button_click_rpmsg.rst

Sending state of button using RPMSG

!!! info “Schematic” === “Pocket Beagle”

=== "BeagleBone Black / Beagle Bone Black Wireless"
    ![](images/led_button_beagle_bone_black.png)

Code

init_message_channel();

while : true {
    if : digital_read(P1_29) {
        send_message(1);
    }
    else {
        send_message(0);
    }
    delay(100);
}

• Following code works on PocketBeagle, to use on other boards, please change the pins accordingly.

Explaination

init_message_channel is needed to setup communication channel between ARM<->PRU. It only needs to be called once, before using RPMSG functions.

while : true loop runs endlessly, inside this, we check for value of header pin P1_29, if it reads HIGH, 1 is sent to the ARM core using send_message and if it is LOW, 0 is sent to ARM core using send_message. Then PRU waits for 100ms, and repeats the steps again and again.