Tomato Pie MSPM0G3507 Development Board

Preface:
  I've been preparing for this year's electronics design competition recently, and my teacher and I designed this MSPM0G3507 microcontroller development board. We've already produced a small batch for the college's electronics design competition training, and after about two months of use, it feels great, so I'm sharing it here. Because it's a TI microcontroller, I used TI's signature red solder mask, hence the name "Tomato Pie."
Design Concept:
MSPM0G3507 Minimum System
  The circuit of the MSPM0G3507 minimum system is mainly based on the official TI development board LP-MSPM0G3507, including reset and BSL buttons, SWD debug interface, ODIO pull-up selection, crystal oscillator, and decoupling capacitors. A 40MHz active crystal oscillator was used, ensuring a stable clock frequency and saving a pin. At the time of designing the circuit, only the 48-pin MSPM0G3507SPTR chip was available, so I used a 48-pin chip for the design; and at that time, JLCPCB hadn't provided the device symbol and package (which they do now), so I drew one myself. Doesn't it look better than the official one? (Escape)
Power Supply and Protection:
  The Tomato Pie development board can be powered via a Type-C interface. A linear regulator steps down the 5V to 3.3V for the microcontroller. ESD diodes are added to the USB data port and the 5V and 3.3V power supplies. The 5V and 3.3V are also led out to pin header expansion interfaces for external output or internal input power. Both power supplies are equipped with resettable fuses and reverse connection protection diodes.
Peripheral Modules:
  The Tomato Pie development board also includes commonly used peripheral modules according to the functions I needed in the electronics design competition:

USB to Serial :
A CH340N chip converts USB data from the Type-C port to serial data, directly connecting to the microcontroller's UART0, so communication with the computer only requires a single Type-C cable;
RGB LEDs :
RGB LEDs are connected to three PWM-enabled pins on the microcontroller, allowing for mixing any color or direct GPIO control of the three LEDs;
Buttons:
The development board has five user buttons arranged in a top, bottom, left, right, and center layout for easy UI menu switching, etc. One end of the button is grounded, and the other end is connected in series with a small resistor to the microcontroller's I/O port to prevent short circuits caused by pressing the button when the microcontroller is outputting from that pin. When using the button, the microcontroller input needs to be configured as a pull-up, and software debouncing needs to be implemented. I think
rotary
encoders are very convenient for interaction, so I put one directly on this development board (which also makes the whole board bigger). The encoder button is the same as the user button mentioned above, with one end grounded and the other end connected in series with a resistor to the microcontroller. The encoder's AB channels have pull-up resistors and an RC low-pass filter to achieve hardware debouncing, so that rotation counting can be performed in the program by using GPIO interrupts.
Serial screen interfaces
are common in electronic design competitions, so the UART2 on the Tomato Pie development board is reserved for serial screens. For the serial port screen, two power supply methods were designed: internal and external. For small serial port screens, due to low power consumption, a jumper cap can be used to short-circuit J3, using the internal 5V to directly power the screen. For large serial port screens, due to high power consumption, internal power supply may cause system instability. In this case, J3 can be disconnected, and a 5V power supply can be connected to the external power supply interface to power the screen. The PCB and SMT of
  the Tomato Pie development board were produced in small batches at JLCPCB. All components used in the schematic support SMT. Currently, a 4-layer board version is being used. A 2-layer PCB version is also available in the project. If costs are saved, a 2-layer board could be used; theoretically, the performance difference wouldn't be significant. I previously wrote a test
routine
  for the Tomato Pie development board, implementing functions such as RGB LED rainbow gradient, rotary encoder counting and press detection, button detection (with debouncing), and serial port data transmission. J-Link was used for downloading and debugging. The rainbow gradient effect is shown in the attached video. The "MSPM0G3507_DevBoard_Test.rar" file in the attachment is the CCS project file for the test routines.
Interestingly
  , the MSPM0G3507 chip on LCSC's online store is now significantly cheaper than when it was first manufactured, and there's also a much larger inventory. Perhaps I've contributed a little to the price reduction of M0 microcontrollers? Also, I've recently decided to write some MSPM0 learning notes, which I'll update sporadically on CSDN. Feel free to check them out if you're interested: MSPM0 Learning Notes