From RoadsideThoughts ...
A Bit of Vectrex History
 
Introduction
Programmer's
Guide
 
The RUM
 
Mine Storm
Fortress of
Narzod
 
Dark Tower
   
Sitemap
     
 

Vectrex Programmer's Guide

Memory Map



The 68A09 can address memory between $0000 to $FFFF (65Kb).

The ports of the 6522 programmable interface adapter (PIA) have been mapped into the memory space beginning at $D000. A PIA port is selected by the setting of address bits 3 to 0 (the least significant address byte). The setting of address bits 11 to 4 (the two middle bytes) are ignored. As a result, $D12F, $D6AF or $DFFF is the same as $D00F - only bits 15 to 11 (which must be to a hex D) and bits 3 to 0 matter.


The Vectrex memory has been mapped as follows:

Address Range   Description
 
  $0000 - $7FFF   (32kb)     Reserved for game ROM   (read only)
 
  $C800 - $CBFF   (1kb)     Static RAM   (read or write)
        $C800 - $C87F   (128b)         Reserved for RUM
        $C880 - $CBFF   (896b)         Reserved for game logic
 
  $Dxx0 - $DxxF   (16b)     The Programmable Interface Adapter   (read or write)
 
  $E000 - $EFFF   (4kb)     Reserved for Mine Storm   (read only)
 
  $F000 - $FFFF   (4kb)     Reserved for the RUM   (read only)


The 68A09 has reserved the highest 16 bytes of memory for its various vectors:

Address Range   Description
 
  $FFF0 - $FFF1     Reserved
 
  $FFF2 - $FFF3     Vector to the Software Interrupt #3 (SWI3) Handler
 
  $FFF4 - $FFF5     Vector to the Software Interrupt #2 (SWI2) Handler
 
  $FFF6 - $FFF7     Vector to the Fast Interrupt Request (FIRQ) Handler
 
  $FFF8 - $FFF9     Vector to the Maskable Interrupt (IRQ) Handler
 
  $FFFA - $FFFB     Vector to the Software Interrupt (SWI) Handler
 
  $FFFC - $FFFD     Vector to the Non-Maskable Interrupt (NMI) Handler
 
  $FFFE - $FFFF     Reset Vector


    
 
 
 

Home
Page
Sitemap Privacy
Statement
Terms
of Use
Feedback

 
 

Please keep in mind that we can not guarantee the accuracy or timeliness of the information on this website, so use with care. We encourage you to double-check the information that is critical to you.

If you've found an error or have additional information that you would like to share, please don't hesitate to write. Click here to contact us.

Copyright 2016
All Rights Reserved
This page was last modified: 12 Jan 2017
By John Hall