Re: SX kernal ROM

From: MagerValp (MagerValp_at_Goth.Org)
Date: 1998-09-30 11:37:23

>>>>> "Marko" == =?ISO-8859-1?Q?Marko M=E4kel=E4?= <ISO-8859-1> writes:

MV> My SX motherboard (PNO 251102 REV A) has a 28 pin socket for the
MV> kernal ROM, which is a 2654 EPROM. The schematics lists UD3 as
MV> being either a 2364 or a 2564.

Marko> What is a 2564?

8k*8 EPROM.

Marko> Is it pin-compatible with the 2764?

No. You can find the pinouts in the Chip Directory, e g
It's almost pin compatible with the 2364. It's easy to make a 28-pin
socket that can take either a 2564 or a 2364 without jumpers or
rewiring, and this is what CBM did with the SX-64 socket. The 24-pin
JiffyDOS kernal worked just fine.

MV> I'm asking because I can't seem to find the correct pinout for the
MV> 2364.

Marko> Try the C64 schematic diagrams from And if you do
Marko> so, please let me know, what exact pins are wrong in the 256kB
Marko> memory expansion docs.

Found it:
    (slightly to the left and below the centre of the picture)
    (middle right)

both list pin 21 as A12. The expansion docs lists it as /CS2.

    ___          .     .  .         .       . +  .         .      o   
  _|___|_   +   .  +     .     +         .   .     +    + Per Olofsson
    o-o    .      .     .   o         +             MagerValp@Goth.Org
     -       +            +    .
This message was sent through the cbm-hackers mailing list.
To unsubscribe: echo unsubscribe | mail

Archive generated by hypermail 2.1.1.