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Procedure of Power On

Other Parts Discussed in Thread: MSP-TS430PZ100A

I have question on the procedure of power on when I use JTAG debugger.

I have

I1. Target Board (e.g. MSP-TS430PZ100A)

I2. JTAG Debugger (e.g. MSP-FETU430IF)


The procedure to start JTAG debugging includes (the order is arbitrary in the following):

A1. connection of cable between MSP-FETU430IF and PC (Then JTAG debugger is powered on)

A2. connection of cable between MSP-FETU430IF and MSP-TS430PZ100A

A3. Power on MSP-TS430PZ100A


Is the procedure A3 should be after A2 always? If I do A3 before A1 and A2, does this cause

breakdown of hardware (JTAG Debugger or Target Board)?


I did not take care of this kind of procedure using MSP-TS430PZ100A for a long time, but my colleage

advised me to check the procedure so that breakdown of hardware does not occur (especially

when in the case of a target board without some protection circuit).


  • The MSP430 is a very robust thing. It can stand a lot of stress.

    Normally, it shouldn't make any difference if you first power the board, then connect the debugger and then power the debugger. The problematic overvoltages on the data lines should be kept under control by serial resistors in the programmer, so the current is below the clamp current of 2mA per pin (which will flow to the programmers VCC and power it up indirectly).

    Since USB has a common ground with the PC, there could be ground loops between the PC and the boards othe rpower source. But these will happen independently of the connection order. If you have a ground level problem, it will probably destroy your MSP or the programmer, no matter in which order you connect them. If not, the order shouldn't matter.

    I never cared for the connection order for years (with serial FET and now the USB FET) and never burned any MSP (and there were _many_ devices I programmed)

  • Thank you very much for your reply, Jens-Michael.


    So, in the case of MSP430, we do not need to care the order of power on.


    It is good to hear that you did not have the problem for years without taking care of the order.


    Thank you very much.


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