
Reset
4.0 Pin Configurations
CY7C63221A
16-pin PDIP
P0.0
P0.1
P0.2
P0.3
V
SS
V
PP
VREG/P2.0
XTALIN/P2.1
1
2
3
4
5
6
7
8
P0.4
16
15
P0.5
P0.6
14
P0.7
13
12
D+/SCLK
11
D–/SDATA
10
V
XTALOUT/P2.2
9
CC
XTALOUT/P2.2
Xtal
Oscillato r
8-bit
RISC
Core
Wake-Up
Timer
Interrupt
Controller
3.3V
Regulator
RAM
96 Bytes
USB
Engine
USB &
PS/2
Xcvr
12-bit
Timer
Port 0
GPIO
VREG/P2.0D+ D-P0.0-P0.7 P1.0-P1.1
(Top View)
CY7C63231A
18-pin SOIC/PDIP
P0.0
1
P0.1
2
P0.2
3
P0.3
4
P1.0
5
6
V
SS
7
V
PP
VREG/P2.0
XTALIN/P2.1
8
9
P0.4
18
17
P0.5
P0.6
16
P0.7
15
P1.1
14
13
D+/SCLK
12
D–/SDATA
V
11
XTALOUT/P2.2
10
CC
CY7C63221A-XC/XWC
DIE
P0.3
P1.0
Vss
Port 1
GPIO
4
5
6
3 P0.2
2 P0.1
7 8 9
Vpp
VREG/P2.0
1 P0.0
18 P0.4
101112
XTALIN/P2.1
XTALOUT/P2.2
17 P0.5
Vcc
16 P0.6
15
14
13
D-/SDATA
P0.7
P1.1
D+/SCLK
5.0 Pin Assignments
CY7C63231A/
CY7C63221A-XC
NameI/O
D–/SDATA,
D+/SCLK
P0[7:0]I/O1, 2, 3, 4,
I/O11
12
13, 14, 15, 16
12
13
1, 2, 3, 4,
15, 16, 17, 18
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 highimpedance input.
P1[1:0]I/ONA5,14IO 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.
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Description16-Pin18-Pin/Pad
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5.0 Pin Assignments (continued)
CY7C63231A/
CY7C63221A-XC
NameI/O
XTALIN/P2.1IN896-MHz ceramic resonator or external clock input, or P2.1 input
XTALOUT/P2.2IN9106-MHz ceramic resonator return pin or internal oscillator output,
or P2.2 input
V
PP
V
CC
VREG/P2.0 78Voltage supply for 1.3-kΩ USB pull-up resistor (3.3V nominal).
V
SS
67Programming voltage supply, ground for normal operation
1011Voltage supply
Also serves as P2.0 input.
56Ground
6.0 Programming Model
Refer to the CYASM Assembler User’s Guide for more details on firmware operation with the microcontrollers.
6.1Program Counter (PC)
The 14-bit program counter (PC) allows access for 3 Kbytes of EPROM using the architecture. The program counter is cleared
during reset, such that the first instruction executed after a reset is at address 0x0000. This 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 6 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.
Note that there are restrictions in using the JMP, CALL, and INDEX instructions across the 4-KB boundary of the program memory.
Refer to the CYASM Assembler User’s Guide for a detailed description.
Description16-Pin18-Pin/Pad
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.
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.
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 re-enable interrupts.
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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.
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. Since there are only 80 bytes of RAM available (except Endpoint FIFOs) the DSP should be set between 0x00
and 0x4Fh. 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
6.6Address Modes
The microcontroller supports 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:
• 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.
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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 5 cycles if jump is taken, 4 cycles if no jump.
