How to use the BOOTSEL button

#1

Can someone explain how the RP2040 BOOTSEL button works?

On a regular microcontroller, you push the button before plugging it into the USB port, so when the microcontroller powers up, BOOTSEL is shorted.

But, on X2L the RP2040 is hardwired to the board and there is no way to “plug it in” with the button pressed. Do I plug the X2L to another computer while the button is pressed? Do I have to power down the X2L to use the BOOTSEL button?

Can Radxa provide more documentation on how to use onboard RP2024

#2

Hi friend

You only need to short press the BOOTSEL botton at anytime. It will reset the rp2040 and put it into BOOTSEL mode. Then in the J4125 OS, you can see the usb drive, and follow this doc for program RP2040

https://docs.radxa.com/en/x/x2l/software-development

we will update the docs later to make it more clear.

#3

Another way is to toggle J4125 GPIO to reset rp2040 and put it into BOOTSEL mode if you are running Linux on J4125:

ps@ps-palmshell:~$ cat usb.sh
#! /bin/bash

sudo gpioset gpiochip1 60=1
sudo gpioset gpiochip1 61=1

sleep 1

sudo gpioset gpiochip1 60=0
sudo gpioset gpiochip1 61=0
Resetting the RP2040
#4

Thanks for that info. I have V1.3 and both of those methods work.

So gpio 60 is for powering the RP2040 and gpio61 is for BOOTSEL. Good to know.

Do you have more info on how to get serial communication between the RP2040 and the Intel chip? This would be a much more useful GPIO tutorial than having a blinky tutorial.

I looked at the schematics and the RP2040 UART0 is connected to the IT8613 UART, but I don’t see any documentation on how to use it. More information would be greatly appreciated!