6502.org

Posted: **Sun Aug 13, 2006 9:55 am**

On my CBM8032 I have found two free sockets (24 pins) positioned in the row of 901465 ROMs. I assume they were intended for EPROMs! If yes it must at least at some time have been manufactured fitting EPROMs. Does anybody know anything about this? And even if no such EPROMs are known, what is the pinouts of these free sockets? I would then make an adapter to an existing EPROM.

Posted: **Sun Aug 13, 2006 5:45 pm**

There's a schematic here:
http://www.zimmers.net/anonftp/pub/cbm/ ... rs/pet/re/

If you just get a blank image save it and open in an image editing program, for some reason it didn't display properly online for me, but I was able to see it by doing that. Looks like all 2332 ROMS except for UD7 which is a 2316.

Posted: **Mon Aug 14, 2006 10:40 am**

blackadder wrote:

Looks like all 2332 ROMS except for UD7 which is a 2316.

FYI: the 23xx ROMs can be replaced by 25xx EPROMs.

Posted: **Mon Aug 14, 2006 11:52 am**

.and in addition there exists an adapter to make the 2332/2532 sockets accept a 2732 EPROM, see

http://www.marcospecialties.com/Itemdes ... 00&eq=&Tp=

Posted: **Mon Aug 14, 2006 4:54 pm**

There might be some differences in the chip selects

http://arcadearchive.org/pinball/sys80/

I'll have to look and see what the exact differences between the 2332, 2532, and 2732 are when I get some extra time..

Posted: **Wed Aug 16, 2006 8:35 am**

I think this is the definite answere:

Code: Select all

       2532 (and 2332)             2532 socket in              2732
       4kx8 EPROM.                 CBM8032                     4kx8 EPROM

       +--------------+            +--------------+            +--------------+
    A7 |1    +--+   24| VCC     A7 |1    +--+   24| +5 V    A7 |1    +--+   24| VCC
    A6 |2           23| A8      A6 |2           23| A8      A6 |2           23| A8 
    A5 |3           22| A9      A5 |3           22| A9      A5 |3           22| A9
    A4 |4           21| CE2     A4 |4           21| +5 V    A4 |4           21| A11
    A3 |5           20| /CE1    A3 |5           20| /SELx   A3 |5           20| /CE1
    A2 |6    2532   19| A10     A2 |6    2532   19| A10     A2 |6    2732   19| A10
    A1 |7           18| A11     A1 |7           18| A11     A1 |7           18| /CE2
    A0 |8           17| D7      A0 |8           17| D7      A0 |8           17| D7
    D0 |9           16| D6      D0 |9           16| D6      D0 |9           16| D6 
    D1 |10          15| D5      D1 |10          15| D5      D1 |10          15| D5
    D2 |11          14| D4      D2 |11          14| D4      D2 |11          14| D4
   GND |12          13| D3     GND |12          13| D3     GND |12          13| D3
       +--------------+            +--------------+            +--------------+

where /SELx is an output line from a 74154 address decoding chip being low for one combination of A15,A14,A13,A12, otherwise high.

Required adapter:

Code: Select all

      Socket          2732

      12              12 and 18
      18              21
      21              n.c.

Posted: **Sat Sep 02, 2006 9:40 am**

I finally made the adapter as

Code: Select all

      Socket          2732 

      18              21 
      20              18 and 20 
      21              n.c.

to avoid crossing over between the left and the right hand side of the socket. Works fine!

To get the "professional adapter"
http://www.elektor.de/Default.aspx?tabi ... 0759&PN=On
seems to be difficult. Anyone knows if they still are on the market. "Pin-ball" arcades seems to be out of stock! No more manifactured?

Posted: **Mon Sep 18, 2006 5:07 pm**

Mats wrote:

Anyone knows if they still are on the market. "Pin-ball" arcades seems to be out of stock! No more manifactured?

I think the 2532 eprom was discontinued long ago.

http://www.sayal.com/ has these in stock.

Or, send me a PM. I have a very spare 2532 eproms from pulls.

6502.org

Spare sockets CBM8032

Spare sockets CBM8032