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MSPM0L2228: Problem with abnormal power consumption of UART0 receiving data in L2228?

user6481287
Intellectual 970 points
Part Number: MSPM0L2228

Tool/software:

When L2228 communicates with 1FR5043, when L2228 is in low power mode, there is a situation where the receiving current is too large. Using uart0, IO uses PA0 and PA1. When receiving data, the current is approximately 1.3mA. Could you please tell me how to set the low power mode for the serial port? What is the approximate power consumption when the low-power serial port is operating? Is there a procedure available for conducting the test?

  • 0
    Guru 99605 points

    Is there a jumper connected on J8? If so, try removing it. 

    This jumper applies a pullup (2.2K) to PA1/UART0_RX. When driven low, this draws 3.3V/2200Ohm=1.5mA.

    A UART Rx line is (always) driven from the other end, so I think the pullup isn't (ever) needed.

  • 0 in reply to Bruce McKenney
    Intellectual 970 points

    PA0 has no pull-up resistor. May I ask if there are any test routines?

  • 0 in reply to Bruce McKenney
    Intellectual 970 points

    The register parameters are as shown in the following screenshot

  • 0 in reply to user6481287
    Guru 99605 points

    What platform are you using? Is it the Launchpad, or a custom board?

    PA0 (UART0_TX) needs a pullup resistor, since it can't drive high (Open Drain). Moreover, it needs to be external, since PA0 (ODIO in general) lacks an internal pullup.

    I was referring to PA1 (UART0_RX). As long as something is connected to it, it does not require a pullup, since the other end is driving it. If there are times when it operates with the other end disconnected, a pullup (also external, since PA1 is also ODIO) is probably a good idea, but it should be fairly weak (20k maybe?) to avoid the symptom you described.

    What sort of test routines do you have in mind? It seems like you have a test case. The worst case is probably having the other send all-0x00 bytes.

  • 0 in reply to Bruce McKenney
    Intellectual 970 points

    Both Launchpad and custom board have been tested, and the phenomenon is the same. What is desired is a routine for testing the low-power data reception of the serial port. Our program tests have been abnormal all the time.

  • 0 in reply to user6481287
    Guru 99605 points

    The TI Launchpad examples are here:

    https://dev.ti.com/tirex/explore/node?node=A__ABvATzSBKGw7HunA5.8.FQ__MSPM0-SDK__a3PaaoK__LATEST

    The "DriverLib" examples are generally simpler and so easier to experiment with.

    Can you show a schematic of your custom board? When you use the Launchpad, is the J8 (PA1 pullup) jumper installed? [On my Rev-E1 Launchpad this is actually J13.]

  • 0 in reply to Bruce McKenney
    Intellectual 970 points

    After testing, the power consumption was still relatively high. This project was used for the ultrasonic gas meter L2228 to receive data from FR5043, communicating once per second.

    1. Is UART0 a low-power serial port?

    2. When performing interrupt reception, is the interrupt service routine running in RUN mode?

    When entering the data reception, there is approximately a high level of about 7mS. What causes it to be above 2mA?

    FR5043 transmits 33 bytes of data once per second and receives an instantaneous current of 1.2mA. Is this receiving current normal?

    The following figure shows the collected current.