User Manual

Running bossac on the command line

If you are using the Arduino IDE, this step is not required. But sometimes you want to read/write custom binary files,

say for loading CircuitPython or your own code. We recommend using bossac v 1.7.0 (or greater), which has been

tested. The Arduino branch is most recommended (https://adafru.it/vQb).

You can download the latest builds here. (https://adafru.it/s1B) The mingw32 version is for Windows, apple-darwin for

Mac OSX and various linux options for Linux. Once downloaded, extract the files from the zip and open the command

line to the directory with bossac .

With bossac version 1.9 or later, you must give an --offset parameter on the command line to specify where to start

writing the firmware in flash memory. This parameter was added in bossac 1.8.0 with a default of 0x2000 , but starting

in 1.9, the default offset was changed to 0x0000 , which is not what you want in most cases. If you omit the argument

for bossac 1.9 or later, you will probably see a "Verify Failed" error from bossac. Remember to change the option for -

p or --port to match the port on your Mac.

Replace the filename below with the name of your downloaded

.bin

: it will vary based on your board!

Using bossac Versions 1.7.0, 1.8

There is no --offset parameter available. Use a command line like this:

bossac -p=/dev/cu.usbmodem14301 -e -w -v -R adafruit-circuitpython-

boardname

version

.bin

With bossac versions 1.9 or later, you must use the --offset parameter on the command line, and it must have

the correct value for your board.

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