TIP: Click on subject to list as thread! ANSI
echo: apple
to: comp.sys.apple2
from: Steven Hirsch
date: 2009-02-25 07:36:52
subject: Re: Disk ][ controller PROM

sicklittlemonkey wrote:
> On Feb 25, 6:10 am, Steven Hirsch  wrote:
>> So these do not have a programmable equivalent?  To be clear: I
ask because I
>> want to verify that my programmer can read small bipolar PROMs.  The content
>> is really not the point.
>>
>> I'll just dig through spec sheets and match pins up the hard way if no one
>> knows offhand.
> 
> Please do check your spec sheets.

I should probably explain the entire picture here!  I purchased a couple of 
ProDEV DDT board kits at the time that Chuck went out of business.  For the 
past year, I've been struggling to get either of the IIGS or IIe boards to 
operate - with little success.  They will present the ROM-based monitor, but 
breakpoints are inoperative, as is the NMI pushbutton.

I have always had a standard EPROM programmer and an older PAL/PLD programmer 
and was able to verify that the EPROM and PAL were correctly blown.  Until 
this week, I have not had any means to check the little DIP package PROMs. 
When my eBay purchased Advin Pilot 143 programmer arrived, I read the PROMs 
and, unless the programmer is defective, all of them are programmed as a chip 
full of 0fh values.  This is not correct and would explain the misbehavior.

I was interested in reading a known-good PROM as a reality check, thus the 
questions about the A2 disk controller.

Before getting the tip to a cheap source, I lost patience and ordered some 
blank units at usurious prices (don't even ask...).  Hopefully I'll be able to 
program these and get the DDT cards operational.

I did drop Chuck a note, but I don't think he checks his e-mail very often and 
wouldn't expect him to remedy a problem discovered now on a kit purchased 3+ 
years ago.

Steve
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