BEC switch on the RoverMux

[Thomas Roell]

Looking at the schmatics, especially JP1. It seems that I could short 2 & 3 even for a 5V BEC, correct ? In that case JP1 pin 1 would give me regulated 5V back at 300mA ? This way the 5v on JP1 pin 1 should be more stable, even if a servo draws a lot of current.

[Michael Shimniok]

The simple answer: If you have a 5V BEC, short 1&2, bypassing the LDO regulator. If you have a 5.5V-6V BEC, short 2&3.

Somewhat more complex answer: The ATtiny13A should run off of no more than 5.5V. If the BEC voltage is more than 5.5V it should be regulated down to 5V by shorting 2&3. If it's only 5V, you should short 1&2 so the BEC's 5V goes directly to the Tiny.

I'm testing whether it's possible to feed the regulator 5V. The dropout voltage is extremely low at the minimal current draw required by the ATtiny+'157 chips. But for now running in that mode is 'at your own risk'. :)  I am investigating use of a 3.3V regulator instead which eliminates all these issues as well as the BEC selector jumper, but didn't want to change too much in Rev 0.3.

[Thomas Roell]

A 3.3V change sounds intresting, but that's not what I was after. I was toying with the idea of simply hanging a 5V microcontroller onto the 5V output of the MPC1824.