Image Map Image Map
Page 3 of 3 FirstFirst 123
Results 21 to 22 of 22

Thread: CBM 8032 Character Display Problem

  1. #21

    Default

    Hi Andy,

    I'm from Luxembourg in the middle of Europe.

    Andreas

  2. #22
    Join Date
    Feb 2009
    Location
    Southern California, USA
    Posts
    2,321

    Default

    Quote Originally Posted by Andreas Zock View Post
    I bought four 2532 EPROMs today because they are pin compatible with 2332 ROMs.
    But would a 2716 also work, because the pin layout is a bit different?
    Andreas,
    Good question. In the 8032 PET, as a character generator, the chip selects in the ROM/EPROM should always be enabled (low). So pin 18 is tied to CHR Option in the CRT Controller which will be low in this application and pin 20 is tied to ground. In the 4K byte 2532 pin 18 is not a chip select but address line A11 input. So as long as the information is programmed into the lower 2K of the EPROM, it will work fine as the A11 input will always be low.

    In the 2K byte 2716 both pins 18 and 20 are 'chip enables' so being held low will also work fine.

    EDIT: By a coincidence of pinouts, a 2732 EPROM can be used in this socket if the data is programmed into the upper 2K of the EPROM! See pin 21 (A11) of the 2732.
    Last edited by dave_m; September 14th, 2017 at 10:55 AM. Reason: added 2732 info

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •