Apple II+ 80 card emulation

[misterblack1]

This might be a long-shot, but would be possible to emulate the 80 column card for Apple II/II+ machines? (Over VGA of course)

It would possibly be pretty nice for the II/II+ owners out there to be able to get that nice razor sharp text for those machines.

[dkgrizzly]

This is planned, I just haven't gotten around to it yet. I wanted to do a lowlevel emulation of a videx compatible card and run the original ROMs from one, but due to the way most of those cards map the text buffer I don't think that a direct emulation will be possible. My next thought is to implement the same control characters and a simple "terminal" card firmware that just passes the raw character data over to the RP2040 to handle. This should be doable, I just have to implement a FIFO and character handler to parse the control characters (and only run the character handler while in vblank, or when there are no scanline buffers available to fill). The 6502 code should be quite small, other than the required input routine for lowercase.

[dkgrizzly]

I managed to implement the RP2040 side of 80 columns for II/II+ and need to write the 6502 firmware now to finish it. Has most (all?) of the Videx control characters implemented on the RP2040 side, the 6502 side just has to stuff bytes into the FIFO at $C0nA, reading back that same address to get the FIFO fill level ($00 = empty / overflowed, $FF = full). $C0n8 and $C0n9 are now the Clear / Set write registers for the 80column soft-switch. I'll try to smash together some 6502 code this week.

[Verault]

Just curious, how is the progress on the 80col Videx emulation support? Is this still in the works?