Z8018x Family
MPU User Manual
251
Bus Control Signal Conditions
BUS AND CONTROL SIGNAL CONDITION IN EACH MACHINE
CYCLE
* (ADDRESS) invalid
Z (DATA) high impedance.
** added new instructions to Z80
Table 51. Bus and Control Signal Condition in Each Machine Cycle
Machine
Instruction
Cycle
States
Address
Data
RD WR MREQ IORQ M1 HALT ST
MC1
T1T2T3 1st Op Code 1st Op
0
1
0
0
1
0
0
1
1
1
1
1
1
1
1
1
0
1
0
0
1
0
0
1
1
1
1
1
1
1
1
1
0
1
0
0
1
0
0
1
1
1
1
1
1
1
1
1
0
1
0
1
1
0
1
1
Address
TiTiTiTi *
Code
Z
ADD HL,ww
MC2
~MC5
MC1
MC2
T1T2T3 1st Op Code 1st Op
Address Code
ADD IX,xx
ADD IY,yy
T1T2T3 2nd Op Code 2nd Op
Address
Code
MC3
~MC6
TiTiTiTi *
Z
MC1
MC2
T1T2T3 1st Op Code 1st Op
Address Code
ADC HL,ww
SBC HL,ww
T1T2T3 2nd Op Code 2nd Op
Address
Code
MC3
TiTiTiTi *
Z
~MC6
UM005001-ZMP0400
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