Sort of off topic discussion,
You don't have the corresponding IE set in the ADC12IE control register. You
need:
ADC12IE = 0x1; // Select IRQ for ADCMEM0
ADC12MCTL0 = INCH_0 + SREF_0; // Select channel A0, AVcc
As for ADC12MCTL0, I never like trusting that these variables will be set to
all zero's,
so I make sure to initiate to whatever I want, even set it to zero if that's
what I
want.
Make sure to capture the data from the ADC like this:
interrupt (ADC_VECTOR) ADCIRQ(void)
{
adcraw = ADC12MEM0; // Move results, IFG is auto-cleared
}
Also, probably want to declare adcraw as volatile. Remember, if you access it
twice in
the same main loop, you might get different results. So, only access it once
(per
loop).
In fact, the method I described has a few other differences. I suggested
having the
TimerA IRQ trigger the Start conversion. In order to do that, set:
ADC12CTL1 = SHP; // ADC12SC starts conversion
TACTL = TASSEL_2+MC_2+TAIE; // Timer_A setup
And add this line to the TimerA IRQ routine:
interrupt (TIMERA1_VECTOR) TimerA1( void )
{
ADC12CTL0 |= ADC12SC; // Perform one conversion
}
Hope this doesn't make things more confusing. The ADC is definitely confusing.
Also,
I'm not an expert at using TimerA in this regards. I am using TimerB similar
to this (I
know, they are similar, etc). One more thing. Make sure SMCLK is running.
Might be
better to recalculate the TimerA frequency based on ACLK, that way all of this
can
happen in LPM3. To test SMCLK, just set it to be output on the SMCLK output
(temporarily). Also, a quick LED and a simple code toggle on the TimerA IRQ
would let
you know the ADC is being told to start.
Enjoy and good luck!
-Mark
-----Original Message-----
From: Gao Zhengsu [mailto:g...@clarkson.edu]
Sent: Wednesday, April 14, 2004 1:44 PM
To: mspgcc-users@lists.sourceforge.net
Subject: Re: [Mspgcc-users] About msp430x149
Hi,Mark
Thank you for your good way!!
I read manual said that we can use TamerA OUTPUT UNIT1 to trigger ADC12
conversion like this
TACTL = TASSEL_2+MC_2; // Timer_A setup
TACCTL1 = OUTMOD_3; // CCR1 setup
TACCR1 = 0x0fff; // Compare value
ADC12CTL0 = ADC12ON+SHT0_2; // Turn on ADC12, set sampling time
ADC12CTL1 = SHS_1+SHP; // TAOUT.1 triggers sampling timer
ADC12CTL0 |= ENC; // Enable conversions
ADC12CTL0 |= ADC12SC; // Start conversion
but this doen's work to my code , it never stop by ADC interrupt routine.
What's the reason?
Thank you!
Regards
Zhengsu
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