On Feb 27, 2012, at 11:53 AM, Gerrit Heitsch wrote: > On 02/27/2012 08:44 PM, Groepaz wrote: >> On Monday 27 February 2012, you wrote: > >>> The only chip I could see a market for would be a drop in replacement >>> for the 6526. That one is fully digital and does die quite often since >>> it has direct connections to the outside world. >>> >>> The VIC is still easily available and doesn't fail very often. Same for >>> the CPU (6510 or 8500). >> >> yeah, CIA is also more realistic to reproduce (today) in some cheap way >> (perhaps without needing an fpga even). > > There has been a project to replace the ULA in a ZX spectrum with a programmable logic chip: > > http://www.zxdesign.info/thebeginning.shtml > > 68 pages, but well worth reading how he reengineered the ULA with TTLs at first. He didn't specify the CPLD he used at the end, but if the ULA function fits in there, a CIA should be no problem. Nice blog. He said he used a XC95144, which has about 3200 gate equivalents. That's overkill for a 6526. It's about $5.80 from Digi-Key. -Nate Message was sent through the cbm-hackers mailing listReceived on 2012-02-27 21:00:09
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