CC3235MODSF: UART1 TX/RX on GP03/GP04

Janet Shen

Expert 7795 points

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.

over 5 years ago

0 Jan D over 5 years ago

Guru 80275 points

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

0 Sarah P over 5 years ago in reply to Jan D

TI__Mastermind 38980 points

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

0 Janet Shen over 5 years ago in reply to Sarah P

TI__Expert 7795 points

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.

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CC3235MODSF: UART1 TX/RX on GP03/GP04