Nekota said:
The contrast probably needs to be adjusted. The pot to make that adjustment is small and took several different tools before I found something that moved the adjustment. You should be able to make the screen go to black squares from the no contrast.
Thanks - that's probably it (the screen shows full green, no black at all when on), but I can't find a pot on it for the life of me.
The screen looks very similar to the Adafruit unit, but I can't find anything that looks like a pot on it on the front/sides. I can't see anything on the back, either, but that's harder to see now that the display is sandwiched to the LeafCAN board.
This is the display I bought off eBay:
HD44780 1602 16x2 Yellow Screen Backlight Black Character LCM LCD Display Module
I only see 2 holes on the back that might be used for pots if you look at the pics - they are 2 pin-holes near the backlight power pins... one of those aren't it, are they? Desoldering the display is going to be a pain - how do you guys test the contrast without soldering/de-soldering repeatedly if the pot is on the back?
EDIT: Some googling reveals that I probably have to put a 10k pot on PIN-3 / VO of the LCD screen.
Looking at the board/schematic, PIN-3 of the screen goes to R3 (10k resistor) / C11 (2.2uf cap) which are not populated - I guess I'll have to solder in my own 10k pot?
Oh wait - is the pot on the LeafCAN board - the shiny metal thing with a philips head? Sure looks like a pot and is wired up to PIN-3 of the LCD. So what's up with the missing R3/C11? That must be for Arduino control of constrast?
Barbouri said:
Ground to OBD2 pin 4 Chassis Ground
+12 Volt to OBD2 pin 16 Constant power or (pin 8 Switched power)
EV CAN-L to OBD2 pin 12 EV CAN-L
EV CAN-H to OBD2 pin 13 EV CAN-H
The EV CAN is located on the OBD2 discretionary pins and is not used in many vehicles.
Use the 2x3 ISP header with your programmer.
Greg C.
Perfect, thanks Greg!