HP97 The journey begins

[teenix]

I managed to try out the printer without actually connecting the printer, just to see how the output is going to look like. I had to fool the HP microcode into believing that the print carriage was home when it asked, because there was no physical carriage just yet.

The image shows the calculator just being turned on with 0.00 on the display and pressing PRx.

The scope trace clearly shows the data that controls the head elements giving the required pixels for the print-out. The characters have the italic style and they look reversed because of the right to left movement of the print head. The right side of the image shows the pulse width modulation of the head signals, so that part of the hardware is functioning as well.

Next, I'll have to proceed with the actual printer, but I have to wait until the latest circuit boards arrive, hopefully by early next week.

cheers

Tony