• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 51 subscribers
  • Views 451 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CC2642R: UART current consuption doesn't go down when disabled

Randy Hellman
Prodigy 50 points

Part Number: CC2642R
Other Parts Discussed in Thread: SYSCONFIG

Hi, 

I'd like to be able to turn UART on and off depending on the state of the device. The device in idle consumes <2uA when UART is not enabled in sysconfig but once I enable it in sysconfig current goes to 20uA even though I haven't done UART_open. Can you please help me track what is happening to increase the current by 20uA just by selecting UART2 in sysconfig? I've been looking through  Power_init(); but haven't found it yet.

Thank you,

Randy 

  • 0
    TI__Guru**** 223917 points

    Hi Randy,

    The UART RX pin is configured as a pulled-down input pin when not in use.  This is done to prevent damage to the GPIO pin when the connected device is sending data without the UART module being prepared to receive it, however section 8.13.6.1 of the Datasheet does reflect that this will result in a typical 19 µA of current consumption.  If the RX pin is never used to receive data or if you are confident that this pin will not transition while UART is disabled then you can change the RX configuration to save power.

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Prodigy 50 points

    Ok, thank you. That definitely made a big difference but I'm still seeing an additional 1uA draw. If the UART2 is enabled in sysconfig and both pins a set as inputs with no-pull there is a 1uA increase compared to when no UART2 is enabled. 

  • 0 in reply to Randy Hellman
    TI__Guru**** 223917 points

    I'm glad to hear that there is an improvement in your applications current consumption.  I would attribute the additional 1 µA increase to leakage current through the input pins.  You could confirm this by leaving the DIO unconnected (floating) and in a tri-state condition.  This is partly discussed in Section 13.5 Unused I/O Pins of the TRM.

    Regards,
    Ryan