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CY7C601xx

CY7C602xx

Document 38-16016 Rev. *C Page 8 of 62

The Stack Pointer Register (CPU_SP) holds the address of the

current top-of-stack in the data memory space. It is affected by

the PUSH, POP, LCALL, CALL, RETI, and RET instructions,

which manage the software stack. It can also be affected by

the SWAP and ADD instructions.

The Flag Register (CPU_F) has three status bits: Zero Flag bit

[1]; Carry Flag bit [2]; Supervisory State bit [3]. The Global

Interrupt Enable bit [0] is used to globally enable or disable

interrupts. The user cannot manipulate the Supervisory State

status bit [3]. The flags are affected by arithmetic, logic, and

shift operations. The manner in which each flag is changed is

dependent upon the instruction being executed (i.e., AND,

OR, XOR). See Table 19.

CPU Registers

Flags Register

The Flags Register can only be set or reset with logical

instruction.

Accumulator Register

Table 3. CPU Flags Register (CPU_F) [R/W]

Bit # 7 6 5 4 3 2 1 0

Field Reserved XIO Super Carry Zero Global IE

Read/Write – – – R/W R RW RW RW

Default 00000010

Bit [7:5]: Reserved

Bit 4: XIO

Set by the user to select between the register banks.

0 = Bank 0

1 = Bank 1

Bit 3: Super

Indicates whether the CPU is executing user code or Supervisor Code. (This code cannot be accessed directly by the user.)

0 = User Code

1 = Supervisor Code

Bit 2: Carry

Set by CPU to indicate whether there has been a carry in the previous logical/arithmetic operation.

0 = No Carry

1 = Carry

Bit 1: Zero

Set by CPU to indicate whether there has been a zero result in the previous logical/arithmetic operation.

0 = Not Equal to Zero

1 = Equal to Zero

Bit 0: Global IE

Determines whether all interrupts are enabled or disabled.

0 = Disabled

1 = Enabled

Note: This register is readable with explicit address 0xF7. The OR F, expr and AND F, expr must be used to set and clear the

CPU_F bits.

Table 4. CPU Accumulator Register (CPU_A)

Bit # 7 6 5 4 3 2 1 0

Field CPU Accumulator [7:0]

Read/Write ––––––––

Default 00000000

Bit [7:0]: CPU Accumulator [7:0]

8-bit data value holds the result of any logical/arithmetic instruction that uses a source addressing mode.

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