Post by thread:Universal Device Programmer

Hi! I want to build a universal programmer which programs E(E)PROMs, PLDs, Microcontrollers, etc... and the sort of devices the commercial ones program. I couldn't figure out the base idea yet. I want to build at least a 40 pin (48) device. I think it would be great to build it maximally flexible programmer, so on all the 40 (48) pins it could switch the Programming voltage (which is adjustable from software), the Vcc (also adjustable), a bidirectional digital I/O, and GND if neccesary. This leads to a quite complicated hardware. But with special ICs these functions could be accomplished with very few parts. I have 5-7 ideas on the pin circuit (ie. the circuit which connects to all the pins), but all have drawbacks (generally 4 or 5 functions go well, but adding an extra switching option requires much more resources. I was considering analog multiplexers, but there's a problem with the maximum current. I have though of using AllegroMicro devices. How could I switch the GND without the need of Relays? Any help would be appreciated. Thanks: cotan