MNEMONICOperandOpcodeCycles
HALT 007NOP 204
ADD A,expr data014
ADD A,[expr] direct026INC X x224
ADD A,[X+expr] index037
ADC A,expr data044INC [X+expr] index248
ADC A,[expr] direct056DEC A acc254
ADC A,[X+expr] index067
SUB A,expr data074DEC [expr] direct277
SUB A,[expr] direct086DEC [X+expr] index288
SUB A,[X+expr] index097
SBB A,expr data0A4IOWR expr address2A5
SBB A,[expr] direct0B6POP A2B4
SBB A,[X+expr] index0C7
OR A,expr data0D4PUSH A2D5
OR A,[expr] direct0E6PUSH X2E5
OR A,[X+expr] index0F7
AND A,expr data104SWAP A,DSP305
AND A,[expr] direct116MOV [expr],A direct315
AND A,[X+expr] index127
XOR A,expr data134OR [expr],A direct337
XOR A,[expr] direct146OR [X+expr],A index348
XOR A,[X+expr] index157
CMP A,expr data165AND [X+expr],A index368
CMP A,[expr] direct177XOR [expr],A direct377
CMP A,[X+expr] index188
MOV A,expr data194
MOV A,[expr] direct1A5
MOV A,[X+expr] index1B6
MOV X,expr data1C4ASR 3C4
MOV X,[expr] direct1D5RLC 3D4
reserved 1E
XPAGE 1F4RET 3F8
MOV A,X404
MOV X,A414EI 724
MOV PSP,A604
CALL addr50 - 5F10
JMP addr80-8F5
CALL addr90-9F10
JZ addrA0-AF5 (or 4)
JNZ addrB0-BF5 (or 4)
MNEMONICOperandOpcodeCycles
INC A acc214
INC [expr] direct237
DEC X x264
IORD expr address295
POP X2C4
SWAP A,X2F5
MOV [X+expr],A index326
AND [expr],A direct357
XOR [X+expr],A index388
IOWX [X+expr] index396
CPL 3A4
ASL 3B4
RRC 3E4
DI 704
RETI 738
JC addrC0-CF5 (or 4)
JNC addrD0-DF5 (or 4)
JACC addrE0-EF7
INDEX addrF0-FF14
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8.0 Memory Organization
8.1Program Memory Organization
After resetAddress
14-bit PC0x0000Program execution begins here after a reset.
enCoRe™ USB
CY7C63221/31A
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
0x000CReserved
0x000EReserved
0x0010Reserved
0x0012Reserved
0x0014GPIO interrupt vector
0x0016Wake-up interrupt vector
0x0018Program Memory begins here
0x0BDF3 KB PROM ends here (3K - 32 bytes). See Note 1 below
Figure 8-1. Program Memory Space with Interrupt Vector Table
Note:
1. The upper 32 bytes of the 3K PROM are reserved. Therefore, user’s program must not over-write this space.
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8.2Data Memory Organization
The microcontroller provides 96 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
0x4F
0xF0
0xF8
Top of RAM Memory0xFF
USB FIFO for Address A endpoint 1
USB FIFO for Address A endpoint 0
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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 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 18-
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.
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,
XTALOUT
Port 0 Interrupt Enable0x04WInterrupt enable for pins in Port 019-4
Port 1 Interrupt Enable0x05WInterrupt enable for pins in Port 119-5
Port 0 Interrupt Polarity 0x06WInterrupt polarity for pins in Port 019-6
Port 1 Interrupt Polarity 0x07WInterrupt polarity for pins in Port 119-7
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
USB Device Address0x10R/WUSB Device Address register14-1
Processor Status & Control0xFFR/WProcessor status and control18-1
12-8
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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 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 [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.
Bit 3: Low-voltage Reset Disable
When V
microcontroller enters a partial suspend state for a period of t
drops below V
CC
(see Section 23.0 for the value of V
LVR
) and the Low-voltage Reset circuit is enabled, the
LVR
(see Section 24.0 for the value of t
START
START
). Program
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execution begins from address 0x0000 after this t
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.
1 = Disable internal clock output. XTALOUT pin will drive HIGH.
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.
delay period. This provides time for VCC to stabilize before the part
START
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 Oscillator 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.
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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 18-1). Bits 4 (Low-voltage or Brownout 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.
