GAL chips seem expensive to get started with, since programmers cost hundreds of dollars and even ISP cables aren't cheap.
Is there a cheaper way?
GAL chips seem expensive to get started with, since programmers cost hundreds of dollars and even ISP cables aren't cheap.
Is there a cheaper way?
I'm not even sure GALs are still around today. CPLDs and FPGAs are preferred I believe, though I'm no expert. You can dig up development kits from digilentinc.com. There's a CPLD kit for $18 and the USB JTAG programming cable is $50. Those parts are Digilent C-Mod and JTAG-USB Cable. I believe the software (at least starter software) is free. Good luck!
Here is the schematic for a simple home-made PCB for experimenting with Xilinx XC9536 CPLDs. It has a connector for a Xilinx programming cable, a socket for a crystal oscillator and an LED, as well as a small prototyping area. The artwork file is available.
Standard GALs need funky voltages and waveforms for programming. Lattice do some 'ispGAL' products which added an IS interface, but unless you want to stick to DILs and/or 5V, low-end CPLDs are more capable and easier to program.
A simple GAL programmer: http://elm-chan.org/works/pgal/report_e.html
And if you want to know how to program: http://www.rexfisher.com/Downloads/CUPL%20Tutorial.htm