[Mark1960]

I took a look at the Lattice parts, very similar range to the Altera. Also very similar cost from Utsource, about $7 each, though that might not be an entirely reliable source.

Lattice are available from Digikey but at $25 each it's not really worthwhile by the time we add RAM, PCB and assembly.

We need a minimum of 38 input output pins, 4 will be used for JTAG as we want to allow for reprogramming, and we would want a few more to control the RAM. This means we are looking at 100PQFT or 100TQFP type packages in either Lattice or Altera.

I would probably pick Altera as I have had the Quartus package installed on my laptop in the past and used a USB blaster to program Cyclone IV.

I'd probably use schematic design, but will take a look at dominicbeesley's VHDL version if we can come up with a possible physical design that works.

I have a couple of EPM7128S in 100PQFP that I was going to try to use in an SPI SD card reader, this gives 78 pins of IO, so it might simplify pcb routing for a module if all the RAM connections were mapped through the CPLD.

Just a rough layout to show the main components would fit, if the pin header can be SMT with some confidence that it doesn't pull the pads from the board when its unplugged from a 40 pin DIL socket.

It would be a little wider than a 40 pin DIL IC, about 0.8" instead of 0.6".