C2510Fx / CC2511Fx
flag for BCD operations, Register Select bits,
Overflow flag, and Parity flag. Two bits in PSW
are uncommitted and can be used as user-
defined status flags.
PSW (0xD0) – Program Status Word
Bit
Name
Reset
R/W
Description
7
CY
0
R/W
Carry flag. Set to 1 when the last arithmetic operation resulted in a carry
(during addition) or borrow (during subtraction), otherwise cleared to 0 by all
arithmetic operations.
6
AC
0
R/W
Auxiliary carry flag for BCD operations. Set to 1 when the last arithmetic
operation resulted in a carry into (during addition) or borrow from (during
subtraction) the high order nibble, otherwise cleared to 0 by all arithmetic
operations.
5
F0
0
R/W
R/W
User-defined, bit-addressable
4:3
RS[1:0]
00
Register bank select bits. Selects which set of R7- R0registers to use from
four possible register banks in DATA space.
00
01
10
11
Bank 0, 0x00 – 0x07
Bank 1, 0x08 – 0x0F
Bank 2, 0x10 – 0x17
Bank 3, 0x18 – 0x1F
2
OV
0
R/W
Overflow flag, set by arithmetic operations. Set to 1 when the last arithmetic
operation resulted in a carry (addition), borrow (subtraction), or overflow
(multiply or divide). Otherwise, the bit is cleared to 0 by all arithmetic
operations.
1
0
F1
P
0
0
R/W
R/W
User-defined, bit-addressable
Parity flag, parity of accumulator set by hardware to 1 if it contains an odd
number of 1’s, otherwise it is cleared to 0
11.3.4 Accumulator
data transfer and other instructions. The
mnemonic for the accumulator (in instructions
involving the accumulator) refers to A instead
of ACC.
ACC is the accumulator. This is the source
and destination of most arithmetic instructions,
ACC (0xE0) – Accumulator
Bit
Name
Reset
R/W
Description
7:0
ACC[7:0]
0x00
R/W
Accumulator
11.3.5 B Register
purposes it may be used as a scratch-pad
register to hold temporary data.
The B register is used as the second 8-bit
argument during execution of multiply and
divide instructions. When not used for these
B (0xF0) – B Register
Bit
Name
Reset
R/W
Description
7:0
B[7:0]
0x00
R/W
B register. Used in MUL and DIV instructions.
11.3.6 Stack Pointer
copies the byte into the stack. The Stack
Pointer is initialized to 0x07 after a reset and it
is incremented once to start from location
0x08, which is the first register (R0) of the
The stack resides in DATA memory space and
grows upwards. The PUSH instruction first
increments the Stack Pointer (SP) and then
SWRS055D
Page 53 of 243
TAOS [ TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS ]
