Pololu/A-Star bootloader on Arduino Leonardo

By | 20. October 2014

The 32U4 based Arduino-Micros and Leonardos do an 8 second delay for the bootloader. This is way too long to work with a esc – the esc will give up saying: no valid servo signal detected – security shutdown.

Pololu’s A-Star family is using a different bootloader that boots into the application in ~1s and can be put into bootloader mode manually by quickly pressing reset twice (in less than 0.75s).

As is expected, you can easily burn the A-Star bootloader to a Leonardo:

  • download the bootloader from here
  • get the fuse settings from here : low=0xff, high=0xd0, extended=0xc8
  • burn it

As the bootloader supports the standard upload protocol, no additional software is required.

Nevertheless, getting the board into upload mode is way fiddlier as usual: in boot mode, the Leo registers as an A-Star serial device on one COM port, after booting it switches to “Leonardo serial” on another. I had to press boot-mode before triggering the compile and then again before the actual upload …

Running Windows 8.1 as OS on my dev machine, i had to install the pololu driver (from here) manually to make the os enumerate the COM-port.

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