BOOSTXL-POSMGR: I want to use LAUNCHXL-F28379D and BOOSTXL-POSMGR to communicate with the encoder by BiSS-C

Try to narrow down the issue - if you probe the MA signal at the MCU does it toggle? Is the frequency correct?

Check the power/ground to the encoder. Make sure the power supply isn't current limiting - try supplying the power to the encoder through an external supply instead of the launchpad supply.

Hi Lori 

Thank you for the advice. I’ve probed the clock signal and attached a photo of it for reference. The clock frequency is correct at 5 MHz, but there’s a global frequency pattern that aligns with the program’s execution cycle—every 100 milliseconds, there’s an interruption.

I’ve checked the ground connection to the encoder, and it’s properly grounded. The encoder is also powered with an external supply rather than through the launchpad.

Despite these checks, I’m still not receiving any data—the BISDATA.structure.scdraw variable is constantly reading as 0.

Thanks again for your help!

Is the clock making it through the RS485 transceivers? It will be a differential signal on the encoder side.

Double check that the boosterpack is on site 2 of the launchpad and correctly connected.

TxeN should be low

Hi Lori, 

yes, the clock it making through the RS485 transceivers

also the Boosterpack is on site 2 and correctly connected, and TxeN it's low 

i think that i have probleme with CRC check, because i'm receiving data and CRC_Incorrect_counter increase 

attached is the data signal sent by the multiturn encoder (13 bits+12 bits)

Bentoura,

I found another post where a customer was using simulink that may help. If it doesn't I would suggest contacting simulink support. 

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1177339/tms320f280049c-posmgr-project-example-to-read-biss-c-encoder

Regards,

Lori