I continue to have no luck with the RTC. Strange symptoms... I can set the clock with the CP/M Z-RTC program, but it doesn't change over time.
I can set the clock with the 8088 monitor V10.32 "E" command and only the seconds and day portions will change. I've swapped out the battery, xtal, DS12885+, and support IC's. I've ordered a DS12887 to try, as that should eliminate the xtal and battery as issues. The rest of the board (Eprom access, Interrupt controller, Timer) work fine. I still haven't tested the Keyboard controller section. I'm almost ready to just build up a second board. Any ideas or suggested troubleshooting procedures? - Gary On Thursday, July 17, 2014 10:03:16 AM UTC-4, [email protected] wrote: > > John - > > Crystal should be here in a few days, finger's crossed. > > I'll also try simplifying the system tonight and using the Z-RTC program > under CP/M3 instead of the 8088 board. I'll see if that makes any > difference. > > - Gary > > On Thursday, July 17, 2014 12:36:10 AM UTC-4, monahanz wrote: >> >> Gary, just rechecked mine (been a long time since I was there!). The >> clock seems fine for time and date. Was many months ago since I set it. >> The only thing I see an error with is the century (“20”) came up as ?? so >> it read as ??14/07/16 >> >> When I reset the date it appears OK i.e. as 2014/07/16. On reset and >> power down it comes back correctly as 2014. Not sure what the problem >> is/was. >> >> >> >> Sorry don’t have a suggestion for you. Hope it is the crystal. >> >> John >> >> >> >> >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *[email protected] >> *Sent:* Wednesday, July 16, 2014 11:37 AM >> *To:* [email protected] >> *Subject:* [N8VEM-S100:4612] MSDOS Support V2 PCB RTC problem. >> >> >> >> I'm pulling out my hair trying to access the DS12885 RTC on the MSDOS >> Support PCB. >> >> The rest of the board (timer, interrupt and EPROM) appears to be >> functioning properly. I have not tried the mouse/keyboard section yet. >> >> I can see low pulses on Pins 14/17 as expected. I'm using the "E" >> command from the 8088 board for testing time/date in V10.3 of John's >> monitor software. >> >> When I set the time the seconds and day will program, but the >> hours/minutes/year/month remain gibberish. I also get errors when entering >> the "X" MSDOS menu - either that the RTC is stuck or that invalid BCD data >> exists. >> >> I've swapped TTL and DS12885. I've also changed the 32.768khz xtal. >> When I scope pins 2/3 on the DS12885 (XTAL) I can see somewhat noisy pulses. >> >> Would the DS12885 at least store the date if the xtal isn't oscillating >> properly? It looks like the RTC shares most of the same address/data >> circuitry with the other sections. The 8088 has a 8 mhz clock, could speed >> be an issue? >> >> Any thoughts or hints appreciated! >> >> - Gary >> >> -- >> You received this message because you are subscribed to the Google Groups >> "N8VEM-S100" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
