The jumpers allow the I/O (Inputs and Outputs) to be redirected for a different purpose. For example, there are no dedicated pins for the Infrared transmitter and receiver. Adding jumpers at the bottom of the jumper block allow the yellow LED and Push Button I/O to be used for IR communication. The Left side of the Jumper block are I/O from the Pico. The Right side is the optional hardware which can be connected. In the case of LEDs and Push Buttons, these devices remain connected to the I/O. The LED will report the signal out but the switch would typically not be used.
The Raspberry Pi Pico and the Pico Core have slightly different pinouts. This is reflected in the first 4 Jumper positions. On the RP Pico the GPIO 23 and ADC3 are used for different purposes and for this reason cannot be used for the Neopixel and Battery Voltage sensing. When using the RP Pico these first 2 jumpers should be removed. ADC2 can be used to sense the Battery Voltage or the Pot. This is selected using jumpers 3 or 4.
Typical Jumper Settings
IO_A and IO_B are used for the Aux Port and can be selected for Outputs (bLED, gLED) or Inputs (bPB, gPB). These two signals are also used as additional signals for the SPI and I2C ports. Four jumpers are used to determine the direction of these signals. Once set these signals will be present wherever the A and B signals appear on the ports.
The Chip Select (CS) for the general purpose SPI port can either be connected to the rLED or bLED lines.