Re: Cinematronics BPROM alternatives

Thanx Ed, in my first statement, I meant that the F14 bprom
code does fit easily into xc9536. It maybe takes up only
15% of it. What I meant was that I'm wondering if there is
another smaller capacity and cheaper xPLD that would be a
better fit. I tried to fit the code into an ATF22V10CQ
which is cheap and small (This is what I used for the five
32x8 parts) but it would hold less than half of the data
table. The smallest parallel EEPROM is 2kx8 which is
overkill. I can get the xc9536 in a tiny 10mm square
package and reprogram it in-circuit and it's also much
faster than the EEPROM which is important when replacing a
BPROM. It's a working solution but I was hoping for a
smaller and cheaper device. The CCPU board that I'm testing
with is running on CAT28C16A flash EEPROMs for the game code
instead of 2716s and it's also running the EE-SPLD
replacements for the five 74S288 (32x8) BPROMs. I'd like to
test the F14 replacement but I have to build a chip adapter
first. I'm ordering a batch of the new PCBs for the 32x8
replacements today and should have them in-hand in two
weeks.

----- Original Message Follows -----
From: Ed Henciak <ehenciak@yahoo.com>
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Cinematronics BPROM alternatives
Date: Fri, 02 Oct 2009 04:04:02 -0400

>William Boucher wrote:
>>
>> I have also designed a replacement for the larger BPROM
>> (74S287 256 x 4) located at F14. For a first effort, it
>> is based on a Xilinx XC9536. I couldn't get all of the
>> data to fit into a cheaper SPLD but I'm open to
>> suggestions if someone has a smaller cheaper chip in mind
> for the job. I still have to build a socket adapter to
>> try it. For now, the design is done and the code is
>> written in VHDL but I haven't tried it in a running
>>board yet.

> How close to fitting this chip into an XC9536 (area
> wise)? If you are really close, you might want to play
> with a few of the settings to optimize for area. It
> seems like thr 36 should be good enough for what amounts
> to 4, 8 input logic functions. I could try running this
 thru a "better" synthesis tool for you if you'd like.
> (again, this assumes you are around 10% over the logic
>in the device.
>
>Ed
>
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Received on Fri Oct 2 10:05:38 2009