Thursday, December 15, 2011

Am I the only person in the world having problems with Launchpad?

The TI MSP430 Launchpad is absolutely great.  For a great take on the thing, watch EEVBlog #92.  [Dave, you are great.  Sometime I hope I can do similar stuff, even if I can't be as good as you are.]

I like the Launchpad too, but it has been a bit of a love-hate relationship so far.

Every emulation tool has quirks.  However, I must be the only one having problems with the Launchpad, as nobody else seems to be mentioning it.  That makes me very unlucky, very inventive, or very dumb (or all three).

Here's what I've found so far:

"Failed to initialize" error:  can be caused by several things.  I've had a terrible time figuring this one out.

Fixes so far:

-  If you unplug the Launchpad while IAR EW is running, IAR may fail to reconnect.  Restart IAR.

-  Oddly enough, rebooting the machine does actually help sometimes.

-  In one case, the mini-USB connector was plugged in far enough to give power, but not fully engaged, leaving the serial comm lines unconnected.  (That was a fun one.)

-  Unplug the USB cable and check the power LED of the Launchpad.  Is it still on?  If so, you are getting parasitic power from an I/O line or other connection, which appears to royally screw up the emulator code loading process.  Check all your I/O to see where the offending line is, and fix it.

-  Disconnect everything.  (This is where the header/socket system provided with the Launchpad is handy.)  Unplug/replug, restart IAR, try again.

-  Go back to the 'flash the LED' program.  Sometimes, it seems that code will download when others will not, after which your code will again download.

-  Go back to one of the two stock chips provided with the Launchpad.  I have not been able to get a 'G2152 to load, no matter what I try, but the '2231 loads the same code just fine.

Timer A not running from ACLK / ACLK not running from 32.768 kHz crystal:  mine did not oscillate reliably until I unsoldered the crystal from the ground pad.  (Why TI would thoughtfully provide a mounting pad on the PCB that you're not supposed to use with the supplied crystal is beyond me.)  The crystal would oscillate, but only in short bursts, and with terrible accuracy.

I didn't figure this one out until I grabbed the crystal lines on the pin header and it suddenly started to work (albeit crappily).  It was obvious then there was some kind of issue with the load capacitance.

You can look at ACLK (and SMCLK) by setting the right bits and scoping P1.0 (ACLK) or P1.4 (SMCLK).  This drives the clock output to the I/O so you can observe it without unduly loading the crystal itself down with the scope probe.

If I can just get past the "failed to initialize" problem, I'd be a lot happier.  So far, it's been pretty random, pretty intermittent, and pretty irritating.

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