I am evaluating building a replacement display for the AIM-65 that does
not use the DL1416. I have several modern options - a 20x1 LCD is
cheap enough, as are more modern 4-char ASCII LED displays. The interface
is somewhat trivial - the connector on the AIM-65 mainboard has enough
signals to talk to a 6520 PIA (since that's what is on the normal display
board to begin with). There are couple of angles to pursue...
I have successfully tested a Motorola 6821 in place of the Rockwell 6520
in a real AIM-65. Since I have a few 6520s and many 6821s, that's a win.
Either way, it's trivial to hang a display off of the 6502 bus without
a PIA in the way. I'm curious if anyone knows why they bothered to
put a 6520 on the display card? Did they want to keep the bus loading
to a small, known quantity? If so, then I'll consider that any ASCII
LED solution I come up with needs to have appropriate signal conditioning.
I can't see how a modern LCD display would load the bus any worse than
a 6520, so it might be worth the direct approach.
So... the hardware is no big deal. The software, though, could be lots
more work. I have real ROMs and ROM images. Are there any sources to
the AIM-65 ROMs that are in a state to be compiled back into working,
matching binaries? If I'm going to change the nature of the display,
the code will have to follow. If the code is changing, then there's
no reason I can't experiment with a multi-line display - I have a 20x4
VCD and a 20X4 LCD display already in hand. I think I can locate a
40x2 in my junk box, but at first, I'll probably ignore the right half
and if I used it, treat it like a 20x2.
Is there anyone out there who has done any real AIM-65 hacking? I can
start from zero if I have to, but if there's any preexisting work out
there, I'd like to see about starting ahead of zero.
-ethan
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Received on Wed Apr 17 2002 - 13:01:43 BST