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 listReceived on 2012-09-20 18:00:53
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