Electronics > FPGA

A 5V CPLD in 2023?

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AK6DN:

--- Quote from: edavid on March 17, 2023, 02:04:56 am ---Could you use a 256Kx8 EEPROM (SST39SF020A) and a couple of 8 bit input latches?  That seems a lot simpler and cheaper than a CPLD/FPGA.

--- End quote ---

Depends on the function needed, which is not well described. An ATF1502AS (equivalent to an EPM7032S) is only US$3.50 in a PLCC44. ATF1504AS (EPM7064S) is about US$4.75.

Put it on a little carrier board wired up to the DIP28 footprint and program it as needed.

woofy:
I would suggest you first find out how much logic resources you actually need before trying to select a device. As you are already familiar with Lattice devices, I would suggest an HX8K board. The HX has 5v tolerant inputs (data sheet says not, but it is).  You just need level shift on the outputs and possible not even then as 3.3v outputs will drive 5v ttl inputs. Once you have sorted out all the logic you will be in a much better place to choose a real 5v device.

NivagSwerdna:
So... I sacrificed sleep for verilog... (quite tired now)...

Got some working verilog... and did a functional simulation and it is looking good.

For this design essentially it is 4-off 74LS194 and 1-off 74LS157 if you were to use 74-series.  The actual verilog is simpler as the actual function is a subset.



Seems to fit easily in a EPM7064SLC44-7

The simulation suggests it is actually doing something....



I just sort of grabbed ports and pins... I need to read the datasheet to understand if I should be using the square boxes.



I'm happy to invest in that programmer if required.  There is also a dev kit which I could probably sneak into the entertainment budget... https://www.kanda.com/products/Kanda/ATF15XX-DK3-U.html

This definitely seems like the right approach.

PS
I cannot get inline images to work... never mind.

AK6DN:

--- Quote from: NivagSwerdna on March 17, 2023, 09:44:53 am ---...
For this design essentially it is 4-off 74LS194 and 1-off 74LS157 if you were to use 74-series.  The actual verilog is simpler as the actual function is a subset.

Seems to fit easily in a EPM7064SLC44-7
...

--- End quote ---

You might even try targeting an EPM7032S (ATF1502AS) if your macrocell usage is below 32 cells..

... I now see that your macrocell usage in the pic in the prior post is only 20 of 64 cells, so a 32 cell EPM7032S (ATF1502AS) should work too.

mikeselectricstuff:
As most of the pins are inputs, I'd avoid the hassle of finding 5V parts, use resistors (e.g. in 4-way resistor networks) to get to 3.3v level and an HCT buffer to convert the outputs back to 5V

How fast does it actually need to be? Could you use something like an 8-bit PIC?
 

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