STE V1.5 32MHz BOOSTER - STATUS

[exxos]

It does seem strange you even get problems with PD - if you're not specifically trying to use it it should not be an issue.

I was talking to Atmel a great deal in 2015 about it all.. A quick re-read and they think my programmer was enabling the PD feature as it didn't actually have a proper device number listed.

I am pretty sure I stopped using pin 4 and the problems went away. Also seems Atmel sent me a modified jed file to turn off the feature, and it still didn't work. So I assume I just gave up with them at that point... I will probably have to buy a different programmer to program them

[exxos]

ATF chips should be here sometime tomorrow

The irony in all this is...

22.jpg (61.3 KiB) Viewed 6999 times

Pin 4 isn't actually used, so I just need to tie to 0V I think to disable the PD thing..

I guess that is what happens when I copy paste bits of code year after year

[exxos]

I've not connected pin 4 on the PCB, but so far we are powered by Atmel! Just started the machine doing its loops in GB6...

IMG_3604.JPG (119.05 KiB) Viewed 6975 times

[exxos]

I got distracted yesterday with other things, so did not do much testing..

But yesterday the ATF chip booted but failed to complete a full loop.. I have actually removed the series resistor with the schmitt buffer and removed the small capacitor as well... It was last night, and it got to somewhere around 35 passes then quit to desktop :-\

I started this running this morning again and it is currently at about loop 48. So almost been going about three hours.. I need to know how long it runs for before it crashes so I can then retest again. This way I can try and find out if it is some sort of thermal fault or not.

I think part of the problem is that the GAL's output voltage is not consistent and sometimes does not drive the correct voltage levels for the buffer.

I am also half thinking that the tolerances of the GAL's drift as the chip warms up, but again I needed it to fail so I have a reference of how long it runs full with the ATF chip.

I'm also half wondering if the OSC itself as it drives the clock pin on the GAL, if you should have the resistor put back, it is only a guess, but if the voltage is higher than the GAL likes, maybe that is heating up junction inside the chip causing it to fail..

So I need to scope stuff out, but I do not want to start probing things while I am doing the soak testing as it may well cause it to crash.

The basic good news is that the ATF chip is definitely working considerably better than those other GAL chips.. So this is the least a huge step in the right direction..

[exxos]

Loop 108, So it least this particular ATF GAL works

Is been running for around 7 hours now.

So will start doing some scoping tests...

IMG_3633.JPG (17.28 KiB) Viewed 6939 times

EDIT:

Nope, can't see any real difference between the "duff " GAL's and the ATF in terms of voltages. Tried the scope on every pin in x10 and x1 modes, makes no odds. So a unsolvable mystery I guess

Will start testing a second ATF see what happens now...

[PhilC]

Just chalk it up to WTF

[exxos]

I just think they are sub-standard somehow. I mean they can run at 8MHz, but the only difference in 36MHz is the flip flops are active more. So I think the internal flip flops can't run fast for some reason. They seem to be 15ns parts stamped as 7ns, no surprise there, but 12ns should be fine, ATF's are 15ns and work fine. I think these ATF chips run cooler than the GAL's as well.

[exxos]

The second ATF GAL has hit 76 passes so far (About 5 hours run time). So looks like the ATF chips are a winner.

For the hell of it, I am going to try "turbo mode" and 40MHz again on this board.. not expecting it will work.. but I just want to be sure...

[PhilC]

Sounds like you've got much more of a chance now. Well done.

How do the atmel gals compare price wise? And would they be pin compatible with the likes of a 20V

[exxos]

How do the atmel gals compare price wise?

No price difference really.

would they be pin compatible with the likes of a 20V

They are the same as a 22V10 GAL, just with a couple extra features. I never looked into any other GAL pinouts.