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Gore42
1 Posts |
 Posted - 04/22/2006 : 08:46:56
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Hi everyone -
I got my Dual Power Willem programmer in the mail a few days ago, with the intent of programming my EPROM, a 2732a.
First, I looked up the specs for the chip, and made sure that it needs to be burned at 21v. So, I set the VPP to 21 volts, the VCC to 5 volts, set the dip switches, arranged the rest of the jumpers according to the software specifications. I unplugged the USB power and used a 12v, 300mA power supply.
Then, I tried to burn it, and it didn't work.
Then, I got my head out of my A**, and realized that the chip I was trying to burn wasn't blank! EPROMs, of course, have to be erased with a UV light eraser. I didn't have one handy, but I did buy a few blanks, for a few bucks each.
So, I tried it again with a blank chip, and it worked beautifully... no problems at all. I had read a few posts on this forum about people having trouble burning this EPROM (or the 2732 in general) with the Willem programmer, so I thought that I'd post up here and say that it works just fine, no worries. You don't even have to be a genius, apparently :)
Good luck, everyone!
Matt Gore
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DL
USA
46 Posts |
Posted - 04/23/2006 : 09:31:06
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Hi Matt,
quote:
Originally posted by Gore42
So, I tried it again with a blank chip, and it worked beautifully... no problems at all. I had read a few posts on this forum about people having trouble burning this EPROM (or the 2732 in general) with the Willem programmer, so I thought that I'd post up here and say that it works just fine, no worries. You don't even have to be a genius, apparently :)
I'd advise caution in making these kinds of assumptions.
All Willem-based programmers, except the Willem 4.1, will have voltage drop problems with NMOS EPROMs. The magnitude of the voltage drop will depend on the programmer. Some use a transistor that can handle the current better, but none will be able to eliminate the voltage drop enough to make the programmer realiable. I've measured voltage drops of 2V (the device was being operated at 3V!!).
As you become more experienced with these programmers, you'll learn that programming and verifying a device in your programmer doesn't guarantee the device operate correctly in the intended circuit. Read the post I have on willem.org in the General section about programming margin.
If you're programming EPROMs for fun and no lives or livlihoods will be at risk, this isn't as important. Otherwise, do everyone a favor and learn more about what you're doing so you don't get someone killed.
You're right, it doesn't take a genius. But having knowledge about EPROMs can't hurt. You need to know how to insure sufficient erase and program margin and you can't do this if you perform operations at incorrect voltages. Doing everything at 5V (or whatever your programmer is actually providing) can't guarantee EPROMs are programmed reliably.
HTH,
Dennis |
Edited by - DL on 04/23/2006 09:34:33 |
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Programming 2732a EPROM with Dual Power Willem
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