Pin Description

PIN_BUTTON

-D PIN_BUTTON=0

The button should be attached to GPIO0 (boot). It is used to enter boot mode when powering the Backpack. Operationally it is used to turn on and off WiFi mode.

PIN_LED

-D PIN_LED=16

LED indicator pin. GPIO16 is used on most ELRS receivers.

PIN_MOSI, PIN_CLK, PIN_CS

-D PIN_MOSI=13 -D PIN_CLK=14 -D PIN_CS=15

GPIO13, 14, 15 are the hardware SPI pins of the ESP8285. Hardware SPI is not used by default on backpacks, but instead bit banging SPI has been implemented. This is to allow the use of any available pins. For example, a standard ELRS receiver has Tx, Rx, and Boot pins available. They may be used as SPI pins for many of the targets.