[Mugenski]

Hey guys,

Just soldered up a voltage divider for my revo using the two extra wires I won't be using from the flexi connector (vcc and current). I am wondering since I used the wires from the connector and left the crimped ends on, can I ground my voltage divider to the flexi port or should I be running two separate ground lines to the PDB/battery - One from the divider and another from the port?

DMM shows continuity between the flexi port ground and the ESC grounds at about 2.5-3 ohms.

[nitromethane]

Yes, you can.

One thing that confuses me here is that you keep mentioning FlexiPort that has no analog input pins? You should connect your voltage sensor to the Sonar/Power port that is under the Servo outputs and right of the main port.

You can also read about configuring a voltage sensor here: https://librepilot.atlassian.net/wiki/display/LPDOC/Configure+a+Current-Voltage+sensor

[Mugenski]

My apologizes, yes I mean the power port. First OP/LP board, hard keeping track of these connectors at 3am 

Also I noticed this on the link you posted
"Voltage input, Any sensor can be used as long as the input voltage to Revo's Sensor Port pins does not exceed 3.3V. Higher values can damage board's CPU!"

While on this page http://opwiki.readthedocs.io/en/latest/user_manual/revo/revo.html on the power/sonar port is lists the voltage input pin 5v tolerant. I was hoping to be able to use this setup with 5s (3.7v) down the road. Which page is correct?

[nitromethane]

According to STM32F405 datasheet, most input pins can tolerate 5V without frying the chip, but the effective measurement range for the analog to digital converters is from 0 to 3,3V so putting 3,7V shouldn't burn your Revo, but the reading will be off as it will rach peek value at 3,3V.

p.s.: sleep is overrated

[f5soh]

Exactly, if you want to measure something you should not exceed 3.3V

Inputs are also protected using FIL5.
If you use a Revo Mini the inputs are not protected if i remember right...

[Mugenski]

I'm using the full revo and will make sure to modify my resistor setup if I switch to 5s packs. Would it be alright to go under 3v for the vbat sense? I'm thinking 1k and 5.6k resistor. That would net me 2.54v on 4s and 3.18 on 5s.

Also since I'm in revo expert territory I have one more question. I am looking to run Sbus and frsky telem on the revo. Both are inverted. As far as I can tell the revo only has one inverter on the main port. Is this correct?

[f5soh]

Divider looks fine.

Frskytelemetry is not supported currently, so no issues...

[Mugenski]

I should have specified I am running raceflight on this revo which does support frsky telem but due to my sbus being inverted as well I hooked that to the main port. I know I can uninvert the sbus signal on the xsr board but I haven't yet found a way to do that for the s.port telem.

I guess my option is to uninvert the Sbus on my xsr and run that through the flexi port then run the telem through the main port with the inverter?

[f5soh]

Maybe better ask in a Raceflight thread in RCG ?
You should have answers from people using Raceflight.

[Mugenski]

Will do. Thanks for your help

[TadyTheFish]

I think the 5V tolerance is ment for digital pins. Analog inputs use ADCs i think they don't like 5V
I didn't look at the datasheet of the ARM but i know that i was using a Teensy 3.2 board for a project. That board tolerates 5V on digital pins but not on the analog inputs.