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
for V
to stabilize. A WDR does not change the clock mode, and there is no delay for VCC stabilization on a WDR. Note that
CC
the External Oscillator Enable (Bit 0, 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.
START
10.1Low-voltage Reset (LVR)
When V
the point where V
of t
START
wait for V
As long as the LVR circuit is enabled, this reset sequence repeats whenever the V
be disabled by firmware by setting the Low-voltage 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 (e.g., by writing ‘0’ to the Low-voltage Reset Disable bit in the Clock Configuration
Register), the chip may enter an unknown state if V
normal operation. If LVR is disabled (e.g., by 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 18-1), is
set to ‘1’ if either a LVR or BOR has occurred.
is first applied to the chip, the internal oscillator is started and the Low-voltage Reset is initially enabled by default. At
CC
(see Section 24.0 for the value of t
to stabilize before it begins executing code from address 0x0000.
CC
has risen above V
CC
(see Section 23.0 for the value of V
LVR
). During this t
START
drops below V
CC
START
), an internal counter starts counting for a period
LVR
time, the microcontroller enters a partial suspend state to
pin voltage drops below V
CC
. Therefore, LVR should be enabled at all times during
LVR
. The LVR can
LVR
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
the device is below an internally defined trip voltage of approximately 2.5V. The BOR re-enables LVR. That is, once V
and trips BOR, the part remains in reset until V
resumes, and the microcontroller starts executing code from address 0x00 after the t
In suspend mode, only the BOR detection is active, giving a reset if V
suspended and code is not executing, this lower reset voltage is safe for retaining the state of all registers and memory. Note that
rises above V
CC
. At that point, the t
LVR
drops below approximately 2.5V. Since the device is
CC
delay occurs before normal operation
START
delay.
START
in suspend mode, LVR is disabled as discussed in Section 10.1.
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CC
CC
drops
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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
(see Figure 10-1) of the last clear. Bit 6 (Watchdog Reset bit) of the Processor Status and Control Register is set to record
WATCH
this event (see Section 18.0 for more details). A Watchdog Timer Reset lasts for typically 2–4 ms after which the microcontroller
begins execution at ROM address 0x0000.
t
WATCH = 10.1 to
WDR
14.6 ms
(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)
11.0 Suspend Mode
The 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 is placed into a low-power state by setting the Suspend bit of the Processor Status and Control Register (Figure 18-1). 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 18-1) 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 19.0).
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
bit interrupts (Figure 19-4 and Figure 19-5) 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 19-1) 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 GPIO
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
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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 19-1) 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.
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
11064 * t
111128 * t
See Section 24.0 for the value of t
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
WAKE
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12.0 General Purpose I/O Ports
Ports 0 and 1 provide up to 10 versatile GPIO pins that can be read or written (the number of pins depends on package type).
V
GPIO
Mode
2
CC
Q3
GPIO
Internal
Data Bus
Data
Out
Register
Q1
Control
14 kΩ
Pin
Port Write
Interrupt
Polarity
Interrupt
Enable
Port Read
Interrupt
Logic
Threshold Select
Q2
To Interrupt
Controller
Figure 12-1. Block Diagram of GPIO Port (one pin shown)
Port 0 is an 8-bit port; Port 1 contains 2 bits, P1.1–P1.0 in the and CY7C63221A-XC parts. Each bit can also be selected as an
interrupt source for the microcontroller.
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.
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.
Bit #76543210
Bit NameP0
Read/WriteR/WR/WR/WR/WR/WR/WR/WR/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
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Bit #76543210
Bit NameReservedP1[1:0]
NotesPins 1:0 in all parts
Read/Write------R/WR/W
Reset00000000
Figure 12-3. Port 1 Data (Address 0x01)
Bit [7:2]: Reserved
Bit [1:0]: P1[1:0]
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 Pin Mode 0 is logic HIGH
0 = Port Pin 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 NameReservedP1[1:0] Mode0
Read/Write------WW
Reset00000000
Figure 12-6. GPIO Port 1 Mode0 Register (Address 0x0C)
Bit [7:2]: Reserved
Bit [1:0]: P1[1:0] Mode 0
1 = Port Pin Mode 0 is logic HIGH
0 = Port Pin Mode 0 is logic LOW
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Bit #76543210
Bit NameReservedP1[1:0] Mode1
Read/Write------WW
Reset00000000
Figure 12-7. GPIO Port 1 Mode1 Register (Address 0x0D)
Bit [7:2]: Reserved
Bit [1:0]: P1[1:0] 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 23.0 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.
