Attempt at '816

[Chromatix]

BigDumbDinosaur wrote:

Something else to consider is GALs tend to be power hogs.

There are some which are specifically designed not to be. Atmel's ATF22V10CQZ - the Z suffix is the key here, standing for "zero static power" - energises the GAL array only when an input transition is detected, and still manages a 20ns nominal propagation time. It also advertises "pin keeper" circuits, and on the front page it states "CMOS and TTL compatible Inputs and Outputs" in boldface. In all other respects it behaves like any other 22V10.

Also available is the ATF22LV10CQZ, which can operate down to 3.0V Vcc, has a nominal 30ns propagation time, and all the above features - and in the DC characteristics even has a line item for Voh with a CMOS load, which is explicitly CMOS compatible. This line in the table is missing from the 5V-only model, despite the promise on the front page.

Mouser has them both in stock for about €2.50 each, depending on the package type you want.

For about an extra €, you can also have the ATF750CL, a 5V CMOS-compatible device with a static power below 1mA typical, and with more internal logic capabilities than a 22V10. Unfortunately its 3V equivalent (ATF750LVC) doesn't have the low-power features, so its static power is in the 100mA range.

[akohlbecker]

What do you use to program the ATF750CL?

[Chromatix]

WinCUPL and at least some standard 22V10 programmers should be able to handle it. The programming algorithm is supposed to be the same as an Atmel 22V10, just with a bigger gate count.

[BigDumbDinosaur]

Chromatix wrote:

...and on the front page it states "CMOS and TTL compatible Inputs and Outputs" in boldface.

The outputs are TTL. VOH is 2.4 under load, clearly not CMOS.

[Chromatix]

The ATF22LV10CQZ most definitely has CMOS output drivers. Just look at the output source current charts in the datasheet. Same with the ATF750LVC. The common factor here is that these are devices specified to run with a 3V supply, but they'll also work just fine at 5V.

The situation is indeed less clear with the 5V-only devices. It might be wise to use them with devices having TTL-compatible inputs, but I think they will statically pull up all the way to the rail, which would be a power saver.

[akohlbecker]

Chromatix wrote:

WinCUPL and at least some standard 22V10 programmers should be able to handle it. The programming algorithm is supposed to be the same as an Atmel 22V10, just with a bigger gate count.

I'm not aware of any hobbyist-level programmer able to program the ATF750s, what are you using?

[Chromatix]

Dataman S4 - as far as that's concerned it's "just another GAL" and will fit in the same adapter module.

There's also an open-source GAL programmer based on an Arduino which lists support for the ATF750 series, alongside various other Atmel GALs.

[akohlbecker]

Chromatix wrote:

Dataman S4 - as far as that's concerned it's "just another GAL" and will fit in the same adapter module.

Not really "hobbyist-level", at a few hundred euros, with only two available on eBay

Chromatix wrote:

There's also an open-source GAL programmer based on an Arduino which lists support for the ATF750 series, alongside various other Atmel GALs.

That's a work in progress branch that hasn't been updated for a while, not the main afterburner source. The author talks a bit about it here https://gitlab.com/DavidGriffith/minipro/-/issues/180. Hard to say whether it is usable / finished code.

[drogon]

akohlbecker wrote:

Chromatix wrote:

There's also an open-source GAL programmer based on an Arduino which lists support for the ATF750 series, alongside various other Atmel GALs.

That's a work in progress branch that hasn't been updated for a while, not the main afterburner source. The author talks a bit about it here https://gitlab.com/DavidGriffith/minipro/-/issues/180. Hard to say whether it is usable / finished code.

I guess the only way might be to built it and try to use it - which I might be tempted to as I am thinking of a re-spin of my '816 board for some bizarre reasons which will involve re-programming the GALs which right now will mean I need to blow the dust off an ancient WinXP laptop and the G540 and hope they still work...

-Gordon

[gfoot]

These aren't supported on the commonly-used XGecu Pro TL-866 due to hardware limitations, but my understanding is that they are supported on the XGecu T56, at least through the Windows programming software. It's worth checking the official supported parts list online before committing to a particular programmer.

[BigDumbDinosaur]

gfoot wrote:

These aren't supported on the commonly-used XGecu Pro TL-866 due to hardware limitations, but my understanding is that they are supported on the XGecu T56, at least through the Windows programming software. It's worth checking the official supported parts list online before committing to a particular programmer.

Just a little update to this...the XGecu Pro T56 programmer I purchased earlier this year (2025) supports the ATF750.  I acquired an ATF750, programmed it with logic previously written for the 22V10 and then ran it in my homebrew GAL tester.  All combinations of input produced the correct outputs, thus proving that the device was correctly programmed.