Flow Breakout Initialization

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Sailorjoe
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Joined: Thu Mar 22, 2018 5:30 am

Flow Breakout Initialization

Post by Sailorjoe » Thu May 17, 2018 12:24 am

I've been using the Flow Breakout board for an FRC (FIRST Robotics Competition) robot design. We are only using the PMW3901 motion sensor in a fixed height above the ground; we aren't using the distance sensor. We had some early issues with readings, and during troubleshooting I noticed that the initialization code for Breakout is slightly different that what is used on the Flow Deck for the Crazyflie. Since the data sheet for the PMW3901 is quite limited, I can't tell if the differences are consequential or not, nor which version is optimal for the Breakout board. I've attached a word document showing the differences. The column on the left is copied from the Arduino library for the PMW3901 on github/bitcraze. The column on the right is copied from the Crazyflie-firmware library at github crazyflie-firmware/src/drivers/src/pmw3901.c. I've highlighted the differences in yellow (I hope it shows up on your copy).

Can anyone explain the differences, and whether they are significant to our use case? Thanks for your attention to this.
Attachments
PMW3901Init.doc
Comparing PMW3901 Init codes
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tobias
Bitcraze
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Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Flow Breakout Initialization

Post by tobias » Fri May 18, 2018 7:10 am

Arnaud who has best knowledge about this is on vacation and will be back end of next week.

It is a bit problematic to collaborate with "closed" companies when we are open. Basically you need an NDA to get the details. I suggest you send an email to Pixart, maybe they are willing to help.

To summarize, the Arduino driver seems to have some flaws, hopefully together we can iron them out :D.

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