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MSP432 GPIO with High-Drive capability

Vyacheslav Prokopiy
Expert 1305 points
Other Parts Discussed in Thread: MSP430F5529

Hello!

In datasheet on MSP432P401 it's specified, that 4 outputs can drive current up to 20 mA.

But I didn't found any infomation about specific pins, which can perform this action.

Could someone help me find this info?

  • 0
    Guru 246840 points

    Where do you get the number four from?

    There is no maximum drive current for any single pin; the datasheet specifies current limits for a given maximum voltage drop. (See What is drive strength a measurement of?)

    As far as I know from MSP430 MCUs, the output drive strength selection (PxDS registers) should apply to all GPIO-capable pins, i.e., all Py.x pins.

    In theory, section 6.10 (Input/Output Schematics) should show how the PyDS.x register bit affects each output, but this appears to be missing from the current MSP432P401R datasheet. Have a look at some correct datasheet (e.g., that of the MSP430F5529) to see how this works; to summarize, all PyOUT.x and "from module" signals should be affected by it.

  • 0 in reply to Clemens Ladisch
    Guru 46710 points

    >There is no maximum drive current for any single pin
    In case of msp432 there is. I agree to Vyacheslav that 20mA support is mentioned in first page overview thou exact pins are not specified. My guess that mentioned 4 pins are hi-speed i2c pins.
    >In theory, section 6.10 (Input/Output Schematics) should show how the PyDS.x register bit affects each output
    I/O schematics usually does not show output driver circuit details, nor any other information that would allow to estimate output driver current handling capabilities

  • 0
    Guru 74080 points

    Vyacheslav,

    the four high-drive pins you are looking for are

    • P2.0
    • P2.1
    • P2.2
    • P2.3

    On the LaunchPad, the RGB LED uses three (P2.0/1/2) of those four pins. P2.3 is routed to one of the headers. You're right, this information is missing in the datasheet. I already complained about that and this will be changed. As you can read in the Technical Reference Manual, pins that do not support the high drive strength always read the PxDS-register as 0. So if you set P2.0/1/2/3 to high drive strength, these pins will be the only one that can be read back as 1. All others will be 0.

    Dennis

  • 0 in reply to Dennis Eichmann
    Intellectual 605 points

    So what is the regular drive capability?

  • 0 in reply to Shujen Chen
    Guru 74080 points
    If I remember correctly, there is no value given, only an output voltage vs. output current graph. Look at this graph and decide if the output voltage at a specific output current is OK for you.

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