RJ Riememsnider
TVWBB Pro
I am interested in using a larger display on my heatermeter so that i can display all 4 probe temps at the same time. Longer term it might be nice to use the extra real estate to be able enter probe types without using the serial interface. According to Bryan Mayland:
So for starters to not affect anything existing, I would like to add an additional mode for 4 line, how does HM control what display mode it is using? There is a selector for 2 line and all the big number modes. How does this work, is there a variable that contains the mode then based off the value an if/then/else writes different data to the display?
Known working displays:
PINHD-1X16 from Mouser or Digikey
HD44780 based 20x4 line displays
*Please note that to connect the display directly to the HM4 header, you must get an LCD with the connector below the display(pin1 on the left and pin16 on the right when viewed from the top). Some LCDs only have one connector above the display, to use this you would need a ribbon cable or relocate the 4 way button on the HM4.
The display code is in hmcore.cpp updateDisplay() function. The easiest thing to do without adding a ton of progmem usage would be to just have it loop through the probes and use the existing formatting functions instead of just outputting the one probeIndex. I know a lot of 4 line displays are also 20 characters wide but having different formats for 16 vs 20 character widths means big changes all over the place to support it so keep that in mind.
So for starters to not affect anything existing, I would like to add an additional mode for 4 line, how does HM control what display mode it is using? There is a selector for 2 line and all the big number modes. How does this work, is there a variable that contains the mode then based off the value an if/then/else writes different data to the display?
Known working displays:
PINHD-1X16 from Mouser or Digikey
HD44780 based 20x4 line displays
*Please note that to connect the display directly to the HM4 header, you must get an LCD with the connector below the display(pin1 on the left and pin16 on the right when viewed from the top). Some LCDs only have one connector above the display, to use this you would need a ribbon cable or relocate the 4 way button on the HM4.
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