BLHeli is an aftermarket firmware developed by Steffen Skaug for SiLabs-based ESCs (XP-7A, XP-12A, etc.) which is intended specifically for use with the Blade mCP X. It adds a number of specific features for the including built-in support for the mCP X's PWM throttle signal, a built-in governor, and firmware for brushless tails. BLHeli is licensed under the GPL v3. The code is available on github.
The firmware ships with governor mode set to Tx by default. This means the ESC takes its governor target RPM from the throttle setting on the transmitter. In order to start up the motor a slightly-non-intuitive arming sequence is followed:
- Turn throttle hold on on the transmitter.
- Plug in the helicopter battery.
- Allow the 3-in-1 and ESC to initialize. The 3-in-1 will show steady blue and the ESC will play 3 ascending tones when they are ready.
- Turn throttle hold off. The ESC will play a low tone.
- Turn throttle hold back on. The ESC will play a high tone. It is now armed and ready to fly.
- To spin up the motor turn throttle hold off.