From: email@example.com (Al Borowski)
Subject: Re: What would you want in an EPROM programmer?
Date: 25 Sep 2002 17:41:00 -0700
References: <firstname.lastname@example.org> <3D9197A2.6650CA3E@kth.se>
NNTP-Posting-Date: 26 Sep 2002 00:41:00 GMT
Uwe Zimmermann wrote in message news:<3D9197A2.6650CA3E@kth.se>...
> except for the fact that there is a zillion good designs already out
> there, I don't want to disencourage you. I myself wokred out a design a
> while ago, but then finally decided to buy a complete kit instead...
True, but as I said, this is for teaching myself about EPROMs
> some comments to your questions:
> Al Borowski wrote:
> > Hi,
> > I'm in the middle of designing an EPROM programmer.
> > 1. The programming voltage is 13V - is this OK for most modern
> > EPROMS's? I could make it varible by the PIC, but I don't know if it's
> > worth the effort.
> no chance, without a programmable voltage I would not dare to use such a
> thing. It should at least comply to burning and verifying conditions
> according to the spec sheets of different memory chips, i.e. a varibale
> supply voltage 5V and 6V of the memory chip and different programming
> voltages, at least something like 5V (Flash), 12V, 12.5V and perhaps
> 14V. Neverheard of any memory chip being programmed with 13V.
Funny, All the ones in the dick smith cattledog ask for 12.75V, with
13V well within limits. I wasn't going to make the supply voltage
adjustable (leave it @ 5V). However, It shouldn't be too difficult to
implement a varible programming voltage.
> > 2. In order to allow many devices to be programmed, I was planning on
> > having a header, like an 8 bit ISA slot, on the programmer. Different
> > daughterbaords for different devices could be placed into this header.
> > I was planning on getting the PIC to recogonize which daughterboard
> > had been inserted and adjust the programming parameters accordingly.
> > Does this sound like a good idea?
> not to me.
> If you are planing to build a decent programmer, it should read out the
> chip ID to determine the programming parameters. The need to use
> different adapters for chips in similar packages increases the
> probability of user error while at the same time reducing the ease of
I agree - had I more time then I do now, I'd like to do that. However,
I don't know if all chips support a chip ID, and even if I did it
would be a huge pain in the neck to collect all Id's into a database.
The reason I want to stick with the daughterboard idea is it allows
for bizarre pin-outs, and also allows flexibility. For instance, I
could put a resistor on the board that controls the programming
I'm not going to produce this thing commercially - this is just for
> > 3. Since FLASH ROM's are popular nowadays, would it be useful to
> > include flash rom support into this thing?
> should be fairly easy to implement, once you get the programming voltage
> set correctly. The programming algorithms of Flash ROMs are very similar
> to those of EPROMS.
> > 4. Finally, what LED indicators would be useful? I was thinking power,
> > RS-232 comms and Write.
> nice add on, but not even worth discussing. Just add those to the
> corresponding lines in your design (e.g. TxD, RxD, /PGM) and it will be
good idea - saves me PIC pins.