MMOS servo motor direct drive steering wheel simulator control board

Experience the joy of direct-drive steering wheel at a low cost. This set of boards is a Riding isolation board, but it has been successfully used on Delta AB1021 driver and 31309 motor.
Based on the open source Riding isolation board of pkintel, a big guy from B station, it has been modified many times according to my own use. It should be the finished Ultra version.
 
Circuit introduction video
test video
G-force seat video
 
This is the original circuit of the big guy. There are several problems in use:
1. An external 12V power supply is required
2. Using LM358 RC low-pass filter to convert PWM to analog, the speed is not fast and there is interference
3. The button IO is not fully brought out, and the SPI expansion IO part is lacking, which is not convenient for connecting gears and Hub
4. The weighing amplifier seems to have a poor effect, and the AD620 chip is re-adopted to realize 3-way weighing signal amplification
5. Replace the Type C interface, but it increases the difficulty of welding (smile
6. I hope to simplify the connection and reduce the size of the board
 
. For the above problems, the following solutions are adopted:
1. Directly use USB 5V power supply, isolate and boost 12V
2. Use GP8501 to realize dual-channel PWM to analog quantity
3. nRF51822 Bluetooth chip SPI expansion IO, wireless expansion, very good for use on steering wheels
4. Weighing amplifier AD620 is in another project, and has not been tested on the board (mainly because the stainless steel parts of the weighing pedal are too expensive)
5. Type C is indeed a little more difficult to solder
6. Add SPI IO expansion of MCP23S17, which can expand 16 buttons wired
7. Draw an adapter board according to Delta driver. In another project, there is no need to solder wires to SCSI 50pin (good news for clumsy people)
 
TODO:
1. Since GP8501 can only output 5V analog quantity, adjust the gain and test the influence of direct drive torque (a dual GP8101 version has been added, you can choose as needed)
2. Test MCP23S17
3. Test whether a single Type-C power supply can drive the entire board