I’ve been working on a custom board for my SimpleFOC project and I think I’m about ready to order it. However the last time I ordered this design it didn’t fully function as intended. I’m hoping that I have fixed the issues with the design but I wanted to get a second opinion. The main issue was that the STM32 was not communicating properly with the AS5600 chip over I2C. I think the issue had to due with the I2C pull up resistors. I copied the schematic from a known working breakout board in the hope of fixing the issue. Otherwise the STM32 was able to run the DRV8311 in open loop mode without any problems. I’ve also added breakouts for the UART pins to make troubleshooting easier. My questions for you. Thanks in advance.
Does the AS5600 circuit look correct? This was my main issue last time
Am I missing anything on the UART circuit? This will be used with an FTDI adapter
Does the AS5600 require one time programming before operation? I don’t think so but I’m not sure
Hi, nice work.
For the tracks between the driver and the 3 pin connector, i suggest you increase the width to reduce resistance on those high current tracks.
Geometry might be tricky but simple fan out shape seems to work.
It does not. And your 4k7 is in spec for I2C, I expect it to work.
For your driver power traces you could beef them up a bit as mentioned already.
For the MCU, the decoupling capacitors should be placed around the MCU one near to each VCC pin of the MCU. It will probably work as it is, but it’s not good this way.
Hi @Rikky
Thanks for the feedback. I’ll have to add the pull up on the next version. I’m guessing this is to make sure the pin doesn’t go low on its own. I also had a crystal previously and removed it. I’m going for minimal parts and found that it doesn’t make a big difference if I have it or not.
Hello @Vivishka
Thanks for the feedback. The max current draw on the motor is only 100ma(0.2mm traces in air), its very small. I guess I hadn’t considered asymmetric traces before. Is there a convenient plugin available to make this easier?
Thanks all for the replies. I managed to order the boards before any of the tariff fun came down. The board is working exactly how I want it to (for now…). Definitely need to remember breaking out UART from now on.
