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DP83822I: LED_1 polarity

JAP
Intellectual 2410 points

Part Number: DP83822I

Hi,

Please see the snippet from DP83822I DS below.

"LED pins are automatically configured for the proper polarity based on the bootstrap configuration at power up or hardware reset. If an LED pin is resistively pulled low, the corresponding output will be configured as an active high driver. Conversely, if a given bootstrap input is resistively pulled high, the corresponding output will be configured as an active low driver."

When looking at LEDCFG2, polarity of LED_1 is active low. LED_1 has internally pull down, so shouldn't it be active high? Is the statement above referring to internal or external pull downs/pull ups?

Thanks!

Rgds,

Juha

  • 0
    TI__Mastermind 18425 points
    Hi Juha,

    Your interpretation is correct, that with a pull down resistor the pin would be configured as active high. But note that LED pins need parallel pull resistors in order to use LED functionality in a system. This would mean that the polarity of the LED pins now depends on the external resistor. The correct default polarity of the LED pins should reflect the strap.

    -Regards,
    Aniruddha