HP48 - InVision48 projector

[Han]

(02-18-2014 12:57 PM)Joe Horn Wrote:  

(02-17-2014 07:57 PM)Han Wrote:  Was there never an back-ward compatible adapter for the HP48? I know they had such adapters for wire transfer. I take it these did not have proper LCD lines.

As Raymond mentioned, the LCD panel came with a 48 cable, whose calculator end was shaped like a RAM card, which you plugged directly into the card slot. The 48SX used some of the pins in its card slots for display information, which the 48 cable sent to the LCD panel.

IIRC, the 48GX does not have the display info on those pins, so the panel cannot be used with a GX. But I also seem to remember that the GX's card slot #1 has different pin information than slot #2... so maybe the panel can be used in slot #1 of the GX. I do know for sure that it can't be used in a GX's slot #2, which used the former display lines for bank-switching multi-port RAM cards.

Card slot 1 is indeed different. In fact, on the GX, card slot 1 is identical (I think) to the card slots on the HP48SX. Card slot 2 on the GX had the display lines replaced with address lines connected to a multiplexer which handled bank switching. Anyway, the card slot interface for the HP48 version of the overhead display was what prompted my question... alas no one seems to have one on hand, then?