Other Parts Discussed in Thread: MOTORWARE, DRV8301, TMDSCNCD28069MISO
I have another thread on the software part of this:
e2e.ti.com/.../2216265
"DRV8301-69M-KIT: Running 2 SPI slaves in Motorware labs SPI implementation"
...but I think there is a hardware related problem too
If you want to connect 2 (C2000) SPI slave devices to one master, you need to put the inactive SOMI pin in high impedance mode.
However, the DRV8301-69M-KIT uses a ISO7241A digital isolator. As each of the pins has a fixed direction, I wonder if the IND-OUTD channel can be switched to a high impedance input...
I think using 2 DRV8301-69M-KIT slaves is not possible from a hardware perspective...
I checked for SPI-A SOMI, and I can use 3 GPIO, 3, 17 and 55.
GPIO-3 goes to DRV8301 as PWM-BL, GPIO-17 goes to the digital isolator and can not be intercepted and GPIO-55:
- is connected on the controlcard DIMM100 (F2806XISOCONTROLCARDR0_TMDSCNCD28069MISO.3SCH.pdf)
- is not connected on the driver board DIMM100
So I plan to solder a small wire to the pin70 of the DIMM100 to make GPIO-55 accessible and to have direct access to SPI-A SOMI to be able to set in high impedance mode.
I will keep you infomed of my progress. I hope I don't blow my board...
My question : can somebody confirm that I can not put the ISO7241A digital isolator output pin in a high impedance state ?
Best regards,
Tomas