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OSC of MSP430f6438 and JTAG interface

dison wang
Expert 1620 points
Other Parts Discussed in Thread: MSP430F6438

Hi Dear,

I have few questions about MSP430F6438 MCU. Is there some one know answer.

Q1.  If  the extra OSC (32khz to XT1)  must works, before I program the MCU by JTAG interface. Which one is a define clock source in MSP430F6438?

Q2, Do it need  external capacitors, if  I use a 32khz crystal on XT1 for MSP430F6438.

Q3, If the external capacitors is necessary, would you know how much pf  it is. 

I read the datasheet of MSP430F6438, it said put a 32khz crystal on XT1 without any extra parts. I did like that, but it did not works. I read the Application Report-SLAA322B-MSP430 32-kHz Crystal Oscillators, it said MSP430 family need extra capacitors difference capacitors depend on  MSP430Fx. I try it too, but it is still did not work. So I have Q2 and Q3.

I note some discussion online which are about how to setup the OSC of MSP430 MCU. So I have the Q1.

Is there some one can give me answer.

Thanks,

Dison

  • 0
    TI__Prodigy 735 points
    Hi Dison,

    Q1:
    You do not need a working/running 32kHz crystal to program the DUT by JTAG. By default MCLK will be sourced by the internal DCO, the ACLK expects a 32kHz crystal at XT1. If no crystal is present the fault logic of the CS-Module will source the ACLK by the internal REFO.

    Q2:
    The MSPF6438 has internal caps for the XT1. You can select four different effective loads. You need to match this setting to the needs of your crystal. The setting can be found in register UCSCTL6. If you did not change this setting it defaults to 12pF which might be to high for your crystal.

    Q3:
    That depends on the crystal you use. You will find this information in the datasheet of the crystal.

    Thanks and best regards,
    Christoph
  • 0 in reply to Christoph Dohrn
    Expert 1620 points

    Hi Christoph,

    OK, I got it.

    Thanks,

    Dison

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