Hi John, Yeah - I don't seem to see much effect with the jumpers but I have 6 to 9 and my board is working fine. 3 to 4 doesn't make sense from reading the book.
Dave On Friday, July 18, 2014 12:15:01 PM UTC-5, monahanz wrote: > > Interestingly Dave when I jumpered P2 2, or 4, or 6,... to 9 for I/O wait > states, the monitor would not sign on. If however I leave it jumpered 4 to > 3,(13), or 4 to 11, it comes up fine. I using two different boards a 68010 > and a 68000, both with a 12 MHz oscillator. 4 to 15 also hangs, Worse, > no jumpers seems to work fine as well. > Now I'm really confused! > > John > > > > On Thursday, July 17, 2014 7:23:30 PM UTC-7, yoda wrote: > >> Hi John, >> >> Re-wiring the circuit gives no noticeable difference. I see between 40 >> and 50 ns delay of release of data after pWR* going high. I don't know if >> that is enough or not. I attached a typical trace here. If you look at >> pages 331-337 of Wilcox he discusses the circuit and the issue with write. >> The circuit is not the same as in the schematics on page 494-495 as the >> logic and path lengths have been changed. I am not sure what to do - the >> console I/O and serial I/O are working fine but I am not sure on the IDE >> board yet - I need to but the logic analyzer on the 8255 or IDE port and >> look at what data is being put on the ports and make sure it matches what I >> am sending. I probably have a couple of days of debugging here so if you >> want to wait on pushing the design out until I have the IDE board working >> with it, I would feel more comfortable. >> >> Also in your write up in the end you state that jumpering P2 3-4 makes >> all S100 bus I/O have 2 wait states - the way I read the schematic you are >> adding 2 wait states to M1 pgm fetches. I think you want to jumper 4 to 1 >> or 7,9 for 2 waits on I/O accesses. Look at 479 as it gives several >> examples as how to set the jumpers. >> >> The net of above - no matter what frequency you run at, U37, U38, U42 and >> U40 (if you can find one) need to all be F logic. The state machine is >> independent of processor frequency (I think Pontius found that in his bring >> up and is in his reference notes on the wiki). >> >> 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.
