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CCS/MSP430I2020: osc

Part Number: MSP430I2020

Tool/software: Code Composer Studio

Dear Sir,

I want use external crystal for the main clock in order to get the low frequency temperature drift. What is the value of load capacitance, equivalent Series resistance of crystal or external capacitor is suggested?

Best regards,

Theo

  • Hi Hung,

    The DCO Bypass Mode and DCO Operation in External Resistor Mode could be your reference in the device User's Guide.
  • Hi Wei,

    From the spec. of DCO in External Resistor Mode, (recommended resistor at ROSC pin: 20 kΩ, 0.1%, ±50 ppm/°C), it mentioned that frequency temperature drift has ±20 ppm/°C. When we operate the device from -20 to 65 deg C, there are (65-(-20)) temperature difference. Therefore, tolerance will be 85 x20 ppm
    However, some crystal mention that it can get +/-80 ppm or lower. Is it possible to use the crystal for our main clock?
    My operate freq. use is 8M or 4MHz
  • Hi Wei,

    From the spec. of DCO in External Resistor Mode, (recommended resistor at ROSC pin: 20 kΩ, 0.1%, ±50 ppm/°C), it mentioned that frequency temperature drift has ±20 ppm/°C. When we operate the device from -20 to 65 deg C, there are (65-(-20)) temperature difference. Therefore, tolerance will be 85 x20 ppm
    However, some crystal mention that it can get +/-80 ppm or lower. Is it possible to use the crystal for our main clock?
    My operate freq. use is 8M or 4MHz

    Best regards,

    Theo

  • Hi Hung,

    Then you could use the DCO Bypass Mode for an external digital clock source.
  • Hi Wei,

    As my last reply email, my question is that MSP430I2020 can be use together with external crystal?

    External crystal can get better performance?

    Best regards,

    Theo

  • Hi Hung,

    Sure, you could use the external crystal for main clock by DCO Bypass Mode.

    The performance should depends on the external crystal itself. By the DCO Bypass Mode, you just have another choice for your main clock source.

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