Re: [Paparazzi-devel] LisaM wiring question

[Piotr Esden-Tempski]

Hi,

On Jun 18, 2011, at 10:45 AM, David Conger wrote:

> Hi World,
> 
> May I ask a favor? 
> 
> I have wired my Lisa/M and hoped maybe I could get a review before I attempt 
> to power it this way. 
> 
> If wiring will work I'll gladly offer it to the Wiki as an example. I've 
> tried to follow advice given in the past for wiring. 
From how I see it it should work, not having the ground of the BEC connected 
may be bit sketchy, but adding it will create a ground loop. I am not sure 
which setup is the safest here. The resistors on the vertical board should 
protect the stm32 from any reverse current from the servo though. :)
> 
> Question. Is the resistor required on each PPM out pin? I want to remove the 
> extra pins by removing the daughter board and put only 1 row of pins on the 
> end for only PPM. Will i have to also somehow get the resistor there as well? 

The resistor is not a life and death requirement. I added them to protect the 
gates of the STM32, as I realized already in Lisa/L that sometimes shabby 
servos like to do strange things to their PPM input lines and manage to fry the 
STM32. After addition of the resistors on Lisa/L V1.1 this issue was gone that 
is why I carried it over to Lisa/M.

As you probably can see there is not very much space on Lisa/M ... but I add 
the move of the resistors from the vertical board to the mainboard as todo for 
the next revision of the board, when that happens. :)

Cheers Esden