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Anything special about programming 27512 eproms ?

M

mc68010

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I bought a Willem burner off ebay a long time ago and it works fine for everything I've tried but, 27C512 and 27512 eproms. It can read them fine and it thinks it is programming them but, it never actually writes anything. I can program 27C256 and 27C010 just fine. I've tried about ten different eproms and it's no go.

I don't know if it's flaky hardware or the fairly buggy software these use. I have tried several versions of the software and nothing changes.

If I can't get this figured out anyone care to burn a quick eprom for me ? I erased the one I was replacing sure it would be a quick job but, I am never so lucky. I should have left the original alone.
 
What manufacturer and what exact part number for the 27C512s? This size hails from a time when programming algorithms were not uniform across manufacturers.
 
Chuck(G) said:
What manufacturer and what exact part number for the 27C512s? This size hails from a time when programming algorithms were not uniform across manufacturers.
Click to expand...

I have a few different ones but, they are all AMD. AM27512DC, AM27512-30DC, AM27C512-150DC, AM27C512-155DC
 
If you haven't yet, check the programming voltage.

Some chips cause quite a drain, and at least mine from ebay, doesn't regulate it properly - so when programming the 12.5V can easily drop to 10 or 11. I have to adjust mine all the time, quite a pain. Too much voltage and the chips overshoot, not enough and they undershoot or don't write at all.
 
Hmmm, nothing special. It is different in that Vpp is applied to pin 22 instead of Pin 1 as on the smaller AMD (e.g. 27C256) EPROMs. I wonder if it's a bug in the Willem software. Time to check some support forums, methinks.
 
Chuck(G) said:
Hmmm, nothing special. It is different in that Vpp is applied to pin 22 instead of Pin 1 as on the smaller AMD (e.g. 27C256) EPROMs. I wonder if it's a bug in the Willem software. Time to check some support forums, methinks.
Click to expand...

I'm not sure there is a support forum. I get the feeling these are just some opensource hardware project from a long time ago that the Chinese are just mass producing under 100 different names now. The software has never even reached version 1.0 and doesn't appear to be actively developed.
 
SpidersWeb said:
If you haven't yet, check the programming voltage.

Some chips cause quite a drain, and at least mine from ebay, doesn't regulate it properly - so when programming the 12.5V can easily drop to 10 or 11. I have to adjust mine all the time, quite a pain. Too much voltage and the chips overshoot, not enough and they undershoot or don't write at all.
Click to expand...

How are you adjusting your voltage ?
 
Also check you've set the switches correctly for the EPROM type - in the program I use it draws them on screen after you select the chip you want. I thought of that when Chuck mentioned about the programming pin moving.

On mine, not sure if its the same, there was a very very tiny trimpot that is adjusted with a jewelers flathead screwdriver. Instructions for setting Vpp were in the software, but I usually just increased it a bit and tried again until the chip was writing correctly. For something like a 27C512 you could just follow the instructions in the software - it should be fine.

With mine set to 12.5 (using their instructions) I could program 27C256, 27C512 no problems. But slow or older ROMs I had to set it a volt or so higher to compensate for droop and increase the timings (I can't remember the names, it's been a long time, but there were two sliders to adjust timings). When it arrived it was set so badly it wouldn't even program the 27C512 they sent with it! Also rather annoying, the chip they sent was zero-filled, so I had to erase it first :S

Of course I'm basing this on your controller/program being very similar to my ebay-special. So if bits don't make sense, that could be why. Also apologies for being so vauge, it's because I haven't used it in almost a year, just hoping I can point you in a direction for things to try.
 
I believe that the datasheet for the AMD 512Kb EPROM spec Vpp at 12.75V nominal +/- 0.25V. So 12.5V would be grazing the bottom edge of the range.
 
SpidersWeb said:
Also check you've set the switches correctly for the EPROM type - in the program I use it draws them on screen after you select the chip you want. I thought of that when Chuck mentioned about the programming pin moving.

On mine, not sure if its the same, there was a very very tiny trimpot that is adjusted with a jewelers flathead screwdriver. Instructions for setting Vpp were in the software, but I usually just increased it a bit and tried again until the chip was writing correctly. For something like a 27C512 you could just follow the instructions in the software - it should be fine..
Click to expand...

Mine doesn't have a trimpot. Just a couple jumpers for selecting VPP. Sounds like you got a higher quality one. They do seem to vary a lot. I think I have something wrong with mine. If I check the voltages in the hardware test of the application they are fine, or close to fine. I get 12.5 on Vpp and 5.6 on Vcc. The test readings are made with the eprom out though. When I pop in a 512 and read Vcc goes down slightly to about 5 but, it does read. When I try and program it all goes to hell though. Vcc drops to about 3 and Vpp nose dives down to about 2. It does this on USB power or a 12vdc@1a ac adapter. Vpp is showing up on the right pin though. Just not enough of it.

I am erasing some 256 right now to see what voltages do on those. I imagine they are probably ok since they program fine but, I am curious.
 
Chuck(G) said:
I believe that the datasheet for the AMD 512Kb EPROM spec Vpp at 12.75V nominal +/- 0.25V. So 12.5V would be grazing the bottom edge of the range.
Click to expand...

Doesn't appear like I am getting even that. Think something is seriously wrong with my burner.
 
I have a spare 27C512 and a trusty Data I/O. Tell me where I can download the file, and tell me the file format (binary, Intel Hex, etc.). I don't think you can attach a file via private message.
-Dave
 
My Data I/O 29B has let the team down. The EPROMs I have are AMD 27C512 and there must be something different about them as they require a V23 rev on the Unipak2B. The other 27C512's from Intel, etc only require rev V19 or less. And since my Unipak is at rev 21, I will need you to send me a device I can handle such as anyones 27512, or a 27C512 from Intel, Atmel, National, NEC, Signetics, Mitsubishi, or TI.
 
Thanks, Chuck. The OP has indicated he has some 27512's, but I was trying to save time by using one of mine. But it turned out to be an AMD27C512 which my burner can not handle. :oops:

If you have a couple of spare 27512 type devices you can burn for him, that would be great. Or he can send me some blank devices that I can burn.

The file he needs programmed is a Motorola S record file containing 64KB of data. That doesn't seem like much but it took almost 5 minutes for me to transfer the data via RS-232 to the burner. I'd better check the baud rate I have set in my Data I/O. You gotta love 1980 equipment.
 
Well, I checked my Xeltek Supepro and even an old M2L EZEP programmer--both handle AM27C512, no caveats. I don't have the AMD parts (I do have an AM27C010 and both handle that just fine), just the TI parts in 512Kb, so I wasn't able to check it.
 
Just checked my device list for the Unipak 2B and it requires V27 firmware and adapter 351B086 for the AMD 27C512, It's the Unipak 2 that requires V23 firmware to program that chip.

dave_m said:
My Data I/O 29B has let the team down...
Click to expand...
 
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