
Preliminary W79E225A/227A Data Sheet
Publication Release Date: December 14, 2007
- 56 -
Revision A2.0
BIT
NAME
FUNCTION
7
CY
Carry flag. Set for an arithmetic operation which results in a carry being
generated from the ALU. It is also used as the accumulator for the bit operations.
Auxiliary carry: Set when the previous operation resulted in a carry (during
addition) or a borrow (during subtraction) from the high order nibble.
User flag 0. A general purpose flag that can be set or cleared by the by software.
Register bank selects bits:
RS1 RS2 Register Bank
Address
0
0
0
00-07h
0
1
1
08-0Fh
1
0
2
10-17h
1
1
3
18-1Fh
Overflow flag. Set when a carry was generated from the seventh bit but not from
the 8th bit as a result of the previous operation or vice-versa.
User Flag 1. General purpose flag that can be set or cleared by the user by
software.
Parity flag. Set/cleared by hardware to indicate odd/even number of 1's in the
accumulator.
6
5
AC
F0
4-3
RS.1-0
2
OV
1
F1
0
P
PWMP COUNTER HIGH BITS REGISTER
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
PWMP.11 PWMP.10 PWMP.9
PWMP.8
Mnemonic: PWMPH
Address: D1h
BIT
7-4
3-0
NAME
FUNCTION
-
PWMP.11~PWMP.8 PWM Counter Register bits 11~8.
Reserved.
PWM 0 HIGH BITS REGISTER
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
PWM0.11
PWM0.10
PWM0.9
PWM0.8
Mnemonic: PWM0H
Address: D2h
BIT
NAME
FUNCTION
7~4 -
Reserved.
3~0 PWM0.11
~PWM0.8
The PWM 0 Register bit 11~8.
NVM DATA
Bit:
7
6
5
4
3
2
1
0
NVMDAT.7 NVMDAT.6 NVMDAT.5 NVMDAT.4 NVMDAT.3 NVMDAT.2 NVMDAT.1 NVMDAT.0
Mnemonic: NVMDAT
Address: D3h