Pine

Create the bootloader file

1. Clone ArduinoCore-samd
2. Go to folder /bootloaders/zero
3. (Option) Append Makefile line 66 for crystalless board with -DCRYSTALLESS

    CFLAGS_EXTRA=-D__SAMD21G18A__ -DBOARD_ID_$(BOARD_ID) -D$(SAM_BA_INTERFACES) -DCRYSTALLESS
   

4. (Optional) Edit board_definitions_arduino_zero.h line 26 to change product name

    #define STRING_PRODUCT "Pine"
   

5. (Optional) Edit sam_ba_usb.c line 156 to change manufacturer name

    #define STRING_MANUFACTURER "Hutscape"
   

6. Run make
7. Ensure files bootloaders/zero/samd21_sam_ba.bin and bootloaders/zero/samd21_sam_ba.hex are created

Burn the bootloader

1. Download and open SEGGER J-Flash Lite
2. Connect the J-Link SEGGER with SWD pins to the PCB
3. Choose the created bootloader data file samd21_sam_ba.bin
4. Click Program Device
5. Disconnect J-Link SEGGER and connect the PCB to the laptop
6. Double press the reset button to bring it into the bootloader mode
7. Query ls -al /dev/cu.usbmodem* to ensure the port is detected
8. Query arduino-cli board list | grep arduino to ensure the board is detected

     /dev/cu.usbmodem14101           Serial Port (USB) Arduino Zero (Native USB Port) arduino:samd:arduino_zero_native arduino:samd
   

9. Flash the blinky LED program with crystalless option

1. Arduino Core for SAMD21G to make the bootloader file
2. Download SEGGER J-Flash lite software
3. Tips and Tricks – Jumping from the Bootloader to the Application Code Cleanly
4. LCSC part for SAMD21G
5. How to burn Arduino Zero bootloader to an Atmel ATSAMD21G18-based custom dev board
6. SAMD21 Mini/Dev Breakout Hookup Guide
7. Adafruit Adalink
8. OpenOCD
9. ST Link
10. Pogo pin connector
11. How to Program SAMD Bootloaders by Adafruit
12. ARM Programming by SparkFun
13. J-Link model overview