gumstix

Hi Dan,

> The problem I have right now though, is that somewhere along the line,
> everything stopped working properly.  Now, even when I load the
> Flash-LED.hex file, it isn't flashing the LEDs correctly.  I have no idea
> what went wrong.  I went back to hooking it up to the gumstix, and tried
> resetting the fuses again and reloading the .hex file, and the LEDs still
> aren't lighting up the way they are supposed (if they even light up at all,
> it seems rather sporadic).  If this is happening now, do you think I fried
> the atmega128 somewhere along the line?  I'm new to developing with the
> atmega128, but I do have experience with other micro controllers.  I can't
> figure out what I possibly could have done to get the robostix to not
> function correctly.  Also, I never had the ISP hooked up to the robostix at
> the same time the gumstix was plugged intot he robostix.
>
> If you have any advice you can give me as far as trouble shooting this
> problem I would much appreciate it.

So, if its the case that the LEDs are light but just too slow
(sometimes way too slow) then it may just be incorrect fuse settings.

Also, two of the LEDs are on PortG which doesn't exist if you're in
ATMega103 compatability mode.

If you're using the STK500, then make sure you set the processor to
ATMega128 in the first tab, and then goto the fuses tab. If should
print out the fuse settings in hex down in the bottom of the window.

0xFF, 0xC9, 0xBF (it might also show as 0xFF, 0xCFBF)

See this page:
<http://docswiki.gumstix.com/Robostix_fuses>
for the step-by-step process.

If things are still not behaving properly, then try changing the fuses
to use the internal oscillator at 8 MHz.

The LEDs should flash at half their rate (since Flash-LED.hex as
designed for 16 MHz).

If it works on the internal oscillator and give erratic behaviour on
the external oscillator, then there is most likely a cold solder joint
around the oscillator. I've had this happen to me in the past, and
resoldering the oscillator fixed it for me.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

Dave,

Thanks for your quick reply.  The fuse settings were set to the correct
values.  Also, as soon as I switched to the internal 8 Mhz crystal,
everything ran fine.  So the external 16 MHz is acting flaky, but the
solder joints look okay, so I'm guess maybe somehow the crystal went
bad?  I have no idea because it (the external crystal) was working fine
yesterday...  If you have anymore suggestions please let me know.

Thank you,
Dan

-----Original Message-----
From: gumstix-users-bounces@...
[mailto:gumstix-users-bounces@...] On Behalf Of Dave
Hylands
Sent: Wednesday, June 27, 2007 3:13 PM
To: General mailing list for gumstix users.
Subject: Re: [Gumstix-users] Is my robostix fried?

Hi Dan,

> The problem I have right now though, is that somewhere along the line,

> everything stopped working properly.  Now, even when I load the=20
> Flash-LED.hex file, it isn't flashing the LEDs correctly.  I have no=20
> idea what went wrong.  I went back to hooking it up to the gumstix,=20
> and tried resetting the fuses again and reloading the .hex file, and=20
> the LEDs still aren't lighting up the way they are supposed (if they=20
> even light up at all, it seems rather sporadic).  If this is happening

> now, do you think I fried the atmega128 somewhere along the line?  I'm

> new to developing with the atmega128, but I do have experience with=20
> other micro controllers.  I can't figure out what I possibly could=20
> have done to get the robostix to not function correctly.  Also, I=20
> never had the ISP hooked up to the robostix at the same time the
gumstix was plugged intot he robostix.
>
> If you have any advice you can give me as far as trouble shooting this

> problem I would much appreciate it.

So, if its the case that the LEDs are light but just too slow (sometimes
way too slow) then it may just be incorrect fuse settings.

Also, two of the LEDs are on PortG which doesn't exist if you're in
ATMega103 compatability mode.

If you're using the STK500, then make sure you set the processor to
ATMega128 in the first tab, and then goto the fuses tab. If should print
out the fuse settings in hex down in the bottom of the window.

0xFF, 0xC9, 0xBF (it might also show as 0xFF, 0xCFBF)

See this page:
<http://docswiki.gumstix.com/Robostix_fuses>
for the step-by-step process.

If things are still not behaving properly, then try changing the fuses
to use the internal oscillator at 8 MHz.

The LEDs should flash at half their rate (since Flash-LED.hex as
designed for 16 MHz).

If it works on the internal oscillator and give erratic behaviour on the
external oscillator, then there is most likely a cold solder joint
around the oscillator. I've had this happen to me in the past, and
resoldering the oscillator fixed it for me.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

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Hi Dan,

> Thanks for your quick reply.  The fuse settings were set to the correct
> values.  Also, as soon as I switched to the internal 8 Mhz crystal,
> everything ran fine.  So the external 16 MHz is acting flaky, but the
> solder joints look okay, so I'm guess maybe somehow the crystal went
> bad?  I have no idea because it (the external crystal) was working fine
> yesterday...  If you have anymore suggestions please let me know.

Solder joints can be deceiving.

You have (at least) the following options:

1 - If you purchased it recently (i.e. it's still within the RMA
period), you should be able to return it.

2 - You could just use the internal oscillator (not appropriate for
all situations).

3 - You could try touching up the solder (cold solder joints often
look good but aren't)

4 - You could try replacing the crystal.

Note for options 3 & 4, if the crystal becomes disconnected (and the
fuses are set to use it), then the robostix will no longer respond to
programming, nor will it function properly. Obviously, soldering on a
good crystal will make it work. You can also recover by using
something else to generate a clock (pretty much anything will do) and
touching it to pin 24 long enough to allow you to change over to the
internal RC clock.

The STK500 has a clock source on it that I've used in this manner.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/