I also have a GQ-4X programmer and it's pretty good. It connects via USB but can also do the higher voltages by plugging in a 9V adapter. Only chip I wished it would support is the 68764. You're supposed to be able to add chip definitions but I havent tried yet. I generally get my EPROMS from ebay. I think the seller/store is ACPSurplus. Steve >________________________________ > From: Rob Clarke <crock@clarke-family.org.uk> >To: cbm-hackers@musoftware.de >Sent: Thursday, September 20, 2012 1:46:20 PM >Subject: Re: Char-ROM replacement > >Do you have a USB programmer that will program 25xx's without an adapter? I'm trying to find a new one to replace my old RS232 DOS based one but I'm getting very confused my all the Willem look-a-likes.... > >rob > >On 20/09/2012 19:00, Gerrit Heitsch wrote: >> Hello, >> >> since I had a C64 char ROM (901225-01) go bad this year, I was looking for a replacement. The pinout of the ROM matches the 2532 EPROM, but the only one I had was 450ns and that's too slow. I tried it, but all I got was a snow storm at power up. >> >> Then I found a few TMS2532-30 on ebay and got around to try 2 of them today. Those are fast enough, you get the expected picture at power up. >> >> So, we have a verified drop-in replacement for the char ROM. The 2532 is NMOS so it will get warm, but you don't need any adapter, just program it, and plug it into the socket. >> >> I also wanted to see how a ROM and the EPROM behave and used to the scope to look at the time between _CS going LOW and the state change on D0, showing me data being ready. The ROM did that in about 50ns! The 2532-30 took about 150ns. Quite a bit faster than the expected 300ns. Did TI just test for 300ns as highest speed back then and never bothered to see if any were faster? >> >> Oh, and there is a 2532A too, available in 250ns, but needs a Vpp of 21V instead of 25V. At least my programmer can't do that combination. >> >> Gerrit >> >> >> Message was sent through the cbm-hackers mailing list > > > Message was sent through the cbm-hackers mailing list > > > Message was sent through the cbm-hackers mailing listReceived on 2012-09-20 20:01:01
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