Mini Cheetah Controller Port

Because of the chip shortage, one day I was looking through my bin of ICs I’ve accumulated over the years and came across a stack of 20 DRV8323’s I’d ordered for a class project years ago. This was before I was familiar with Ben’s motor controller implementation and so I accidentally ordered the hardware configured version (he uses the SPI configured ones as does Austin). Similarly I was unaware that he used the F446RE and so I had ordered a handful of F303K8T6’s (per Austin’s recommendation).

I decided during this chip shortage where I cannot buy new DRV8323’s or F446’s (except stealing them from Nucleos which is $$$$$) I could port Ben’s latest motor control firmware to the F303 and use the hardware configured DRV chip in the process.

Much datasheet browsing later and I had laid out a new 2 layer version of his board in Eagle, choosing components based on what was in stock and what I had stashed away.

The main component changes are: the use of the F303, the hardware DRV chip, a different CAN transceiver, and different CAN connectors.

A short 3pcb order later and I had the boards in hand. Because the DRV footprint is fairly unpleasant to solder, I decided to order a stencil for the first time. It was incredibly painless and well worth the extra $10 or so.

I assembled 2 copies of the board so I could compare impedances to ensure I soldered them correctly (or at least messed up the same way twice…) but held off on assembling the whole batch until I had verified the layout.

I did a quick power supply test and was happy to see that the 3v3 LED turned on. This let me know that the DRVs buck converter was working (generates 5V), as well as my linear regulator (5V->3.3V). And no shorts.

I was able to program the F303 and get serial working, as well as check the encoder’s functionality. Then Battlebots responsibilities took over and I had to shelf this project for a bit. Now that I’m back, I plan on testing the FETs, the current shunts/amplifiers, and then hopefully get Ben’s Mini Cheetah firmware in Cube reconfigured and working for the F303.