SM59A16U1
8-Bit Micro-controller
64KB with ISP Flash
& 6K+256B RAM embedded
4.3
Program Status Word ( PSW )
Mnemonic: PSW
7
6
CY
AC
CY: Carry flag.
AC: Auxiliary Carry flag for BCD operations.
F0: General purpose Flag 0 available for user.
RS[1:0]: Register bank select, used to select working register bank.
RS[1:0]
Bank Selected
Location
00
Bank 0
00h – 07h
01
Bank 1
08h – 0Fh
10
Bank 2
10h – 17h
11
Bank 3
18h – 1Fh
OV: Overflow flag.
F1: General purpose Flag 1 available for user.
P: Parity flag, affected by hardware to indicate odd/even number of “one” bits in the
Accumulator, i.e. even parity.
4.4
Stack Pointer ( SP )
Address: D0h
0
Reset
P
00h
5
F0
4
RS [1:0]
3
2
OV
1
F1
The stack pointer is a 1-byte register initialized to 07h after reset. This register is incremented before PUSH and CALL
instructions, causing the stack to start from location 08h.
Mnemonic: SP
7
6
Address: 81h
0
Reset
07h
5
4
SP [7:0]
3
2
1
SP[7:0]: The Stack Pointer stores the scratchpad RAM address where the stack begins. In other
words, it always points to the top of the stack.
4.5
Data Pointer( DP )
The data pointer (DPTR) is 2-bytes wide. The lower part is DPL, and the highest is DPH. It can be loaded as a 2-byte
register (e.g. MOV DPTR, #data16) or as two separate registers (e.g. MOV DPL,#data8). It is generally used to access
the external code or data space (e.g. MOVC A, @A+DPTR, @DPTR respectively).
Mnemonic: DPL
7
6
5
4
3
DPL [7:0]
2
1
Address: 82h
0
Reset
00h
DPL[7:0]: Data pointer Low 0
Mnemonic: DPH
7
6
Address: 83h
0
Reset
00h
5
4
3
DPH [7:0]
2
1
DPH [7:0]: Data pointer High 0
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M071
Ver A
SM59A16U1
04/12/2013
- 34 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