Table 12-1. Ports 0 and 1 Output Control Truth Table
Data RegisterMode1Mode0 Output Drive StrengthInput Threshold
0
1Hi-ZTTL
0
1High DriveCMOS
0
1ResistiveCMOS
0
1High DriveCMOS
00
Medium (8 mA) SinkCMOS
01
10
11
Hi-ZCMOS
Low (2 mA) SinkCMOS
High (50 mA) SinkCMOS
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.
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Bit #76543210
Bit NameReservedD+ (SCLK)
Stat e
Read/Write--RR-RRR
Reset00000000
Figure 12-8. Port 2 Data Register (Address 0x02)
Bit [7:6]: Reserved
Bit [5:4]: D+ (SCLK) and D- (SDATA) States
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
Bit 3: Reserved
D– (SDATA)
State
ReservedP2.2
(Internal
Clock Mode
Only)
P2.1
(Internal
Clock Mode
Only)
P2.0
VREG Pin
State
Bit 2: P2.2 (Internal Clock Mode Only)
In the Internal Clock mode, the XTALOUT pin can serve as a general purpose input, and its state can be read at Port 2, Bit 2
(P2.2). See Section 9.1 for more details.
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
Bit 1: P2.1 (Internal Clock Mode Only)
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
Bit 0: P2.0/ VREG Pin State
In PS/2 mode, the VREG
1 = Port Pin is logic HIGH
0 = Port Pin is logic LOW
pin can be used as an input and its state can be read at port P2.0. Section 15.0 for more details.
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.
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13.1USB Enumeration
A typical USB enumeration sequence is shown below. In this description, ‘Firmware’ refers to embedded firmware in the
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 transactions, which may occur from this point.
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 #76543210
Bit NamePS/2 Pull-up
Enable
Read/WriteR/WR/WR/W-R/WR/WR/WR/W
Reset00000000
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
or if the Device Address is enabled (bit 7 of the USB Device Address Register, Figure 14-1).
, but note that the output will be clamped to approximately 1 Volt above V
CC
1 = Enable PS/2 pull-up resistors. The SDATA and SCLK pins are pulled up internally to V
5kΩ (see Section 23.0 for the value of R
0 = Disable PS/2 pull-up resistors.
Bit 6: VREG 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.
VREG
Enable
USB Reset-
PS/2 Activity
ReservedUSB
Bus Activity
Interrupt
Mode
Figure 13-1. USB Status and Control Register (Address 0x1F)
REG
with two resistors of approximately
CC
PS2
).
D+/D- Forcing Bit
if the VREG Enable bit is set,
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.
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 19.0 for more details.
Bit 4: Reserved. Must be written as a ‘0’.
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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 Bit [2:0]Control ActionApplication
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
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.
[2]
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14.0 USB Device
The supports one USB Device Address with two endpoints: EP0 and EP1.
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 #76543210
Bit NameDevice
Address
Enable
Read/WriteR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000
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 19.3 for more
information on the USB Bus Reset - PS/2 interrupt.
Device Address Bit
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.
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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 20-1, 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 20-1. Additional
information on the mode bits can be found in Table 20-2 and Table 20-3. These modes give the firmware total control on how
to respond to different tokens sent to the endpoints from the host.
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 20-1, 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 feature one non-control endpoint, endpoint 1 (EP1). The EP1 Mode Register does not have the locking mechanism of the
EP0 Mode Register. The EP1 Mode Register uses the format shown in Figure 14-3. EP1 uses an 8-byte FIFO at SRAM locations
0xF0–0xF7 as shown in Section 8.2.
