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ZXnet http server: Note N00024: PBXGA Switch Settings

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Number: N00024
Created: 13 February 2009
Revised: 14 February 2009

This note describes the switch settings used on the PBXGA series of TGA graphics cards produced by Digital Equipment Corporation.

PBXGA Variants

   PBXGA-AA = ZXLp-E1   2MB   8-plane
   PBXGA-BA = ZXLp-E2   8MB  24-plane
   PBXGA-CA = ZXLp-E3  16MB  24-plane, 24-plane Z-buffer (stereo)

   Part numbers ending with "-xN" are the Windows NT model.
          

Switch settings

The four position switch selects the resolution and frequency used on initialization. The software can override these settings. Below are the switch settings as presented in the manual:
Switch location

   Up = Open = 1.  Down = Closed = 0.

    Switch    Switch   Pixel freq.   Resolution   Vertical
    value    1 2 3 4   (MHz)                      freq.  (Hz)
   --------+---------+-------------+------------+------------
       0     D D D D     130         1280x1024      72
       1     U D D D     119         1280x1024      66
       2     D U D D     108         1280x1024      60
       3     U U D D     104         1152x900       72

       4     D D U D      93         1152x900       66
       5     U D U D      75         1024x768       70
       6     D U U D      74         1024x768       72
       7     U U U D      69         1024x864       60

       8     D D D U      65         1024x768       60
       9     U D D U      50          800x600       72
      10     D U D U      40          800x600       60
      11     U U D U      32          640x480       72

      12     D D U U      25          640x480       60
      13     U D U U     135         1280x1024      75
      14     D U U U     110         1280x1024      60
      15     U U U U     Reserved

          

This information was obtained from http://antinode.info/dec/pbxga_settings.html.