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Original question:

RTOS/CC1310: why can't enable weak pull up on uart rx pin?

CC1310: Setup UART RX pin with External Pull-Up

TheRLB
Prodigy 50 points
Part Number: CC1310

Tool/software:

Hi,

I am currently using a CC1310 for a battery powered project. The device spends most of its time in Standby mode and occasionally wakes up to transmit data or communicates with another device using UART.

On my custom PCB which uses the CC1310 i have configured the RX pin with a PULLUP Resistor as part of a Level shifter circuit as the other device operates on 5V. 

The issue i am currently experiencing is that before going to Standby i call the "UART_close()" and this makes the RX pin drift which causes a voltage drop across the PULLUP Resistor.

Is there a way to make the RX pin stay at HIGH (3.3V) after closing the UART driver. I have experienced issues if i try to enter standby mode with UART driver open so i close it before going to standby.

I also found an another post (link) regarding a similar issue but unfortunately the provided solution link is not functional anymore.

Greetings,
RLB

  • 0
    TI__Genius 17955 points

    Hi RLB,

    This should be the fixed link for the thread you were looking for: https://e2e.ti.com/support/wireless-connectivity/bluetooth-group/bluetooth/f/bluetooth-forum/679794/cc2640-uart-rx-pull-up-available

    You can also refer to Section 19 of SWCU117 (CC13x0, CC26x0 SimpleLink Wireless MCU Technical Reference Manual): https://www.ti.com/lit/swcu117

    Hopefully this resolves your issue.

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 50 points

    Hi Zack,

    I modified the UART driver file according to the post from Siri. I did not change the driver files in the SDK but copied the required files to my project but Unfortunately the changes have no effect.
    I made sure to use "#include <UART.h>" instead of "#include <ti/drivers/UART.h>" in the files where i use the UART driver.
    Is there something else i am missing.

    I also want to include all the driver files which are required to build my project locally so that if i were to send this project to someone they can compile it without needing to install the CC1310 SDK. Is there maybe a guide detailing how to achieve this?

    Greetings,
    RLB

  • 0
    Prodigy 50 points

    Hi,

    So i was able to setup my project to be able to use a project specific SDK so its easy to work in a Team. This is useful as i modified the UART driver so that everyone doesn't have to manually adjust it in their individual SDKs.

    If someone else wants to do the same, they can follow these steps:

    1. Goto Window → Preferences → Code Composer Studio → Products

    2. Add the path to your SDK and click refresh. CCS will search the directory for SDKs and list them under discovered products. (If you have other SDK installations and you want to make sure that CCS uses the correct one you can uncheck their path under "Product discovery path")

    3. Now you can still use includes like "#include "ti/drivers/I2C.h" and it will point to the correct path of the SDK that you included in step 2

    4. Important: If you are using TI-RTOS clean and rebuild your project as well as the TI-RTOS project otherwise you will get error  "#1965: cannot open source file"

    Hopefully this helps someone resolve their issue.

    Greetings,
    RLB