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JTAG Connection to MSP430

Tom Kealy
Prodigy 10 points

Hi I am currently working on a college project using the MSP430 chip to implement an electricity meter.

I have shown how I am powering the device and using a JTAG connection to programme the device.

JTAG is set up as it should be, but alas when I connected to code composer it says unknown device.

I am reading 3.03 v on the AVcc and 2.96 v on the DVcc.

Any suggestions as to why the device is not being recognized in code composer would be greatly appreciated.

Regards,

Tom K

  • 0
    Guru 227245 points

    You don't need R32 and I guess, C30 is a bit oversized (10F, you probably meant 10µF - I'd put 100µf or more here, but from 10F you could drive the MSP for months)

    I don't think that 100nF between DVSS2 and VSS are a good idea. Best case, the capacitor is shorted, since DVSS1 and DVSS2 ar einternnally connected and DVSS1 is connected to VSS.

    10nF on DVCC2 are nice, but only if directly placed besides the pin. And then there should be 10nF on DVCC1 too. ASnd some more in maybe a greater distance.

    C29 should be a tantalum. It doesn't have to flatten much ripple current, but should be low noise and low-leakage. Tantalum excels here.

    You haven't connected AVSS1. The MSp won't stop working without, but to get a good analog response, you should route it separately from DVSS/VSS to the power supply. So you don't have any voltage drop on it due to the operating currents of the digital part.

    if you do not connect it at all, it will get connected to DVSS by the clamp diodes, but this means some voltage drop that appears as offset voltage on analog operations.

    However, all these shouldn't hinder the FET to access the MSP for programming/debugging.

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