On 2012-10-08, at 17:11, Gerrit Heitsch wrote: > From my checks with a scope, the _CS line for the Char-ROM is the slowest of them all, going LOW about 200ns after PHI0 goes LOW, so with a 150ns EPROM, you should still be OK I use 200 but tried with faster one too. > and from the picture you posted, you still get correct looking chars so the EPROM access in general works. "Jein".. The characters in the case when the striped IDE64 picture is displayed can look all good or can also jitter on the edges. Interestingly only/mostly on the left side of the screen. Especially when switched to the DIN charset. So it works also "sort of" > Also, you said that sometimes the system comes up OK and other times it doesn't. Yes, when I plug the adapter board in, it boots most of the times. But when I e.g. placed the LS11 on the breakout board it never booted OK. Only with DolphinDOS I got a BRK and mem-monitor at $44xx (sic!) > To me that really looks like a floating input somewhere. Frankly, I would prefer this, rather than a failure of the whole concept ;-) > Can you post the schematics you used? http://dl.dropbox.com/u/58002657/cbm/c64/rom_adapter_0.png > And if it works, how stable is the system? Looks stable. At least I can input few lines of BASIC and let it run. I didn't check anything with serial bus though. > How long are the lines between the board and your circuit? The final one is supposed to plug in directly to the sockets. For the proto I test now I ran two wires with _BASIC and _CHAROM directly off PLA to the adapter board. Wires are about five inches each. > You can run an EPROM with _CS and _OE tied LOW and change the address inputs. After tAcc, you will see the the expected output on the data lines. That's how the PLA-replacement using a 27C512 works. I shall try this too out of other ideas.. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2012-10-08 18:00:05
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