4
JP1 is used to determine the source of its power. If the
jumper is between the center pin and the pin closest to the
top of the display, then the power is derived from the radio.
If the jumper is between the center pin and the bottom of the
display, then the power is derived from an external power
supply.
JP2 is a four pin jumper block and is used as the connector
for attaching a debug pod to allow the programmer to debug
the display.
JP3 is used for setting the microprocessor to boot mode to
allow the user to load the firmware in case the display gets
bricked. If the jumper is between the center pin and the pin
closest to the four pin jumper, then the microprocessor is in
boot mode. If the jumper is between the center pin and the
bottom of the display, then the microprocessor is in normal
mode.
JP4 is used for enabling the backlight for P1 - P4 and the
power key. If the jumper is between the middle pin and the
pin closest to JP1 then the backlight for those keys are
always on. If the jumper is absent or the jumper is between
the center pin and the pin closest to JP2, then the backlight
for those keys are always off. The backlight for those keys
take a significant amount of power.