Current Bootloader Status

Svn containing all bootloader work: ​http://gauss.bu.edu/redmine/projects/arduino-zero/repository/libs/show/zero_bootloader

To-Do (11/30/17)

• Implement any CRC checking?
• Reading is really slow, but that may be normal
• Bootloader ID scheme: resistors connected to each uC (5 10k resistors in series seem to work well)
  • Right now, from UC0 to UC3, resistance reads: 800,600,400,200
  • This can be changed if necessary
• read bootloader proposal below

Necessary documentation!!

• what in the bootloader needs to change if you add more uC slots w/different voltages

Procedure to upload a new bootloader

• Plug the ATMEL programmer into your computer and the Sparkfun board (which should have an 8 pin programming connector next to the reset button).
  • The programming cable should be plugged in under SAM on the programmer.
  • The other end should be plugged into the board with the red wire closer to the tx led (with the 6 pin connector unconnected).
• Select "Atmel-ICE" from the Tools menu, under Programmer.
• The Sparkfun board needs to be powered, either through a micro usb or an external power supply if it's plugged into the motherboard.
  • Now both a red and green light should be lit on the ATMEL programmer.
• Download the arduino IDE if you haven't already (from arduino.cc)
• Under the Tools menu and Board Manager, download the "Arduino SAMD Boards (32-bits ARM Cortex-M0+)" package if you haven't already
• Under the Tools menu, select "Arduino/Genuino Zero (Native USB Port)" for Board, and whichever port has "Arduino/Genuino Zero (Native USB Port)" in parenthesis next to it.
• Download the "zero" folder from the svn link above (it's located within the trunk folder).
• Use the make command to make the bootloader (Something about a define to indicate Bootloader number?)
• Move the zero folder into the arduino bootloader directory, replacing the folder currently named zero.
  • The bootloader directory can be found by pressing "Burn Bootloader" in the Tools menu of the Arduino IDE (Don't worry, doing this will only burn the default arduino bootloader to the board).
• Once you've replaced the old zero folder with the svn folder, press "burn bootloader" again to upload our bootloader to the board.

Procedure to upload a new arduino sketch

• Using a micro-usb is the same as it always has been, just plug it into a uC and press upload in the arduino IDE
  • The Sparkfun boards sometimes have issues. If the sketch is not uploading, after pressing upload, double click the reset button.

• To upload to the raspberry pi:
  • Under the Sketch menu "Export Compiled Binary". This binary will be in the folder you can open with "Show Sketch Folder" also in the Sketch menu.
  • Download SamD_funcs_base64.py and program_with_bootloader.py to your rasberry pi.
  • Make sure the rasberry pi is connected to the motherboard with a DB9 cable.
  • Run program_with_bootloader.py followed by the uC number to be uploaded to, followed by the binary file (eg. "python program_with_bootloader.py 1 Blink.ino.bin" for uploading Blink.ino to board 1 in linux)

Sketch upload communication proposal

• If using the raspberry pi, the following procedure is proposed:
  • The raspberry pi first sends some reset signal to be interpreted by a serial library (maybe '~')
    • This will jump to the start of the bootloader
    • The arduino should automatically go to a safe state in the bootloader
  • A different signal is sent to move to bootloader commands for ONLY one arduino ('$1P' for Program the 1st uC) (also '$1E' for echo to 2nd uC, etc)
  • Then, the sketch can be programmed
  • Once it's programmed, a command is sent to get the uC back to the safe part of the bootloader (probably '~' again)
  • When all programming is finished, a signal is sent to wake up all the uC's ('$4W' for Wake all 4 uC's)
  • The user should not interrupt the raspberry pi, or cycle power, while an upload is occuring

Final Interfacing goals

• End users don't need to touch the Motherboard or any of the boards on it unless something breaks
• If they want to change anything, they only need to edit an arduino sketch and upload it
• uCs shouldn't have to be moved around (reprogramming them is easier)
• The uCs can be differentiated by the resistance between pin 8 and ground
  • both the bootloader and arduino sketch can read the value of this pin
• Code on the raspberry pi allows a user to pick a board (1-4) to upload to, and code to upload
• The raspberry pi will handle communicating with the uCs to upload a sketch