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rusefi / alphax-2chan

24 pin / 2 channel ECU
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Document all pullup/pulldown lines #39

Closed rusefillc closed 2 years ago

rusefillc commented 2 years ago

We need to document what state of pullup/pulldown GPIO lines does what

image

for instance, CRANK_PULLUP set to 0 is it VR while CRANK_PULLUP set to 1 is Hall?

I believe we need explicit readable text maybe table right on schematics PDF

andreika-git commented 2 years ago

We have two separate "pieces of knowledge" here: 1) CRANK_PULLUP set to 1 means that pull-up resistor is enabled, while set to 0 means the pull-up is disabled. 2) Hall mode needs pull-up resistor enabled while VR mode doesn't.

So technically speaking, both VR and hall are always "enabled". And CRANK_PULLUP doesn't switch between them, it just helps them to work correctly.

rusefillc commented 2 years ago

@andreika-git at the moment we have no user facing summary of what are the five options doing.

@andreika-git at the moment I do not know which value enables what user experience myself.

it looks like for crank 0=VR and 1=Hall from user perspective

need same 0=X and 1=Y explanation for all other options

like thermistors, 0="Use build-in pull-up" and 1="No pull-up" or the other way around?

mck1117 commented 2 years ago 
2. Hall mode needs pull-up resistor enabled while VR mode doesn't.

And part 2b is that for some hall crank sensors, it doesn't actually matter whether you have a pullup or not. My LS cam/crank sensors output a nice sharp 12v square wave, no pullup required.