SDAA132 December   2025 MSPM33C321A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 MSPM33C Hardware Design Check List
  5. 2 Power Supplies in MSPM33C Devices
    1. 2.1 Digital Power Supply
    2. 2.2 Analog Power Supply
    3. 2.3 Built-in Power Supply and Voltage Reference
    4. 2.4 Recommended Decoupling Circuit for Power Supply
    5. 2.5 Recommended Decoupling Circuit for VBAT
  6. 3 Reset and Power Supply Supervisor
    1. 3.1 Digital Power Supply
    2. 3.2 Power Supply Supervisor
  7. 4 Clock System
    1. 4.1 Internal Oscillators
    2. 4.2 External Oscillators
    3. 4.3 External Clock Output (CLK_OUT)
    4. 4.4 Frequency Clock Counter (FCC)
  8. 5 Debugger
    1. 5.1 Debug Port Pins and Pinout
    2. 5.2 Debug Port Connection With Standard JTAG Connector
  9. 6 Key Analog Peripherals
    1. 6.1 ADC Design Considerations
    2. 6.2 COMP Design Considerations
  10. 7 Key Digital Peripherals
    1. 7.1 Timer Resources and Design Considerations
    2. 7.2 UART and LIN Resources and Design Considerations
    3. 7.3 MCAN Design Considerations
    4. 7.4 I2C and SPI Design Considerations
    5. 7.5 I2S/TDM Design Considerations
    6. 7.6 QSPI Design Considerations
  11. 8 GPIOs
    1. 8.1 GPIO Output Switching Speed and Load Capacitance
    2. 8.2 GPIO Current Sink and Source
    3. 8.3 High-Speed GPIOs (HSIO)
    4. 8.4 High-Drive GPIOs (HDIO)
    5. 8.5 Communicate With a 1.8V Device Without a Level Shifter
    6. 8.6 Unused Pins Connection
  12. 9 Layout Guides
    1. 9.1 Power Supply Layout
    2. 9.2 Considerations for Ground Layout
    3. 9.3 Traces, Vias, and Other PCB Components
    4. 9.4 How to Select Board Layers and Recommended Stack-up
  13. 10Bootloader
    1. 10.1 Bootloader Introduction
    2. 10.2 Bootloader Hardware Design Considerations
      1. 10.2.1 Physical Communication interfaces
      2. 10.2.2 Hardware Invocation
  14. 11Summary
  15. 12References

8.6 Unused Pins Connection

All microcontrollers are designed for a variety of applications and often a particular application does not use 100% of the MCU resources. To increase EMC performance, unused clocks, counters or I/Os, must not be left free or floating. For example, set I/Os to 0 or 1 (pullup or pulldown enabled on the unused I/O pins) and disable unused features.

Table 8-3 Connection of Unused Pins
Pin Potential Comment
GPIO Open Set corresponding pin functions to GPIO (PINCMx.PF = 0x1) and configure unused pins to output low or input with internal pullup/pulldown resistor.
NRST VDD NRST is an active-low reset signal and must be pulled high to VDD or the device cannot start.
Note:
  • To reduce leakage, configure the I/O as an analog input or to push-pull and to set to 0.
  • BSL invoke pin must be pulled down to avoid entering BSL mode after reset.