AM6422: BISS Request cycle on sdk11

Alan Ismail

Part Number: AM6422
Other Parts Discussed in Thread: SYSCONFIG

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1359937/mcu-plus-sdk-am243x-biss-c-maximum-requiest-cycle/5194126?tisearch=e2e-sitesearch&keymatch=BISS%20maximum#

The solution to change biss_drv.c works well up to SDK9.2

pruicss_xchg->delay_40us = ((icssgclk*10)/1000000); change to 10us

With solution above, i am able to achieve BiSS request of 62.5us

Using the latest motor_control_sdk_am243x_11_00_00_06 , I ported biss_drv.c and biss_master.asm and make similar change. However it seem the solution above no longer effective. I can not achieve 62.5us request cycle with latest code from motor_control_sdk_am243x_11_00_00_06.

Is there any section that I can change to achieve 62.5us request cycle

Thank you

Alan I

3 months ago

0 Arnav Raj 3 months ago

TI__Prodigy 530 points

HI Alan,

can you send me the signal capture of BiSS-C RX and CLK lines?
Things I want to understand here is
1. What is BiSS-C CLK Freq
2. What's the cycle time with current configuration

Thanks
Arnav

0 Alan Ismail 3 months ago in reply to Arnav Raj

Intellectual 425 points

Hello Arnav

Thank you for the reply. I do not have access to the Signal capture setup this week.

I have found a mistake on my part , with the fix the BiSS-C is now able to acquire position in 62.5us but only with 8Mhz SPI clock.

Going back to BiSS Diagnostic, I found that the BiSS-C position acquisitions are always producing CRC Error with BISS clock of 5Mhz and 10Mhz using example from SDK11

Result with 5Mhz BISS-C clock - CRC failed

Encoder-1 Singleturn Angle: 44.914207458000, received safety crc:0x7ffe, calculated safety crc:0xc9c6, e_w:0x0, sign-of-life counter: 14