Date   : Fri, 12 Jan 1990 06:35:33 GMT
From   : rzh@lll-lcc.llnl.gov (Roger Hanscom)
Subject: CP/M Clock

There are plans in the Jul/Aug 1981 Microsystems Journal (p. 64) for a S-100
clock based on the MSM5832 chip.  It uses an 8255 PPI chip for the clock
port.  Those of you with eleven bits of unused parallel port could probably
rig up the clock chip on that with a minimum of parts count.  I just got done
wire wrapping the complete circuit for my S-100 system, and it works fine.
Unfortunately the software published in the article got munged, so if
anyone is interested, I can provide listings of what I came up with.  I've
got two clock-read entry points in ROMed code.  One reads the clock and
returns to the monitor (a monitor "date" command is next!), the other does
a ret just like any other subroutine, so it can be called from an application.
When CP/M boots, it prints the date and date at the top of the screen, and I
put the day and date on printed listings.  I just wish that there was an
easy way to timestamp files in CP/M 2.2 @:^).

              roger               rzh@lll-lcc.llnl.gov