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MPaulHolmes · 02-07-2009, 12:20 PM

The new 2 wire throttle works really well, however...

The datasheet includes both the LM117 and LM317. It said it keeps 1.25v between Vadj and Vout (for the LM117 AND LM317!!!), but it actually keeps 2.0v between Vadj and Vout (for the 317). Ya, that would be good info to include in a datasheet. So, I chose resistors accordingly, for the 1.25v, which made my 0-5v input to the DC-DC converter around 0-6.3v! I had prepared for just such an emergency in the software, to shut down if the voltage was over 5v to the throttle input on the chip, however, in my debugging process, I was trying to wire the throttle input of the chip to ground during testing, but I wired a different pin (I think it was AVcc) to ground, which as they used to say on Ghost Busters, is a bad thing. Well, I need a new ATMega8, which is coming in the mail. Makes me mad! WAAAYYYYYYY DOWN DEEP! I need some new flame retardant clothing, cause I'm a steaming pile of flames and anger!

Well, either the datasheet was wrong about those lm317's or the lm317's I ordered from Ebay are a different type.

02-07-2009, 12:20 PM	#358 (permalink)
MPaulHolmes PaulH Join Date: Feb 2008 Location: Maricopa, AZ (sort of. Actually outside of town) Posts: 3,832 Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000 Thanks: 1,362 Thanked 1,202 Times in 765 Posts	The new 2 wire throttle works really well, however... The datasheet includes both the LM117 and LM317. It said it keeps 1.25v between Vadj and Vout (for the LM117 AND LM317!!!), but it actually keeps 2.0v between Vadj and Vout (for the 317). Ya, that would be good info to include in a datasheet. So, I chose resistors accordingly, for the 1.25v, which made my 0-5v input to the DC-DC converter around 0-6.3v! I had prepared for just such an emergency in the software, to shut down if the voltage was over 5v to the throttle input on the chip, however, in my debugging process, I was trying to wire the throttle input of the chip to ground during testing, but I wired a different pin (I think it was AVcc) to ground, which as they used to say on Ghost Busters, is a bad thing. Well, I need a new ATMega8, which is coming in the mail. Makes me mad! WAAAYYYYYYY DOWN DEEP! I need some new flame retardant clothing, cause I'm a steaming pile of flames and anger! Well, either the datasheet was wrong about those lm317's or the lm317's I ordered from Ebay are a different type. __________________ kits and boards Last edited by MPaulHolmes; 02-07-2009 at 12:31 PM..