Analog / Digital Input for Tesla SDU drop-in board V8

[Basti123]

Hello everyone,
I'm currently converting my VW Beetle with a Tesla Small Drive Unit. I have even successfully swapped the boards without destroying anything.
But now i run into some issues while wireing the Molex connector. I'm afraid of breaking something.

For example the acceleration signal or the break signal. These are 5V Signals going through a RC filter and then directly to the microcontroller. And the pin 8 & 9 are not 5V tolerant.

Same for the 12V signals for FORW_IN or START. They go through a 1k / 1k voltage divider. That left more than 6V at the microcontroller pin? That can´t be right...right?

I also have the feeling, that the scematic is not correct with the resistor values. Is there a new version of the scematic?

Unfortunately I can't post any pictures of the scematic. I hope you know what i´m talking about

Kind regards from Munich
Sebastian

[johu]

Hi and welcome!
Indeed the values in the schematic are incorrect!
https://github.com/jsphuebner/Tesla-Fro ... /master/V8

In the BOM it is 4k7 and 1k5. So 3.3V at 14V input.

You are allowed to feed more than 3.3V into a non-tolerant pin as long as it is current limited to 5mA off the top of my head. The ESD diodes direct it to the 3v3 rail. Again the schematic value is not correct, those are 10k not 1k

The latest V9 board corrects this by using a 1k/1k divider instead.

That said, if you have a pre-V9 board you must limit throttle voltage with an external series resistor for safety reasons: viewtopic.php?t=5075

[Basti123]

Many thanks for the quick reply. It all makes much more sense now.