W83L951DG Datasheet, PDF (36/112 Pages) Winbond – Mobile Keyboard and Embedded Controller

W83L951DG/W83L951FG
6.1.1 Register Description
6.1.1.1 Program Status Word Register (PSW) (Default Value: 0000_0000)
Bit7: Carry Flag (CY):
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.
Bit6: Auxiliary Carry (AC):
Set when the previous operation resulted in a carry (during addition) or borrow (during subtraction)
from the high order nibble.
Bit5: User Flag 0 (F0):
General-purpose flag can be set or cleared by the user by software.
Bit4~3: Register bank selects bits (RS1, RS0):
RS1 RS0 Register bank
000
011
102
113
Bit2: Overflow Flag (OV):
Address Range
00-07h
08-0Fh
10-17h
18-1Fh
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.
Bit1: User Flag 1 (F1):
General-purpose flag that can be set or cleared by the user by software
Bit0: Parity flag (P):
Set/cleared by hardware to indicate odd/even number of 1's in the accumulator.
Please refer to MCS-8051 define in detail.
6.1.1.2 Accumulator Register (ACC) (Default Value: 0000_0000)
Bit7~0: Accumulator (A)
The A or ACC register is the standard 8032 accumulator. Please refer to MCS-8051 define in detail.
6.1.1.3 B Register (B) (Default Value: 0000_0000)
Bit7~0: B
The B register is the standard 8032 accumulator. Please refer to MCS-8051 define in detail.
6.1.1.4 Stack Pointer Register (SP) (Default Value: 0000_0111)
Bit7~0: Stack Pointer
The Stack Pointer stores the Scratch-pad RAM address where the stack begins. In other words it
always points to the top of the stack. Note: The address range is 00h~FFh.
Please refer to MCS-8051 define in detail.
- 32 -