Thanks to a bunch of disk images that must have been made by Ruud (thanks!) , I came across some demo programs for a hi-res board for the PET. Then I remembered that I had some vague and confusing notes about its use, which I got when we had one on loan at the school's computer club (assuming the boards to be the same). Putting 1 and 1 together, the programs seemed to match the notes, and so with the help from the notes, and the realisation that the notes implied there was a PIA in the mix, I started to implement an emulation in VICE. First I got it working as a weird memory expansion, then with the help from the #vice-dev irc channel, I hooked it into graphics output. It was nearly working on the first try :-)  So now this is in the svn version of VICE, and here is a patch you can probably apply to 2.2 (which has just been released). Here are my notes: The DWW hires board has a PIA at address 60200 = $EB28 It seems that in the demo programs, the BASIC versions like to POKE in 60200, where the machine language programs use $EB00. 60200 Port A or DDR A $EBx0 1 0 \ 2 1 - RAM block at $EC00 (0-7) 4 2 / 8 3 charrom 0 = off 1 = on 16 4 hires 0 = on 1 = off 32 5 extra charrom 0 = on 60201 Control Register A: bit #3 (worth 4) controls if 60200 $EBx1 accesses the Data Direction Register A (0) or Port A (1). 60202 Port B or DDR B $EBx2 0 = RAM is visible from $9000 - $AFFF 1 = RAM is bank-switched in blocks of 1 K in $EC00 - $EFFF [Control Register B is never mentioned, so putting 1 in this address would access the DDR, creating an output line, which after RESET is default 0...] Typical initialisation sequence: poke 60201,0 poke 60200,255 (all outputs) poke 60201,4 poke 60200,24 or 25 (16 + 8 + 1) Demo programs on disk PBE-110A, 110B, 111A, and 111B. These disks can be found inside http://vintagecomputer.net/commodore/64/baltissen/Pbe.zip (PBE = PET Benelux Exchange, the Dutch PET user group) The memory mapping is a bit strange. It seems each 1 K block contains the pixeldata for 1 bit-line of each text line. This is probably so that the addressing of the RAM can borrow part of the addressing logic/signals of the text screen. (The screen addressing cycles through 0-39, then increases the line (= byte offset) which is fetched from the character ROM; for the graphics, the screen position selects the byte in a KB and the char ROM offset selects which KB of graphics RAM). My notes say: to set a pixel: RE = INT(Y/8): LY = Y - 8*RE (or Y AND 7) BY = INT(X/8): BI = X - 8*BY (or X AND 7) when memory mapped to $9000: L = 36864 + 1024 * LY + 40 * RE + BY POKE L, PEEK(L) OR 2^BI when memory mapped to $EC00: POKE 60200,LY + 40 (or 8?) L = 60416 + RE * 40 + BY POKE L, PEEK(L) OR 2^BI  Dubbel-W bord, designed by Ben de Winter and Pieter Wolvekamp  http://vintagecomputer.net/commodore/64/baltissen/Pbe.zip  http://www.falu.nl/~rhialto/dww-patch  http://www.falu.nl/~rhialto/dww1.png  http://www.falu.nl/~rhialto/dww2.png  http://www.falu.nl/~rhialto/dww3.png -Olaf. -- ___ Olaf 'Rhialto' Seibert -- You author it, and I'll reader it. \X/ rhialto/at/xs4all.nl -- Cetero censeo "authored" delendum esse. Message was sent through the cbm-hackers mailing listReceived on 2009-12-22 22:00:03
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