Loading trinket m0 remotely from command line?

[chrisjx]

Using a trinket m0 to drive some LEDs. All works fine in the arduino IDE; I never have to press the reset buttons prior to loading code.

Now I'm trying to use bossac 1.9.1, but it seems it requires the physical button 2-press reset. avrdude did not. So imagine my surprise at this revelation. Sadly, this won't do for remote installations where I don't have physical access to the trinket.

I'm executing this:

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bossac -e -w -v -R --offset=0x2000 --port=/dev/ttyACM0 LED_Status_uC_rgb_neo_4.2.1.ino.bin

and unless I press the reset button twice, bossac does not see the trinket's USB port:

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No device found on /dev/ttyACM0

I tried some hacky/trickery like this in an attempt to remotely set it to loader mode:

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  if (Serial.available() > 0) {
    String command = Serial.readStringUntil('\n');

    if (command == "bloader") {
      // Trigger the bootloader
      // Sets a magic value and triggers a software reset
      *((uint32_t *)(0x20000000 + 0x000008)) = 0x50484352;
      NVIC_SystemReset();
    }
    ...

But that just resets/reboots the trinket.

This is kind of a deal breaker if there's no way to remotely update firmware.

Any tips appreciated,
Chris.

[chrisjx]

This seems to be working... on Raspi, bookworm

Log in to your default pi user.

Install bossa:

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sudo apt install bossa-cli

Create a file named... load_code.sh, and paste this code

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#!/bin/bash

# Define the target device and firmware file
DEVICE="/dev/ttyACM0"
FIRMWARE="myledcode.ino.bin"

# Step 1: Open the device at 1200 baud to trigger bootloader mode
echo "Triggering bootloader mode on $DEVICE..."
stty -F $DEVICE 1200

# Step 2: Wait for the device to reset and reappear
echo "Waiting for $DEVICE to reappear in bootloader mode..."
sleep 2  # Allow time for the device to enter bootloader mode

# Step 3: Check if device is back (it may briefly disappear and return as ttyACM0)
until [ -e "$DEVICE" ]; do
    sleep 1
done

# Step 4: Upload the firmware with bossac
echo "Uploading firmware to $DEVICE..."
bossac -e -w -v -R --offset=0x2000 --port=$DEVICE $FIRMWARE

# Step 5: Confirm the result
if [ $? -eq 0 ]; then
    echo "Firmware upload successful."
else
    echo "Firmware upload failed."
fi

Run chmod to make your code executable:

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chmod +x automate_bossac_upload.sh

Execute the code:

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./load_code.sh

The trick seems to be in the stty command opens the serial port at 1200 baud, which causes the Trinket M0 to reset into bootloader mode.

Next, I need to make sure I can get it to work on centos 8 stream.

Hope this helps someone else.

[chrisjx]

Just another tidbit... about deploying

When creating the code and compiling it, I just used the arduino IDE and loaded the appropriate libs for leds and the trinketm0. You'll need to round up those misc components up for your project as needed.

This is a good iterative setup to build your code; write it, compile & upload it, test, try again.

When you're ready to deploy/update the compiled code, go to the Sketch > Export Compiled Binary menu and if it is successful, you'll find the artifacts (.bin, .hex, etc.) under your arduino project folder (e.g., /Users/chris/Documents/Arduino). This you'll copy to where ever it needs to be.