Oak

🌳 An outdoor LoRa-GPS tracker with an E-Ink display 🔑

power 18650
wireless LoRa,
sensor GPS, E-Ink
mcu SAMD21G18
bom items 82
bom cost USD $78.93
vendors 6
completed July 2022

Upload Arduino Zero bootloader

bootloader j-link edu mini difficult

Upload bootloader Arduino Zero with J-Link Edu Mini

setup

Details

Pin connections

SWD Connector pin SWD Pin name SAMD21G
1 Vtref not connected
2 SWDIO PA31
3 GND GND
4 SWDCLK PA30
9 GND GND
10 RESET RESET

SWD Pin connections on the PCB

Create the bootloader file

  1. Clone ArduinoCore-samd
  2. Go to folder /bootloaders/zero
  3. (Optional) 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 "Oak"
  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 Edu Mini 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 Edu Mini 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

Schematic

Wire up the hardware accordingly

setup

References

  1. Arduino Core for SAMD21G to make the bootloader file
  2. Download SEGGER J-Flash lite software