Re: msp430-gdbproxy loses connection with target

MSP430FG4618 erratum TB18: MOV to TBCTL may clear TBR.

http://www.ti.com/lit/er/slaz368c/slaz368c.pdf page 9.

Peter


On Tue, Sep 17, 2013 at 11:09 PM, Andrew McLaren <[email protected]>wrote:

> Just to close the loop on this, I think I have found the problem (or at
> least what the 439 MSP doesn't like).
>
> The logic maintains a reference timebase using the timer B module (this
> simply ticks away in the background and maintains a reference counter). To
> obtain a time reference at any time, the logic stops the timer block, reads
> the TBR, and restarts the timer block. Nothing really fancy there.
>
> It was a bit of luck, but the only other relatively large MSP I had
> available was the 4618 on an experimenters board. This also has a USART, so
> there were only minimal code changes needed between the 439 and the 4618
> (the 4618 is a USART1 rather than a USART0, and that was pretty much it).
> However, the 4618 timer logic failed - when the timer was restarted, the
> TBR
> was cleared, whereas the 439 restarted (as expected) from where the TBR was
> stopped. This lead me to have a good look at how the timer block was
> stopped
> and restarted.
>
> To stop and restart the timer, the whole TBCTL was being rewritten, along
> the lines of;
> TBCTL = TBSSEL_1 | ID_3 | MC_0, and
> TBCTL = TBSSEL_1 | ID_3 | MC_2
>
> This worked fine on the 439 (or at least appeared to work fine!). However
> stopping the timer block this way appeared to clear the TBR on the 4618,
> even though the TBCLR bit wasn't being set. To get this to work correctly
> on
> the 4618, I modified this to just touch the mode control bits, along the
> lines of;
> TBCTL = TBCTL & ~MC0 & ~MC1
> TBCTL = (TBCTL & ~MC0) | MC1
>
> This resolved the timer issues with the 4618, which now ran the logic with
> no problems. Moreover, the logic functioned without any of the loss of
> connectivity with the JTAG seen with the 439. Just out of curiousity, I
> rebuilt the logic for the 439 and ran that again, and it also worked 100%.
> I
> could turn the JTAG connectivity issues on and off simply by how I was
> touching the TBCTL register.
>
> A bit more playing and looking at the full TBCTL before I modify it, the
> only difference between two two is that in the first case TBIFG is being
> cleared, whereas in the modified case this is being left at its set state.
> As I'm not using TBIE or TBIFG, this doesn't affect me at all. While the
> second TBCTL strategy is explicitly only touching what is required, so is
> probably better, I can't see why the initial strategy should have caused
> any
> issues (and also why it should have cleared the TBR on 4618, but luckily it
> did!).
>
> Its curiousity value now, but if anyone can give me any insights into why
> this has happened, I'd like to know! Thanks for the help and pointers in
> resolving this.
>
> Andrew
>
> -----Original Message-----
> From: Eric Decker [mailto:[email protected]]
> Sent: Tuesday, 3 September 2013 10:57 a.m.
> To: [email protected]
> Cc: Daniel Beer; GCC for MSP430 - http://mspgcc.sf.net
> Subject: Re: [Mspgcc-users] msp430-gdbproxy loses connection with target
>
>
> have you verified that the board is getting the voltage that you think it
> should be?
>
>
> On Mon, Sep 2, 2013 at 3:38 PM, Andrew McLaren <[email protected]>
> wrote:
>
>
> >
> > On Tue, Aug 27, 2013 at 10:40:45AM +1200, Andrew McLaren wrote:
> > > It would have been easy if the problem had been gdbproxy,
> > but no such
> > > luck. Now that mspdebug is running, I'm seeing exactly the same
> > > scenario here. The messages are a tad different, but I
> > think they are
> > > saying the same thing. Everything works fine until mspdebug
> > reports...
> > >
> > > fet: FET returned error code 18 (Could not determine device state)
> > > fet: polling failed
> > >
> > > Once again, eveything appears hung outboard of mspdebug until the
> > > target msp is repowered. If I simply try and restart
> > mspdebug without
> > > doing this, it will report;
> > >
> > > TI3410 device is in boot config, setting active
> > > ti3410: TI_OPEN_PORT failed: A device attached to the system is not
> > > functioning
> > > ti3410: failed to set up port
> >
> > This looks like some kind of hardware problem. Have you tried
> > different USB ports?
> >
> > Is the board powered externally, or does it draw power from the FET?
> >
> > Cheers,
> > Daniel
> >
>
> I've been having a bit of a play to try and isolate it, but haven't come up
> with anything conclusive (or really anthing at all).
>
> To answer your questions
> - the target board is powered by the FET
> - I've tried switching USB ports, but no change.
>
> I've also tried switching the target processor (another 439), but also no
> change. The only harware I haven't yet swapped out is the FET itself, but
> only have the single TI FET running. I do have an Olimex FET here, but
> having a few issues at present installing the drivers for that, so that is
> the next step.
>
> The ONLY thing I have found so far that resets the problem is repowering
> the
> target MSP, which leads me to think that is must be some context in that
> that is somehow being corrupted. I'd also like to try a different MSP
> variant, but none of the others I have here have the ROM space this needs
> (just thinking, I do have one of the TI experimeter boards around, and that
> has a fairly hefty MSP on it, so that could be worth a go).
>
> So I have a couple of things to try. I'll keep you posted.
>
> Andrew
>
>
>
>
>
>
> --
> Eric B. Decker
> Senior (over 50 :-) Researcher
>
>
>
>
>
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