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5v CPLD 'Is it possible?' fun :)

Started by PhyChris, January 23, 2022, 12:36:36 PM

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Sup, Just built a CPLD program board and blew myself away when it worked! (Auto detect, program, erase and reprogramed!)

my first board build! coming from someone who still thinks of CAPs as water towers and not some 'Component decoupling' thingy

NOW! The "Is it possible part?" is this thing fast enough to connect to a Sega Genesis System BUS and act as a 'Super cheap' Game genie?

Edit: I have a bunch of ATmega328P's to use if it would require a Cheap CPU

Edit2: I somehow forgot to name the chip lol   ( ALTERA MAX 7000 series - EPM7128SLC84-15N ) 5v logic Cheap as hell!


Yes, this should be fast enough to do address decodes, but the question is - do you have enough I/Os, and is there enough logic space to accomplish what you want ?

For greater speed, greater capacity, and greater number of IOs, you would likely need to switch to a different family of chip, which would almost certainly be 3.3V, and need level-conversion.  It's not the end of the world, just an inconvenience to add more chips.

You might want to try a printed circuit board design for anything more complex than that - they are very reasonably-priced when you order from China (but there's a short learning curve to get going on PCB design).


You are right about everything. The wiring is a HUGE deterrent. the chip has enough I/Os '64' and it would be cool to use 90s tec for it but damn wiring takes forever and the point when you need to label the wires. The ATmega328P idea was if it had to use a CPU Clock it 3x68k, it would do the address comparison and it would swap CE and send the EPM7128SLC84 the new data to drop in. the whole cart would use the Genesis to power and 68k Clk 7.6mhz 

Wires everywhere. the time it takes to wire something like this is not worth it Time = money

learn PCB design. There is a small bit of learning but lots of tutorials online (Its FUN)

Thanks dshadoff

Edit: I stuck a L78S05CV regulator in my model 2 system and everything lol!