HP9816 PAL16L8

[Paul Berger]

On 2019-06-11 6:17 a.m., Paul Birkel via cctalk wrote:
>> -----Original Message-----
>> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Chuck Guzis via cctalk
>> Sent: Tuesday, June 11, 2019 12:19 AM
>> To: Tony Duell via cctalk
>> Subject: Re: HP9816 PAL16L8
>>
>> On 6/10/19 8:44 PM, Tony Duell via cctalk wrote:
>>
>>> You can detect sequential logic in the PAL by :
>>>
>>> For each combination of inputs :
>>>     Read the outputs
>>>       Toggle an input (change from 0 to 1 and back again or vice versa)
>>>       Compare the outputs to what they were before -- if they have
>>> changed then there's a sequential function on that input
>>>       Check the next input
>>>    Check the next combination of inputs
>> For purely combinatorial PLDs, see my blog entry on the subject over at
>> vcfed.org; I did the work to clone a few PALs some years ago and
>> documented the process.
> http://www.vcfed.org/forum/entry.php?330-Cloning-a-PAL-HAL-Part-13
> http://www.vcfed.org/forum/entry.php?329-Cloning-a-HAL-PAL-Part-12-The-Trantor-T130B-memory-PAL
> http://www.vcfed.org/forum/entry.php?328-Cloning-a-HAL-PAL-Part-11
> http://www.vcfed.org/forum/entry.php?327-Cloning-a-HAL-PAL-Part-10
> http://www.vcfed.org/forum/entry.php?326-Cloning-a-HAL-PAL-Part-9
> http://www.vcfed.org/forum/entry.php?325-Cloning-a-PAL-HAL-Part-8
> http://www.vcfed.org/forum/entry.php?321-Cloning-a-PAL-HAL-(Part-7)
> http://www.vcfed.org/forum/entry.php?320-Cloning-a-PAL-HAL-(Part-6)
> http://www.vcfed.org/forum/entry.php?319-Cloning-a-PAL-HAL-(Part-5)
> http://www.vcfed.org/forum/entry.php?318-Cloning-a-PAL-HAL-(Part-4)
> http://www.vcfed.org/forum/entry.php?316-Cloning-a-PAL-HAL-(Part-3)
> http://www.vcfed.org/forum/entry.php?315-Cloning-a-PAL-HAL-(Part-2)
> http://www.vcfed.org/forum/entry.php?314-Cloning-a-PAL-HAL-(Part-1)
>
> A nice read.  When does the article/book get self-published :->?
>
> -----
> paul
>
The process documented above is essentially the process I started last 
night, but in my case I used a GPIO in my HP 9000-332 to cycle through 
the inputs and record the output.  It is very handy to have general 
purpose parallel I/O for purposes like this.  In this case the number of 
possible states is reduced as two of the inputs are permanently tied 
high.  I am well on my well to developing logic equations to feed into 
palasm to generate a new JEDEC file which I can then burn into a GAL and 
test to see if it is correct.

Paul.