I'm trying to design a circuit with an ESP32-Mini that connects to a CAN bus via an SN65HVD230. I've added an MCP2221A as a USB/UART interface to the ESP32 so that I can program the chip while on board. The whole board is mean to attach to a BMW stick shift that requires a 12v supply.
I've breadboarded the circuit with all the different components on breakout boards, and the breadboarded version seems to work fine. However the whole circuit together doesn't seem to work and I can't find the problem.
The MCP2221A is responsive. I'm able to send it commands via USB and see responses. I don't see any information on the UART lines for the ESP32. Additionally, if I add 12v the board seems to get warm (which doesn't seem good).
I've got 5v from USB. The MCP2221A wants 5v. I've got an MCP1700 linear regulator for 5v->3.3v. The ESP32 and the SN65HVD230 want 3.3v. I've also got an MPM3610 buck converter to step the 12v down to 3.3v.
Clearly there is a problem with the circuit I designed, but I can't see the problem. Can someone please help?
Here is the schematic I designed:
Here is the PCB design:
Any help would be greatly appreciated, and if there is more information I can post to help debug the issue please let me know.