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CC3235MODSF: UART1 TX/RX on GP03/GP04

Part Number: CC3235MODSF
Other Parts Discussed in Thread: LAUNCHCC3235MOD, SYSCONFIG, CC3235SF, OPA4342

Dear Champs,

We tried to test UART echo  on LAUNCHCC3235MOD for all UART0/1 TX and RX but met no communication on GP03/GP04.

Other UART0/1 TX and RX are workable.

Is something wrong in below setting? 

sysconfig on uartecho_CC3235SF_LAUNCHXL_nortos_ccs example:

And the GP03/GP04 connection on LAUNCHCC3235MOD  (have removed J11 and J12)

But GP03 and GP04 still do not work.

If you have any suggestions, please feel free to let me know.

Thanks a lot.

  • Hi Janet,

    No. This cannot work. from two reasons:

    • There are ADC buffers at pins GPIO_03, GPIO_04 by op-amp OPA4342 (please see schematic for LaunchPad)
    • Pin 19 of booster pack connector is connected to GPIO_28 not a GPIO_04 (see DNP R59)

    Jan

  • Hi Janet,

    Jan is correct. That configuration would work on a custom board, but it will not work by default on the LaunchPad hardware.

    You can use the available DNP on the LaunchPad to bypass the op-amps. Please see the schematics and layout in the LaunchPad hardware design files: https://www.ti.com/product/CC3235MODS

    Best regards,

    Sarah

  • Dear Jan & Sarah,

    Thanks for your confirmation. This concern result from LaunchPad  hardware. I found it. 

    We use GP03/04 as UART1 TX and RX on the target board with confidence. 

    Thanks a lot.