Zilog Z80180 User Manual
Page 199
Z8018x
Family MPU User Manual
184
UM005003-0703
IO (I/O)
IO addressing mode is used only by I/O instructions. This mode specifies
I/O address (IORQ is
0
) and outputs them as follows.
1. An operand is output to A0–A7. The contents of accumulator is
output to A8–A15.
2. The contents of Register B is output to A0–A7. The contents of
Register C is output to A8–A15.
3. An operand is output to A0–A7.
00H
is output to A8–A15 (useful for
internal I/O register access)
4. The contents of Register C is output to A0–A7.
00H
is output to A8–
A15 (useful for internal I/O register access).