Hi John, I plan to tonight - btw still have not gotten IDE board to work yet with 68K (I think the problem is with writing registers - read seems to be OK so the pWR* maybe the issue) - though I did get the disk select to work with the mods I have made so far. Also on you monitor code you will have problems in your IDEWr routine as you do an ori with a memory location which is a port - the 8255 will not be able to do the read modify write so you need to do an ori with register and move the register to the port - I fell into same trap - I think a long session with Mr. Logic Analyzer and I will figure out what is going on.
Dave On Thursday, July 17, 2014 12:32:58 PM UTC-5, monahanz wrote: > > Hi Dave, just wondering if you had a chance to look into this pWR* signal > issue on the 68K board. > > John > > > > > > *From:* [email protected] <javascript:> [mailto: > [email protected] <javascript:>] *On Behalf Of *yoda > *Sent:* Saturday, June 28, 2014 8:20 PM > *To:* [email protected] <javascript:> > *Cc:* [email protected] <javascript:> > *Subject:* Re: [N8VEM-S100:4411] S100 68K issue > > > > z80 has plenty of margin - 250ns data valid after pWR* goes hi. I am > seeing about 10 - 20 ns but not consistent. Need to figure out how to > shorten pWR* or get data to be valid longer. I guess I will be getting > intimate with Wilcox book on his S100 state machine. I believe Pontius > experienced that is was very marginal. Guess you have been lucky John. > > > > Dave > > On Saturday, June 28, 2014 9:20:46 PM UTC-5, yoda wrote: > > Hi John > > > > Yes I think we need to get this resolved quickly before we do another > round of boards. I did find in Wilcox's book on page 331 that the chips > should be schottky devices which would be U38 and U42 which I have replaced > with 74F series - the prop console works but I would not say reliably yet. > I am putting it back on the logic analyzer now. I also notice compared to > that diagram the pWR* path has an extra inverter in it which would cause > and extra 7-10 ns delay which may be stretching pWR* out maybe too far. I > want to compare to Z80 board after I take another snapshot on the analyzer > - I think pWR* is getting delayed too long. The circuit you are thinking > of in the next post is the one that generates A0 from LDS and uses an RC > circuit on one of the legs - that seems to be working ok as the address > lines look solid. I will continue digging and let you know - think we > should delay the 68K board until after you get back. Have a fun vacation > > > > Dave > > On Saturday, June 28, 2014 6:06:41 PM UTC-5, monahanz wrote: > > Dave I have not had a problem with that board with the Propeller Console > IO board at all. Have not run it with the IDE board. That said I could only > get about 6MHz out of a 10Hz chip. I know Todd is about to order another > batch, we should resolve this ASAP > I'm MIA for two weeks unfortunately > John > > John Monahan ([email protected]) > > On Jun 28, 2014 3:32 PM, "yoda" <[email protected]> wrote: > > Hi > > > > Wondering if people have been using the 68K board. I think I have timing > issue because pWR* is going HI at the same time the data is being released. > You can see this in attached LA capture. I think that is why I am not > getting characters from the prop console and probably explains why I have > not gotten reliable data from the IDE card either. The dual serial card > and memory work just fine. I have tried different clocks as well - this > one is at 2MHz so that should not be the issue. Was wondering if someone > had seen this and resolved. I will dig through the schematics and the > Wilcox book as well. I think once I have this resolved, I can get CP/M 68K > going. > > > > Thanks in advance > > > > Dave > > > > > > -- > 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] <javascript:>. > 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.
