Cpu registers, 1 flags register – Cypress enCoRe CY7C63310 User Manual
Page 8
CY7C63310, CY7C638xx
Document 38-08035 Rev. *K
Page 8 of 83
7. CPU Registers
The CPU registers in enCoRe II devices are in two banks with 256 registers in each bank. Bit[4]/XIO bit in the CPU Flags register
must be set/cleared to select between the two register banks
7.1 Flags Register
The Flags Register is set or reset only with logical instruction.
Table 7-1. 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
0
0
0
0
0
0
1
0
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 the 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 the 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
CPU_F register is only readable with the explicit register address 0xF7. The OR F, expr and AND F, expr instructions must
be used to set and clear the CPU_F bits.
Table 7-2. CPU Accumulator Register (CPU_A)
Bit #
7
6
5
4
3
2
1
0
Field
CPU Accumulator [7:0]
Read/Write
–
–
–
–
–
–
–
–
Default
0
0
0
0
0
0
0
0
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