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ben239955_stm1_stmicro
Visitor II
July 5, 2005
Question

GPIO pin current

  • July 5, 2005
  • 1 reply
  • 640 views
Posted on July 05, 2005 at 17:10

GPIO pin current

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    ben239955_stm1_stmicroAuthor
    Visitor II
    July 5, 2005
    Posted on July 05, 2005 at 17:10

    I have a question about the maximum current sink capability of the GPIO pins on the STR71x series.

    According to the datasheet, when a pin is assigned to push-pull output mode, it can source either 8mA (high current pin) or 4mA (standard current pin) with a 0.8v drop below the V33 rail, or it can sink 4mA/8mA with a 0.4v rise above GND.

    My question is this: What is the maximum safe current that these pins can source or sink, regardless of the voltage drop?

    For example, is it possible to sink 10mA from a high current pin, with perhaps a 0.8v drop?

    The datasheet does not seem to specifiy a maximum current that can be sourced/sunk by the pins in output mode.

    I want to be able to drive an optocoupler diode from the UART TX pins through a 164 ohm resistor in order to achieve maximum speed from the optocoupler.

    Please advise if this is feasible.

    Best regards,

    Ben Edwards

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