02/07/2022 at 10:54 •
New controller is now in place after refactoring the Motori code and adding some HPGL commands including escape sequences for querying the input buffer size and free space. The escape sequences can be used by the app sending data to avoid overflowing the input buffer.
I had an issue with the pen up/down font panel button creeping up on me that took some time to resolve, a tantalum capacitor on the front panel PCB had started leaking. It was used for deboucing the switch signal, but had the oppsite effect when leaking - it caused the signal to bounce in odd ways instead. After replacing all four tantals on the board the swiches now performs flawlessly, this includes the jog buttons.
Remaining now is making some pen holders so that the pen change code can be verified.
Original controller. There is a large heatsink on the underside of the plotter for the stepper driver transistors.
The Pi Pico based controller in place, techonlogy has come a long way since the original was made!
01/19/2022 at 18:01 •
Jogging and pen/up down from the original control panel works pretty well - but the code still needs a bit of polishing. There are reset in and out signals I have to figure out how to put to work - and the red alert LED should be lit on error conditions such as bad HPGL code received?
Next up is a blanking plate for the big hole left where the serial and parallell ports were, now it will only be a small cutout for the micro USB. And I have to make some pen holders so that automatic pen selection can be verified.