View Single Post
Old 09-29-2015, 07:31 PM   #2114 (permalink)
thingstodo
Master EcoModder
 
Join Date: Sep 2010
Location: Saskatoon, canada
Posts: 1,479

ChargE (not yet running) - '92 Mazda MX6 LX
90 day: 33.89 mpg (US)

Ford Prefect - '18 Ford F150 XLT XTR
Thanks: 746
Thanked 543 Times in 438 Posts
Quote:
Originally Posted by e*clipse View Post
Ok, on my silly little problem... ( Motor Control? I can't get the debugger to talk..)

There is a pullup resistor from MCLR to Vdd. (yes, it should be there)

I measured the Vdrop across it, and it's 2.083V, when plugged into the ICD2. If not plugged in, there's no Vdrop.

The resistor measures 4.53KOhms. That's solidly in the 1K > 10K range Microchip specs.
The ICD2 may be trying to perform a reset and it's not quite making it there? If the ICD2 can only sink 0.63 milliamps (2.86V / 4.53K) .. that seems unreasonably low. It should be able to sink at least 10 mA which would be *MORE* than adequate.

The ICD2 is a bit older .. what if it presents a load to the MCLR which is higher (at 0.63 mA) than the controller expects? Is it reasonable to put a 1K6 in parallel with the 4K5? (works out to 1K2 by my math). The voltage on MCLR should rise to around 4.25V ...

... but then again ... it's not MY hardware we're talking about modding
  Reply With Quote
The Following User Says Thank You to thingstodo For This Useful Post:
e*clipse (09-29-2015)