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MSP430 with FET430UIF programmer issue

Alan Williams
Prodigy 40 points
Other Parts Discussed in Thread: MSP430F5529

Hi,

I have an issue with the MSP430 that is puzzling me. I have been through the guides and forums but I’m not finding anything on it. 

The issue is around the FET430 programmer. If am using the MSP-FET430UIF programmer to program the MSP430F5529 device in Spy by wire mode (2 wire.) 

The configuration is that the PCBA provides the VCC to the programmer.

 When I power the board without the programmer fitted, I see the following:

The purple line is the RSTN/NMI/SBWTDIO, the Blue line is Vcore.

 The MSP430 powers up and begins running it’s code, I am able to connect the programmer and program the device without issue.

 However, if I power the board with the programmer fitted, I see the following:

I have the following observations:

  1. RSTN/NMI/SBWTDIO sits at ~ 0.5V as soon as the programming cable is connected (i.e. before power on.)
  2. When it (and DVCC) reaches ~1.1V there is a reset pulse initiated by, I assume, the programmer (or the MSP430?)
  3. The VCORE comes up but then collapses.

 I have powered the board up like this and then manually cycled the reset but it does not recover, i.e. VCORE remains at 0V.

 The only way I can recover is to remove the programmer and power cycle the unit.

Below is a snapshot of the programmer cable area of the schematic, I have checked it against the TI recommendations and I don’t see any obvious differences.

 Note I removed C895 (2.2nF)  in case this was causing issues but this has made no difference, however the ramp rate of the supply (~0.5V/ms) means that the RST input follows the 3V3 quite closely during ramp up, with or without the 2.2nF/47KR arrangement on RST.. maybe that’s the issue?

Thanks in advance for any help.

  • 0
    Intellectual 310 points

    Hi Alan,

    I used spy-by-wire to program MSP430F201x controllers, had no problem, but used programmer for powering, no external power source connected to device. Maybe you could try the same (R415 - dnp, R416 - 0, and no external power source), that is, off course, if your USB hub power strength is high enough for the application. I would try removing both resistors for external powering. When it comes to capacitor - do not place it while programming, but place for standalone operation.

    For MSP430F5529 programming I used JTAG programmer, not spy-by-wire. It worked fine with JTAG, so if you don't find a solution for your problem you may switch to it.

  • 0
    Guru 46710 points

    Check your application against any FET-related pin usage. Perhaps app is setting some pin high while FET (still) pulling it down, supply does not sustain such a "short".

  • 0
    Genius 3155 points

    That ~500us pulse makes me think you could be affected by errata PORT16 (slaz314, page 22). Do you have any pin that is not present on 64 pins variants of same family and could draw an "high" current if driven low by the MCU?

  • 0 in reply to Piergiuseppe Tundo
    Prodigy 40 points

    Hi all,

    Thanks for your suggestions. Just to update you, I managed to look at this again yesterday, and think I may have found what was wrong.. I've only tested it with one board however so I'd be reluctant to claim a fix yet.

    I followed a suggestion from TI and checked the board against the MSP-TS430NP80USB evaluation module. Firstly I found that SBW worked reliably on that board when i configured it to power the same way as mine. Secondly I found that of our three debugger/programmer cables, 1 worked on my design, and two didn't.

    I compared the schematics and found two differences between my board and the evaluation module from a programmer perspective.

    1. 330R between TEST net of MSP430 and pin 7 of the JTAG header on the evaluation module.

    2. TEST net of MSP430 is tied to pin 8 on the evaluation module JTAG header.

    Essentially, the evaluation module was wired as per figure 2-2 of SLAU278M:

    My board was wired as per Fig 2-3 of the same document:

    I changed my board to reflect Fig 2-2 and it all works. It now boots when the debugger is connected and power is applied, there is no longer a reset pulse applied by the debugger during power up.

    Note my device is an MSP430F5529, so according to that document it should be wired up as Figure 2-3, not 2-2. I am not sure why I had to do this. Those changes I had to put in are referenced in Note C of the diagram as being required to allow a security fuse to be blown. I have a question with TI to hopefully shed some light on why this is needing done.

    Cheers,

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