On Sat, Mar 9, 2013 at 9:28 PM, Tony Firshman <[email protected]> wrote:
> On Sunday, March 10, 2013, Dave Park wrote: > > > The Gold Card and Super Gold Card are quite different in this respect. > > > > The custom logic on the GC and SCG that I have are both Altera chips that > > max out at 50MHz, which gives a top CPU speed of 25 MHz. However, the SGC > > clocks the CPU at 24MHz, probably because that frequency allows faster > > memory transfers than at 25 MHz which could cause additional wait states. > > The 68EC020 was the fastest one made, 25 MHz, though a full 68020 was > > available as a 33 MHz version in a different package. However, the CPLD > > will not run at 66 MHz. > > > > The 68000 in that socket style did have an FN20 (20 MHz) version, and > > swapping the CPU and clock IC might have the desired result, or it might > > not. > > > > I don't know if the contents of the custom logic in the cards is the same > > or different, but both the ones I have here have EPROMS with the same > > contents, both labelled "SGC 2.49". > > > Again from memory but I am sure one logic chip (Altera EP1810?) now does > not work. They changed the spec in some way which broke SGC. Roy Wood > tracked down hundreds, and bought them. He managed to get his money back. > I still have Stuart H's programming adapters he bought for my Omnipro2 and > the code. > > > > > > > Tony > > On the upside, the EP of EP1810 means Erasable Programmable, so it is possible to buy and reprogram used ones in the correct date range. Sometimes, failed ones just have a flipped bit in their EEPROM and a simple reprogramming fixes them. That conversation deserves a separate thread. Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
