How to set one pin to gpio function? Tx2-4GB

Dear all:

I want to know, how to set one pin to gpio function whit tx2-4gb board.

I echo 87 > /sys/class/gpio/export ,report error.

thanks .

hello 504566020,

it seems a duplicate issue, please check discussion thread Topic 1063903.

87 is NOT a valid GPIO number. Which pin/signal are you trying to set as a GPIO?