Bit #76543210
Bit NameSTALLReservedACKed
Transaction
Read/WriteR/W--R/CR/WR/WR/WR/W
Reset00000000
Figure 14-3. USB Endpoint EP1 Mode Registers (Address 0x14)
Bit 7: STALL
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 20.0 for the available modes.
0 = This bit must be set to LOW for all other modes.
Mode Bit
Bit [6:5]: Reserved. Must be written to zero during register writes.
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.
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Bit [3:0]: Mode Bit [3:0]
The EP1 Mode Bits operate in the same manner as the EP0 Mode Bits (see Section 14.2).
14.4USB Endpoint Counter Registers
There are two 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 #76543210
Bit NameData ToggleData ValidReservedByte Count
Read/WriteR/WR/W--R/WR/WR/WR/W
Reset00000000
Figure 14-4. Endpoint 0 and 1 Counter Registers (Addresses 0x11 and 0x13)
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 20-3 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
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.
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 VREG 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
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 VREG
used as an input and its state can be read at port P2.0. Refer to Figure 12-8 for the Port 2 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
with an internal 6.2-kΩ resistor. This holds the proper VOH state in suspend mode.
CC
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 VREG
pin is effectively disconnected when the 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.
(see Section 23.0).
PU
pin can be
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16.0 PS/2 Operation
The 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
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 19.3 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 VREG pin can be placed into a high-impedance state, 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.
. (Disable USB by clearing the Address Enable bit of the USB Device
CC
Port 2.0
VREG Enable
3.3V
Regulator
V
CC
PS/2 Pull-up
Enable
5 kΩ
USB - PS/2
Driver
Port 2.5
Port 2.4
Figure 16-1. Diagram of USB - PS/2 System Connections
200Ω
5 kΩ
On-chipOff-chip
VREG
1.3 kΩ
D+/SCLK
D–/SDATA
17.0 12-bit Free-running Timer
The 12-bit timer operates with a 1-µs tick, provides two interrupts (128µs and 1.024ms) and allows the firmware to directly time
events that are up to 4 ms in duration. The lower 8 bits of the timer can be read directly by the firmware. Reading the lower 8 bits
latches the upper 4 bits into a temporary register. When the firmware reads the upper 4 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.
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Bit #76543210
Bit NameTimer [7:0]
Read/WriteRRRRRRRR
Reset00000000
Figure 17-1. Timer LSB Register (Address 0x24)
Bit [7:0]: Timer lower 8 bits
Bit #76543210
Bit NameReservedTimer [11:8]
Read/Write----RRRR
Reset00000000
Figure 17-2. Timer MSB Register (Address 0x25)
Bit [7:4]: Reserved
Bit [3:0]: Timer upper 4 bits
1.024-ms interrupt
µs interrupt
128-
10978
6432
5
1011
1 MHz clock
L1L0L2L3
D3D2D1D0D7D6D5D4D3D2D1D0
To Timer Registers
8
Figure 17-3. Timer Block Diagram
18.0 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
ReservedRun
Figure 18-1. Processor Status and Control Register (Address 0xFF)
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 19-1 and Figure 19-2) 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.
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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
a watchdog reset can occur with a 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 19.3. 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 pit last cleared.
(see Section 24.0 for the value of t
WATCH
). This bit is cleared by an LVR/BOR. Note that
WATCH
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 that 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 19-1) and USB Endpoint Interrupt Enable Register (Figure 19-2). 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
start-up (explained in Section 10.1), a Watchdog Reset will also occur. When a WDR occurs during the power-up suspend interval,
ms partial suspend at
START
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 Watch Dog Reset, the Processor Status and Control Register is set to 01XX0001, which indicates a Watch Dog Reset
(bit 4 set) has occurred and no interrupts are pending (bit 7 clear).
19.0 Interrupts
Interrupts can be generated by the GPIO lines, the internal free-running timer, 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 19-3 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 19.1). 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 and 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).
