Miscellaneous – Zilog Z80180 User Manual
Page 187
Z8018x
Family MPU User Manual
172
UM005003-0703
Miscellaneous
Free Running Counter (I/O Address =
18H
)
If data is written into the free running counter, the interval of DRAM
refresh cycle and baud rates for the ASCI and CSI/O are not guaranteed.
In IOSTOP mode, the free running counter continues counting down. It is
initialized to
FFH
during RESET.
Free Running counter (FRC: 18H)
Bit
7
6
5
4
3
2
1
0
Bit/Field
Counting Data
R/W
R
Reset
?
Note: R = Read W = Write X = Indeterminate ? = Not Applicable