[Coco] eprom burner

[Gene Heskett]

On Monday 29 March 2010, Steven Hirsch wrote:
>On Mon, 29 Mar 2010, Brian Blake wrote:
>> I'm looking at buying an eprom burner. I have a few hobbies (including
>> CoCo's) that require being able to program eproms, PIC's, etc... I've
>> looked into a number of different types, but, was wondering what
>> everyone else uses. I've been looking at this Willem devide:
>>
>> http://cgi.ebay.com/PCB5-0-Willem-EPROM-Programmer-PIC-BIOS-Shipfrom-USA
>>_W0QQitemZ360201810162QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item53dd
>>b370f2
>
>That looks like a nice rendering of the Willem design and it's about 1/2
>of what I paid for mine two years ago.  If you're planning on burning
>older low-capacity EPROMs, you will definitely want an external power
>supply.
>
>Also, remember that this is "open source" hardware and not a commercial
>product.  They are not always simple nor straighforward to use, but the
>information is all out there.
>
>Be sure your computer has a real parallel port on it (the USB cable is for
>power only, believe it or not).  I am not confident that the software will
>work properly over a USB to parallel adapter.  Worst case, you may have to
>pickup a PCI parallel card.  I bought one of these from Newegg last year
>for about $15.
>
>Steve

No, it won't work over a usb<->parallel adaptor.  USB's worst case timing 
constraints cannot operate at the timings these devices need to function 
correctly.  All you will do is fry stuff because a 10 microsecond timed burn 
cycle might be stretched to 10 milliseconds or worse by USB.

Parport cards are cheap, I have a Rosewell dual port I paid less than $30 
for.  BTW, there are some parport cards (and motherboard installed too!) 
parports out there with a very puny drive capability, and that $15 Newegg 
might be one of them since the poor chipset seems to have about 90% of the 
aftermarket.  IIRC, the chipset you don't want is made by NetMos.  It can't 
even drive an opt-isolator without booster buffers.  Generally, if the 
motherboard claims SuperIO, it will probably be ok.

We find this stuff out on the emc list because emc demands a good parport, 
particularly when using steppers on your mill/lathe.

-- 
Cheers, Gene
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