I just completed building a quad-copter, and I got everything configured and working using the Configurator CLI. However, once I disconnect the USB cable and try to boot from only the battery power coming from one of the ESCs it simply does not boot.
I have the power connected exactly as recommended in the Wiki page:
3 ESC voltage lines are cut, and 1 ESC voltage line is used to power the APM.
I am using the recommended ESCs (Turnigy Basic 25 A), so I do not think its an issue of cheap ESCs not supplying enough power. I checked all voltage lines on the APM using my DMM, and it all reads the correct 5V.
After searching some Arduino forums, I found that in order to boot from an external battery sometimes you need to tie the FTDI Rx and Tx together or pull the Rx pin to ground using a 10 K resistor. This is because the Rx pin reads in garbage without the USB connected so the bootloader never times out and doesn't get kicked off. So I tried to tie the Tx and Rx together and use a 10 K Ohm resistor to pull the Rx to ground. Neither method worked.
I was finally able to get the APM to boot after pulling the Rx pin directly to ground (no resistor used). It appeared to boot properly, but I was unable to control the motors via my RC transmitter. (I am able to control the motors fine with my RC transmitter with the USB plugged in.)
Any thoughts,
Gene
Replies
I am doubtfull that trying the other ESCs will have an effect, but I will certainly try it later today. I will also try to de-solder the SJ1 jumper and connect power directly from the battery (11.1V 3 cell).
Could this possibly be a bootloader issue since the APM boots once I pull the FTDI Rx pin to ground?