19.1Interrupt Vectors
The Interrupt Vectors supported by the device are listed in Tab le 19 -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
2 bytes to allow for a 2-byte JMP instruction to the appropriate Interrupt Service Routine (ISR).
Table 19-1. Interrupt Vector Assignments
Interrupt Vector NumberROM AddressFunction
not applicable0x0000Execution after Reset begins here.
10x0002USB Bus Reset or PS/2 Activity interrupt
20x0004128-µs timer interrupt
30x00061.024-ms timer interrupt
40x0008USB Endpoint 0 interrupt
50x000AUSB Endpoint 1 interrupt
60x000CReserved
70x000EReserved
80x0010Reserved
90x0012Reserved
100x0014GPIO interrupt
110x0016Wake-up Timer interrupt
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19.2Interrupt 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.
19.3Interrupt Sources
The following sections provide details on the different types of interrupt sources.
Bit #76543210
Bit NameWake-up
Interrupt
Enable
Read/WriteR/WR/W---R/WR/WR/W
Reset00000000
GPIO
Interrupt
Enable
Figure 19-1. Global Interrupt Enable Register (Address 0x20)
Reserved1.024-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 19-4 for Port 0 and Figure 19-5 for Port 1. In addition to enabling the desired individual pins for
interrupt, the main GPIO interrupt must be enabled, as explained in Section 19.0.
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 19-6 for Port 0 and Figure 19-7 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 19-8.
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 CY7C63221/31A 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 [5:3]: Reserved
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.
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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.
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 128µs after the bus condition is removed.
The non-control endpoint interrupt (EP1) is generated when:
• 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 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 20-1 for more information.
Bit 0: EP0 Interrupt Enable
If enabled, the 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 19-4. 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 NameReservedP1[1:0] Interrupt Enable
Read/Write------WW
Reset00000000
Figure 19-5. 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.
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The polarity that triggers an interrupt is controlled independently for each GPIO pin by the GPIO Interrupt Polarity Registers.
Figure 19-6 and Figure 19-7 control the interrupt polarity of each GPIO pin.
Bit #76543210
Bit NameP0 Interrupt Polarity
Read/WriteWWWWWWWW
Reset00000000
Figure 19-6. 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 NameReservedP1[1:0] Interrupt Polarity
Read/Write------WW
Reset00000000
Figure 19-7. Port 1 Interrupt Polarity Register (Address 0x07)
Bit [7:0]: P1[7:0] Interrupt Polarity
1 = Rising GPIO edge
0 = Falling GPIO edge
Port Bit Interrupt
Polarity Register
GPIO
Pin
1 = Enable
0 = Disable
IRA
Port Bit Interrupt
Enable Register
1
Global
Enable
GPIO Interrupt
Flip Flop
D
Q
CLR
Interrupt
Priority
Encoder
IRQout
Interrupt
Vector
OR Gate
(1 input per
GPIO pin)
M
U
X
1 = Enable
0 = Disable
GPIO Interrupt
(Bit 6, Register 0x20)
Figure 19-8. GPIO Interrupt Diagram
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20.0 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 endpoint (EP1).
Table 20-1. USB Register Mode Encoding for Control and Non-Control Endpoint
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 0011AcceptSTALLSTALLFor Control endpoints
Ignore IN/OUT 0100AcceptIgnoreIgnoreFor Control endpoints
Reserved0101IgnoreIgnoreAlwaysReserved
Status IN Only0110AcceptTX 0 ByteSTALLFor Control Endpoints
Reserved0111IgnoreTX CountIgnoreReserved
NAK OUT 1000IgnoreIgnoreNAKIn mode 1001, after sending an ACK handshake to an
OUT, the SIE changes the mode to 1000
ACK OUT(
ACK OUT(STALL
NAK OUT - Status IN1010AcceptTX 0 ByteNAK
ACK OUT - NAK IN1011AcceptNAKACKThis mode is changed by the SIE to mode 0001 on
NAK IN110 0IgnoreNAKIgnoreAn ACK from mode 1101 changes the mode to 1100
ACK IN
(STALL
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.
