C541U_99 Datasheet, PDF (20/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

Fundamental Structure
C541U
OSC
(XTAL2)
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6
P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2
ALE
Read
Opcode
Read Next
Opcode (Discard)
S1 S2 S3 S4 S5 S6
(a) 1-Byte, 1-Cycle Instruction, e. g. INC A
Read Next
Opcode Again
Read
Opcode
Read 2nd
Byte
Read Next
Opcode
S1 S2 S3 S4 S5 S6
(b) 2-Byte, 1-Cycle Instruction, e. g. ADD A #DATA
Read
Opcode
Read Next Opcode (Discard)
Read Next
Opcode Again
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6
(c) 1-Byte, 2-Cycle Instruction, e. g. INC DPTR
Read
Opcode
(MOVX)
Read Next
Opcode
(Discard)
Read Next Opcode Again
No Fetch
No ALE
No Fetch
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6
(d) MOVX (1-Byte, 2-Cycle) ADDR
DATA
Access of External Memory
MCD03287
Figure 2-2
Fetch Execute Sequence
Semiconductor Group
2-5
1997-10-01