PERSYST TIME SPECTRUM 384 -  I/O PORT USAGE OF CLOCK.COM SOFTWARE
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MAY 2015
 
The following information was provided by Maelgrum of the Vintage Computer Forums.
The information can help identify I/O port conflicts.
 

Base Ports: 0x350, 0x250, 0x2C0 (auto scanned)

Looks like for base ports 0x350 and 0x250, lower 16 chip ports addressed directly:
0x350 - +0x00
0x351 - +0x01
..
0x35F - +0x0F
but higher 16 chip ports addresed at base port + 0x3F0 + n address:
0x740 - 0x10
..
0x74F - 0x1F
for base port 0x2C0 - port range is ordinary, 0x2C0 - 0x2DF
Chip port addressing: direct, 32 ports

Chip: NS MM58167 (HM68167, UMC UM82C8167)

Command line options:
/S - set DOS time from RTC data, and quit
/I - input date and time from command line

+0x02 Counter - Seconds (bcd, 0x00..0x59)
+0x03 Counter - Minutes (bcd, 0x00..0x59)
+0x04 Counter - Hours (bcd, 0x00..0x23)
+0x06 Counter - Day of month (bcd, 0x01..0x31)
+0x07 Counter - Month (bcd, 0x01..0x12)
+0x09 RAM  - Month copy (bcd, 0x01..0x12)
+0x0A RAM - Year minus 80 (binary) (0x00 is 1980, 0x01 is 1981 … 0xFF is 2235)
+0x0B RAM  write 0xDE
+0x0D RAM