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 4 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.
STALL
[3]
[3]
[3]
[3]
=0)
=1)
= 0)
= 1)
1001
1001
1101
1101
Ignore
Ignore
Ignore
Ignore
Ignore
Ignore
TX Count
STALL
ACK
STALL
Ignore
Ignore
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
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 20-1 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 20-3 gives 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.
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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 Tab le 20 -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 20-1 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 endpoint should not be placed into modes that accept SETUPs.
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Table 20-2. Decode table for Table 20-3: “Details of Modes for Differing Traffic Conditions”
Endpoint Mode
Encoding
3 2 1 0Token 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?
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.
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Table 20-3. Details of Modes for Differing Traffic Conditions
0x25Timer (MSB)ReservedTimer Bit [11:8]----RRRR00000000
TIMER
0xFFProcess Status & ControlIRQ
SC.
PROC
Interrupt
Enable
Pending
GPIO
Interrupt
Enable
Watch Dog
Reset
Bus
Interrupt
Event
Reserved1.024 ms
LVR /BO R
Reset
SuspendInterrupt
Interrupt
Enable
Enable
Sense
128 µs
Interrupt
Enable
Interrupt
Enable
ReservedRunRBBBBR-BSee
USB Bus
Reset-PS/2
Activity Intr.
Enable
EP0
Interrupt
Enable
BB---BBB00000000
------BB00000000
Section
18.0
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22.0 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
23.0 DC Characteristics
F
= 6 MHz; Operating Temperature = 0 to 70°C
OSC
V
CC1
V
CC2
I
CC1
I
CC2
I
SB1
I
SB2
V
PP
T
RSNTR
I
IL
I
SNK
I
SRC
V
LVR
t
VCCS
V
REG
C
REG
V
OHU
V
OLU
V
OHZ
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.
VCC Operating Supply Current - External
Oscillator Mode.
Typical I
Standby Current - No Wake-up Osc25µAOscillator off, D– > 2.7V
Standby Current - With Wake-up Osc75µAOscillator off, D– > 2.7V
Programming Voltage (disabled)–0.40.4V
Resonator Start-up Interval256µsVCC = 5.0V, ceramic resonator
Input Leakage Current1µAAny I/O pin
Max ISS GPIO Sink Current70mACumulative across all ports
Max ICC GPIO Source Current30mACumulative across all ports
Low-voltage Reset Trip Voltage3.54.0VVCC below V
VCC Power-on Slew Time100mslinear ramp: 0 to 4V
VREG Regulator Output Voltage 3.03.6VLoad = RPU +R
Capacitance on VREG Pin300pFExternal cap not required
Static Output High, driven2.83.6VRPD to Gnd
Static Output Low0.3VWith RPU to VREG pin
Static Output High, idle or suspend2.73.6VR
specified for regulator enabled, idle conditions (i.e., no USB traffic), with load resistors listed. During USB transmits from the internal SIE, the VREG
RG
relative to VSS....................................................................................................................–0.5V to +7.0V
CC
ParameterMinMaxUnitsConditions
General
5.5VNote 4
20mAV
17mAV
CC
V
CC
CC
V
CC
= 5.5V, no GPIO loading
= 5.0V. T = Room Temperature
= 5.5V, no GPIO loading
= 5.0V. T = Room Temperature
CC1
CC2
= 16 mA
= 13 mA
LVR
[5]
[5]
Low-voltage and Power-on Reset
for >100 ns
LVR
[8]
USB Interface
[9, 10]
PD
[4]
connected D– to Gnd, RPU connected
PD
D– to VREG pin
range, except USB transmitter specifications and GPIO output currents are guaranteed for V
CC1
drops below V
CC
is only valid if RPU is connected from D– to VREG pin, and RPD is connected from D– to ground
RG
. In suspend or with LVR disabled, BOR occurs whenever VCC drops below approximately 2.5V.
LVR
[4]
range.
