RE: Problems with IAR and programming

I have many times used the SoftBaugh board with the MSP430F2274 that goes with their MSP430 State Machine book with my students.  Not always, but often enough, similar non-operation happens when it is being supplied by its wall-wart supply and the SoftBaugh USBP programmer.  Occasionally, the PC locked up and had to be rebooted.  Since it was easy enough to remind students to have only one or the other but not both sources of power connected, they could proceed with the programming and then separately test operation and measure currents etc. 

I never investigated further.

My suspicions are that the two power supplies conflict, cause large currents to flow, and generate noise that interferes with the digital signals.  Ground loops may also be involved and can cause similar noise issues.

Some (rhetorical) questions for you:

1. Do you ABSOLUTELY have to have both power-supplying devices connected at the same time to accomplish your desired task?

2. Can you disconnect just the Vcc wire going from your FET to your target board?

3. Consider ALL possible ground loops and breaking them. (Techniques may vary and even include 2-to-3 prong adapters on the power cords since the Safety Ground wire and the Grounded Neutral wire are sometimes both connected to equipment cases either by design or accident or the case ground is also the circuit ground, again, either by design or accident.)  Ground loops are subtle and, sometimes, are cleared without knowing what action actually cleared them.

HTH

Emmett Redd Ph.D.   mailto:[email protected]
Professor                                 (417)836-5221
Department of Physics, Astronomy, and Materials Science
Missouri State University             Fax (417)836-6226
901 SOUTH NATIONAL                   Lab (417)836-3770
SPRINGFIELD, MO  65897   USA    Dept (417)836-5131

In statesmanship get the formalities right, never mind about the moralities. -- Mark Twain.
________________________________________
From: [email protected] [[email protected]]
Sent: Friday, February 20, 2015 11:12 PM
To: [email protected]
Subject: [msp430] Problems with IAR and programming

I have a target board with a MSP430FR5729. I am using IAR EW6.5 and a MSP430-FETUIF. I have a MSP-TS430PW28 connected to the FET module and 4 wires going to my target board (Vcc, ground, Test, RST). I have used this sort of setup many times. My target board has a 12V input and it generates 11volts to be used on board to generate 3.3V and a few other DC voltages. When I connect the cable from the PW28 board I can program the board and run it. If I connect the 12 volts to my target board the IAR crashes and I have to turn my PC off and on. When the 12V is not on the Vcc is 3.32V and if I have the 12V connected and no FET the Vcc is 3.29V. I cannot see any shorts to ground and the whole target board draws 17mA when no high power devices are connected (3G modem). I can program in a led flash a
 nd this will work with no 12V connected. If I remove the FET and apply power the fled will flash. It seems the program runs but it will not download the program when I have the 12V connected. I checked the notes from TI and can see no hints as to what is happening.


Any suggestions?

TIA

Peter





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