RE: Problems with IAR and programming

Hi Emmett

I do need the 12V input to my target board as it is used to supply a
switching regulator which supplies 11.3V. This in turn goes to another board
to be used to supply a 3G modem. This board is not connected. The 11.3 volts
is also used to supply a Lipo battery charger. It is on the same board but
no battery connected. At present my PW28 board is supplied by a
plugpack(wall wart) which delivers 3.3V to the PW28 board. The settings on
this are for ext power.

I am sure you are correct with the power supplies conflicting or some noise
interference. I have just noticed that the plugpack to supply the 12V is an
older unregulated one. On no load the voltage is on about 18V. I will swap
this for a regulated one. However, my regulator is capable of handling up to
35V. I have used this same circuit many times before without any problems so
it is probably not noise.
In answer to your questions 
1. No I do not have to have both on. I will continue to have my regulated
12V in to my target board and remove the 3.3V plugpack and change the
setting on PW28 to INT. 
2. I can disconnect this wire and see what happens.
3. These boards are not in a case yet, just sitting on the bench while I am
starting the debugging.

This does help me as I was starting to stall. I will advise the outcome. 

Thanks for the assistance.


Peter

-----Original Message-----
From: [email protected] [mailto:[email protected]] 
Sent: Saturday, 21 February 2015 8:33 PM
To: [email protected]
Subject: RE: [msp430] 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 and 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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Posted by: "Peter Grey" <[email protected]>
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