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Bit
7
6
MWI1
MWI0
R/W
R/W
Figure 19.
Memory and I/O Wait State Insertion (DCNTL – DMA/Wait
Control Register)
The number of Wait States (TW) inserted in a specific cycle is the
maximum of the number requested by the WAIT input, and the number
automatically generated by the on-chip Wait State generator.
Bit 7, 6: MWI1 MWI0, (Memory Wait Insertion)
For CPU and DMAC cycles which access memory (including memory
mapped I/O), zero to three Wait States may be automatically inserted
depending on the programmed value in MWI1 and MWI0 as depicted in
Table 3
Table 3.
Memory Wait States
MW11
MWI0
0
0
0
1
1
0
1
1
Bit 5, 4: IWI1, IWI0 (I/O Wait Insertion)
For CPU and DMA cycles which access external I/O (and interrupt
acknowledge cycles), one to six Wait States (TW) may be automatically
5
4
MWI1
MWI0
R/W
R/W
The Number of Wait States
0
1
2
3
Family MPU User Manual
UM005004-0918
Z8018x
29
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Do you have a question about the Z8018 Series and is the answer not in the manual?
Questions and answers
are there a timing diagrams for PUSH and POP instructions?
The timing diagrams for the PUSH and POP instructions for the ZiLOG Z8018 Series are as follows:
POP Instruction (e.g., POP IX or POP IY):
- Machine Cycle 1 (MC1): Fetch POP opcode.
- Machine Cycle 2 (MC2): Fetch address code.
- Machine Cycle 3 (MC3): Read from memory at SP (Stack Pointer); data goes to low byte (e.g., IXL or IYL).
- Machine Cycle 4 (MC4): Read from memory at SP+1; data goes to high byte (e.g., IXH or IYH).
PUSH Instruction (e.g., PUSH IX or PUSH IY):
- Machine Cycle 1 (MC1): Fetch PUSH opcode.
- Machine Cycle 2 (MC2): Fetch address code.
- Machine Cycle 3 (MC3): Decrement SP by 1 and write high byte (e.g., IXH or IYH) to memory at SP.
- Machine Cycle 4 (MC4): Decrement SP by 1 and write low byte (e.g., IXL or IYL) to memory at SP.
Each machine cycle includes three T-states (T1, T2, T3), and memory control signals (such as MREQ, RD, WR) are active as needed during these cycles.
This answer is automatically generated