CA v3 - PAS Direction detection

drummerian

100 W
Joined
Mar 13, 2012
Messages
131
Location
Leamington Spa, UK
I've done some googling but really struggling to find clear info on this topic.

I plan to use a 3 pin PAS for my CA v3 build, annoyingly any affordable torque sensors don't seem to currently ship to the UK and since I've had decent experience with PAS before I'll be using this for now.

The PAS I have I believe to be of the type where different length pulses are sent based on fwd or rev direction:
1718971058969.png
(image from here: Pedal Assist Systems - Learn)
There is a variant to this 1-wire sensor that pulses both with forwards and reverse rotation, but the pulse width changes between the two. For instance, forwards rotation might have a long HIGH state, and a short LOW state, while this is inverted when pedaling backwards. The control system must be programmed to discern based on relative pulse width if it is the forwards or reverse pedal direction and only respond accordingly. It also requires the detection of several pulses before it can positively identify forwards or reverse direction, so normally there would be a slightly longer delay before PAS power kicked in.

What isn't clear to me (despite the description of the sensor being from Grin's website), is whether the CAv3 can be setup to support this type of PAS. The guide I've read seems to be more about the types where you have a second wire for direction, or, no signal when backwards pedalling.

Any advice appreciated, thanks!
 
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