CY7C66013-PVC Cypress Semiconductor Corp, CY7C66013-PVC Datasheet - Page 14

• Manufacturer Part Number: CY7C66013-PVC
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY7C66013-PVC

• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / RoHS Status: Not Compliant

5.2
The accumulator is the general-purpose register for the microcontroller.
5.3
The “X” register is available to the firmware for temporary storage of intermediate results. The microcontroller can perform indexed
operations based on the value in X. Refer to Section 5.6.3 for additional information.
5.4
During a reset, the program stack pointer (PSP) is set to 0x00 and “grows” upward from this address. The program stack pointer
may be set by firmware, using the MOV PSP ,A instruction. The PSP supports interrupt service under hardware control and CALL,
RET, and RETI instructions under firmware control. The PSP is not readable by the firmware.
During an interrupt acknowledge, interrupts are disabled and the 14-bit 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 overall 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 overall effect is
to restore the program counter and flags from the program stack, decrement the program stack pointer by two, and re-enable
interrupts.
The call subroutine (CALL) instruction stores the program counter and flags on the program stack and increments the PSP by two.
The return from subroutine (RET) instruction restores the program counter but not the flags from the program stack and decre-
ments the PSP by two.
5.4.1
The CY7C66112 and CY7C66113 microcontrollers provide 256 bytes of data RAM. In normal usage, the SRAM is partitioned
into four areas: program stack, user variables, data stack, and USB endpoint FIFOs, as shown below:
Notes:
5.5
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 DSP will be reset to 0x00. A PUSH instruction when DSP equals 0x00 will write data at the top of the data
RAM (address 0xFF). This would write data to the memory area reserved for USB endpoint FIFOs. Therefore, the DSP should
be indexed at an appropriate memory location that will not compromise the Program Stack, user-defined memory (variables), or
the USB endpoint FIFOs.
3.
4.
Refer to Section 5.5 for a description of DSP .
Endpoint sizes are fixed by the Endpoint Size Bit (I/O register 0x1F, Bit 7), see Table 18-1 .
8-Bit Accumulator (A)
8-Bit Temporary Register (X)
8-Bit Program Stack Pointer (PSP)
Data Memory Organization
8-Bit Data Stack Pointer (DSP)
8-bit DSP
after reset
8-bit PSP
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PRELIMINARY
Address
0x00
Program Stack begins here and grows upward
The user determines the amount of memory required
User determines the amount of memory required
Data stack can begin here and grow downward (towards 0x00)
User determines the amount of memory required
USB FIFO space for up to two Addresses and five endpoints
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CY7C66011/12/13
CY7C66111/12/13
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