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Old 11-08-2008, 01:55 AM   #264 (permalink)
trebuchet03
MechE
 
Join Date: Dec 2007
Location: Bay Area
Posts: 1,151

The Miata - '01 Mazda MX-5 Miata
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doh! Stickduino That's not the first time I've made that mistake :X

So yes, after staring at it long enough, it hit me that the arduino needs power

I've gotta debug my setup, it's quite messy - and, buggy

It won't always initialize - and when it does, only one character row (bottom) is showing up, and it's displaying repetitive garbage - looks like the duino is resetting. I don't have it hooked up to the obd port just yet.

When it fails to initialize, the hd44780 chip gets hot. Which also happens if I remove my external 12V supply (arduino still powered on over laptop) - BUT, when I do so, I get random pixel flashes on both rows of the LCD o.0



It's late, but I'm thinking it doesn't like having two grounds - 1 being the PC ground to run the arduino and the other being the 12V battery ground. In fact, I'm not entirely sure how I'm getting anything to display - if the three grounds on the LCD are reference voltages, the digital pins from the arduino don't have a "nice" current loop....

Walking away now - I'll save round 2 for tomorrow...
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