2013/9/10 Mark Webb-Johnson <mark@webb-johnson.net>

That is a neat idea, and I've seen some battery-backup circuits work this way.

Thank you. As a bonus, this will also prevent polarity inversion.

The circuit comes down to 1xLP2992 for 3.3V power, 2xSN65HVD235 for CAN, 1xMCU(3.3V), DB9 & USB connectors, ICSP pins (for emergency), expansion pins (arranged for optional bluetooth module), and a few passives. That is neat.

I'm a bit paranoid, so I would add a TVS diode and a fuse, and two ferrite filters on the supply input, but none of them are strictly necessary...

Now, what would be truly amazing is if we could fit an SD-CARD in this,

I was going to ask that too, but since the goal was to reduce the costs, I just asked for the expansion headers! :)

Anything else?

I still prefer the ARM over the PIC, especially if you are going for the SD car slot! :) MBED FAT libraries are awesome.

SDFileSystem sd(p5, p6, p7, p8, "sd");

...

int main() {

FILE *fp = fopen("/sd/sdtest.txt", "w");

fprintf(fp, "12345678");

fclose(fp);

}

Regards