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First Battery Com Capture

A project log for DJI FPV Investigations

Things I've learned about the DJI FPV quadcopter.

Duane DegnDuane Degn 03/28/2021 at 05:334 Comments

Based on my experience with the DJI RoboMaster S1's battery, I had assumed the FPV drone also communicated with the battery over I2C. I was wrong about this. The data transfer looks like CAN bus.

My logic analyzer doesn't read CAN packets so I'll need to figure out a way of reading this data. I thought I'd share this information in case any of you are interested.

Edit (April 1, 2021): Thanks to Andrew Young who informed me my logic analyzer was capable of decoding CAN. This is the exported text of the CAN data:

Time [s],Packet,Type,Identifier,Control,Data,CRC,ACK
2.111320843750000,0,DATA,0x554,0xE,0xEF 0xEE 0x93 0xE9 0x7B 0xAE 0x8D 0xBF,,
2.114893812500000,1,DATA,0x138,0xF,,,
2.126467750000000,2,DATA,0x153EFBE9,0xE,0x67 0xFE 0xD6 0x15 0xE9,,
2.310771906250000,3,DATA,0x554,0xE,0xEF 0xEE 0x93 0xE9 0x7B 0xAE 0x8D 0xBF,,
2.314893750000000,4,DATA,0x138,0xF,,,
2.515036843750000,5,DATA,0x138,0xF,,,

Discussions

Abir wrote 09/13/2021 at 13:36 point

Hi, did you tried to made decoy communication to enable the use of any battery?

Thanks for the detailed posts!

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John wrote 04/08/2021 at 15:01 point

Great job! You did it over pins on battery connector or pcb testpoints? Can't seem to find pinout of this drone/battery yet

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Andrew Young wrote 04/01/2021 at 15:51 point

The Saleae Logic software should be capable of decoding CAN - I have the same version and CAN is available as an analyser in the list.

https://support.saleae.com/protocol-analyzers/supported-protocols

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Duane Degn wrote 04/02/2021 at 02:32 point

WOW! I can't believe I never noticed those other protocol options. I always just used asynchronous serial, I2C or SPI.

I added the decoded data to the log.

Thank you for letting me know about the other protocols.

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