SM5958
8-Bit Micro-controller
32KB with ISP Flash
& 1KB RAM embedded
4. CPU Engine
The SM5958 engine is composed of four components:
(1)
(2)
(3)
(4)
Control unit
Arithmetic – logic unit
Memory control unit
RAM and SFR control unit
The SM5958 engine allows to fetch instruction from program memory and to execute using RAM or SFR. The
following chapter describes the main engine register.
Mnemonic
Description
Accumulator
Dir.
Bit 7
Bit 6
8051 Core
E0h ACC.7 ACC.6 ACC.5 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
ACC
B
00H
00H
B register
F0h
B.7
B.6
B.5
B.4
B.3
B.2
B.1
B.0
Program status
word
PSW
D0h
CY
AC
F0
RS[1:0]
OV
PSW.1
P
00H
SP
DPL
DPH
Stack Pointer
Data pointer low
Data pointer high
81h
82h
83h
SP[7:0]
DPL[7:0]
DPH[7:0]
07H
00H
00H
4.1 Accumulator
ACC is the Accumulator register. Most instructions use the accumulator to store the operand.
Mnemonic: ACC
Address: E0h
Reset
00h
7
6
5
4
3
2
1
0
ACC.7 ACC.6 ACC05 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0
ACC[7:0]: The A (or ACC) register is the standard 8052 accumulator.
4.2 B Register
The B register is used during multiply and divide instructions. It can also be used as a scratch pad register to store
temporary data.
Mnemonic: B
Address: F0h
7
B.7
6
B.6
5
B.5
4
B.4
3
B.3
2
B.2
1
B.1
0
B.0
Reset
00h
B[7:0]: The B register is the standard 8052 register that serves as a second accumulator.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M089
Ver A SM5958 3/19/2014
- 22 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
