CCS/LAUNCHXL-CC26X2R1: LAUNCHXL-CC26X2R1

Hi Kiran,

Please see this previous e2e post regarding 3-Wire SPI: https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz/f/156/t/803998

Unfortunately the 3-Wire half-duplex SPI mode isn't available in hardware on this device. The 3-wire mode here refers to the user controlling the CS line manually. You may be able to write your own driver or bit-bang a solution using the Sensor Controller on the device to achieve half-duplex 3-Wire SPI mode.

Please see Chapter 22 of the CC13x2 CC26x2 TRM for available SPI modes: https://www.ti.com/lit/ug/swcu185d/swcu185d.pdf

Regards,

Daniel

Thanks, Daniel.

I tried your suggestion of controlling CS line manually. But it didn't work.

I will try again and see if I can make it work. At present I am using both the SPI buses and got two SPI devices (4-wire) to work on PCB. I have one device on each SPI bus.

But I have 5 SPI devices (4-wire) and need to make them work. I want to have one SPI bus  0 for on board serial flash and 2nd SPI bus 1 for 4 sensors (4-wire SPI).

So far only flash on SPI0 and one sensor is working on SPI1.

Thanks

Kiran

Kiran,

What I meant is that in the SPI 3-Wire mode shown in SysConfig in your screenshot above is a SPI mode where CLK, MISO, and MOSI are controlled by the SPI peripheral and the CS/SS pin is controlled by the user manually in their code. Typically this would be a GPIO you configure and toggle high and low as needed.

In the case of using multiple devices on a single SPI bus you would use 3-Wire mode and add GPIO(s) as needed to toggle CS high and low for each device on the bus.

This is different from the 3-Wire half-duplex SPI mode your 2nd screenshot where MOSI and MISO are shared on a single line.

I hope that helps to clarify.

Regards,

Daniel