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MSPM0L1105: External circuitry for smallest size

franziskus
Expert 8319 points
Part Number: MSPM0L1105

Team,

my customer needs a very small solution size. They have some questions regarding the circuitry shown in Application Note „MSPM0 L-Series MCUs Hardware Development Guide“ (SLAAE75A) and potential to reduce size:

  1. To what value can the 10uF capacitor at VDD be reduced to a minimum?
  2. Can only one capacitor be used instead of the two capacitors on VDD?
  3. With STM controllers, it is possible to configure the NRST pin as GPIO. Thus, the resistor and the capacitor at NRST are eliminated.
    Is this also possible with TI's µCs?
  4. The 100kOhm is optional to improve the accuracy of the internal resonator, right?
  5. Can you buy TI programmed µCs? We set the program and TI programs and ship to the EMS.
    What would this cost per µC?

Best regards 

  • +1
    TI__Guru 70996 points

    Hi Franziskus,

    1. Absolute minimum is 4.7uF with the caveat the customer should validate the performance across all expected conditions for their application.

    2. The larger cap (10uF) is a "tank capacitor", which provides large currents to the MCU during peak current operations and is considered a required component.  The smaller 0.1uF is for filtering potential high frequency noise.  This could be considered 'optional', but again, without this 0.1uF the customer should validate the performance across all expected conditions for their application.

    3. Yes, partially.  The NRST pin can be reconfigured to GPIO by the application, but, prior to the application code performing the change over from NRST to GPIO, at POR the MCU needs to be brought out of RESET state by pulling the NRST pin high, such as with a pull up resistor.  So in summary, if the NRST is changed to GPIO input or output, a pull up resistor is still mandatory.

    4. Yes. Depending on your required system accuracy you may not need it.  Check section 7.9.1 in the datasheet for different specifications.

    5. Regarding pre-programming, I'll need to check on this.  My understanding is if purchased directly from TI, I don't believe so, but if purchased through a distributor I believe so.  Again let me confirm this.

  • 0 in reply to Dennis Lehman
    TI__Expert 8319 points

    Thanks for your quick reply Dennis!