CC2
+0.5V
CC
[6]
[6]
[7]
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ParameterMinMaxUnitsConditions
V
DI
V
CM
V
SE
C
IN
I
LO
R
PU
R
PD
V
OLP
R
PS2
R
UP
V
ICR
V
ICF
V
HC
V
ITTL
V
OL1A
V
OL1B
V
OL2
V
OL3
V
OH
R
XIN
Note:
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.
Differential Input Sensitivity 0.2V|(D+)–(D–)|
Differential Input Common Mode Range0.82.5V
Single Ended Receiver Threshold0.82.0V
Transceiver Capacitance20pF
Hi-Z State Data Line Leakage–1010µA0 V < Vin<3.3 V (D+ or D– pins)
External Bus Pull-up resistance (D–)1.2741.326 kΩ1.3 kΩ ±2% to VREG
[11]
External Bus Pull-down resistance14.2515.75 kΩ15 kΩ ±5% to Gnd
SDATA / SCK Transition Fall Time50300nsCLoad = 150 pF to 600 pF
[4]
)
[4]
)
[4]
)
[4]
)
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. Per the USB 2.0 Specification, Table 7.7, Note 10, the first transition from the Idle state is excluded.
ICLK2=FICLK
until a USB packet is received.
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.
T
CYC
T
CH
CLOCK
T
CL
Figure 24-1. Clock Timing
T
PERIOD
Differential
Data Lines
90%
T
F
10%
T
D+
V
oh
V
crs
V
ol
D−
R
90%
10%
Figure 24-2. USB Data Signal Timing
T
JR
Consecutive
Transitions
N * T
PERIOD
+ T
JR1
Transitions
N * T
Paired
PERIOD
+ T
T
JR1
JR2
T
JR2
Figure 24-3. Receiver Jitter Tolerance
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T
PERIOD
Differential
Data Lines
T
Differential
Data Lines
PERIOD
FOR
FOR
CY7C63221/31A
Crossover
Crossover
Point
Diff. Data to
SE0 Skew
PERIOD
+ T
DEOP
N * T
Figure 24-4. Differential to EOP Transition Skew and EOP Width
CY7C63221A-XWC3 KB-18-Pad DIE Form Lead-freeCommercial
EPROM
Size
26.0 Package Diagrams
Package
NamePackage Type
P116-Pin (300-Mil) PDIP Lead-freeCommercial
P116-Pin (300-Mil) PDIPCommercial
S118-Pin Small Outline Package Lead-freeCommercial
S118-Pin Small Outline PackageCommercial
P318-Pin (300-Mil) PDIPCommercial
-18-Pad DIE FormCommercial
16-Lead (300-Mil) Molded DIP P1
Operating
Range
51-85009-A
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18-Lead (300-Mil) Molded SOIC S1
enCoRe™ USB
CY7C63221/31A
Die Step: 2031.0 x 2279.0 microns
Pad Size: 80 x 80 microns
18-Lead (300-Mil) Molded DIP P3
DIE FORM
Cypress Logo
3
2
1
17
18
(0,0)
X
16
15
14
13
11
12
10
4
5
Y
6
7 8 9
51-85023-A
51-85010-A
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enCoRe™ USB
CY7C63221/31A
Table 26-1 below shows the die pad coordinates for the CY7C63221A-XC. The center location of each bond pad is relative to the
center of the die which has coordinate (0,0) as shown above.
Table 26-1. CY7C63221A-XC Probe Pad Coordinates in microns ((0,0) to bond pad centers)
Pad NumberPin Name
1P0.0–351.75995.00
2P0.1–543.20995.00
3P0.2–734.65995.00
4P0.3–861.05779.25
5P1.0–861.05587.80
6Vss–861.05–949.65
7Vpp–468.20–968.10
8VREG–300.40–968.10
9XTALIN63.30–968.10
10XTALOUT207.50–968.10
11Vcc594.60–968.10
12D–771.35–968.10
13D+844.05–863.10
14P1.1861.05581.95
15P0.7861.05773.95
16P0.6720.15995.00
17P0.5528.70995.00
18P0.4337.25995.00
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.