At 01:00 PM 3/4/2011, Philip Pemberton wrote: >On 04/03/11 19:36, Dwayne Reid wrote: > > That's the software side. The hardware side is also a little > > challenging: the SPI buss and those shift registers are running from > > 5Vdc. Most modern CPLD's seem to be 3.3V or lower. > > > > So: I'm looking for suggestions for a small to medium size CPLD that > > runs at 5V and has at least 40 macrocells. > >Heck, the I/O pads are 5V tolerant -- if your hardware doesn't mind >being driven from 0V/3.3V TTL, you can do away with the buffers and wire >the CPLD straight in. I considered that but the existing shift registers are HC rather HCT. >Only thing you'd need to add is a low-current 3.3V power supply. This unit actually has 3.3V, 1.8V, 1.25V rails for the TMS320xx DSPs=20 and all of the codecs. But these shift registers are being used to=20 control analog gate packages that want to see a 5V control signal. Thanks for the suggestions! dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .