Thank you, Wayne!
After reading your response I understood I've been reading incorrect
registers to check for Interrupt flag. Here is a snippet of the code
that worked for me:
============ code ==================
// Timer A0 interrupt service routine (at top value)
#pragma vector=TIMER0_A0_VECTOR
__interrupt void Timer_A0 (void) {
_NOP();
}
// Timer A1 interrupt service routine (in the middle)
#pragma vector=TIMER0_A1_VECTOR
__interrupt void Timer_A1 (void) {
if (TAIV == TA0IV_TACCR1) {
TACCTL1 &= ~(TAIFG); // clear interrupt flag
}
}
============ end of code ============
After reading some example I also realized that it's better to use
switch() during TIMER0_A1_VECTOR interrupt "routing" - this allows to
read TAIV only once and select the appropriate interrupt.
--
Best regards,
Kirill Popov.
----
Other ways to contact me:
Gtalk: kirill.s.po...@gmail.com
Cell phone: +79052062619
LinkedIn: http://ru.linkedin.com/in/kspopov
On Fri, Jul 4, 2014 at 10:57 AM, Wayne Uroda <w.ur...@gmail.com> wrote:
> I believe your problem is that in the timer A1 ISR, you need to read from
> TA0IV in order to clear the interrupt (timer A1 isn't fired from an
> interrupt flag but rather from the grouping of events which are then routed
> through TA0IV, unless I am mistaken)
>
> 17.2.6 Timer_A Interrupts
> Two interrupt vectors are associated with the 16-bit Timer_A module:
> • TAxCCR0 interrupt vector for TAxCCR0 CCIFG
> • TAxIV interrupt vector for all other CCIFG flags and TAIFG
>
> 17.2.6.1 TAxCCR0 Interrupt
> ... The TAxCCR0 CCIFG flag is automatically reset when the TAxCCR0 interrupt
> request is serviced.
>
> 17.2.6.2 TAxIV, Interrupt Vector Generator
> ...
> Any access, read or write, of the TAxIV register automatically resets the
> highest-pending interrupt flag. If
> another interrupt flag is set, another interrupt is immediately generated
> after servicing the initial interrupt.
> ...
>
> - Wayne
>
>
> On Fri, Jul 4, 2014 at 4:22 PM, Kirill Popov <kirill.s.po...@gmail.com>
> wrote:
>>
>> Hello!
>> I've got an issue with using __delay_cycles() while also utilizing
>> TimerA interrupts.
>> It seems that __delay_cycles(); is not working if TimerA interrupts
>> are enabled. Even if nothing is done in interrupt routine.
>> Here is a sample code:
>> ========== main.c ============
>> #include <msp430g2553.h>
>>
>> // Timer A0 interrupt service routine (at top value)
>> #pragma vector=TIMER0_A0_VECTOR
>> __interrupt void Timer_A0 (void) {
>> TACCTL0 &= ~(TAIFG); // clear interrupt flag
>> }
>>
>> // Timer A1 interrupt service routine (in the middle)
>> #pragma vector=TIMER0_A1_VECTOR
>> __interrupt void Timer_A1 (void) {
>> if (TACCTL1 & TAIFG) {
>> TACCTL1 &= ~(TAIFG); // clear interrupt flag
>> }
>> }
>>
>> int main(void) {
>> WDTCTL = WDTHOLD | WDTPW; //halt watchdog
>> P1REN = ~(BIT6); // pull-ups are disabled on pins 0 and 6
>> P1DIR |= BIT6; // pins 0 and 6 are outputs
>> P1OUT &= ~(BIT6); // pin 6 and pin 0 are LOW
>>
>> TACCR0 = 0x0fff; // set top value for timerA
>> TACCR1 = 0x00ff; //set LED glow power
>> TACCTL0 = (CCIE); // enable compare interrupt for TACCR0
>> TACCTL1 = (CCIE); // enable compare interrupt for TACCR1
>> TACTL = (TASSEL1 | MC0 | TACLR | TAIE); // SMCLK, cnt UP, clear,
>> interrupt
>> _BIS_SR(GIE); // enable blobal interrupts
>> for (;;) {
>> P1OUT ^= BIT6;
>> __delay_cycles(1000000);
>> }
>> return 0;
>> }
>> ======== end of main.c =============
>>
>> I expect this code to blink with a LED on P1.6 with approximately 1
>> second interval (no precise timing required). But all I see is the LED
>> just lit all the time.
>> If I comment out the line with _BIS_SR(GIE); the LED is blinking as
>> expected.
>>
>> What could be the reason? My guess is interrupt routine is somehow
>> spoiling registers used by __delay_cycles(). Is that true?
>> Would be thankful for a workaround if there is such.
>>
>> I'm using msp430-gcc (GCC) 4.6.3 20120301 (mspgcc LTS 20120406
>> unpatched) from Debian repository to build code for TI Launchpad
>> MSP-EXP430G2 (M430G2553 chip).
>>
>> Thank you!
>> --
>> Best regards,
>> Kirill Popov.
>>
>> ----
>> Other ways to contact me:
>> Gtalk: kirill.s.po...@gmail.com
>> Cell phone: +79052062619
>> LinkedIn: http://ru.linkedin.com/in/kspopov
>>
>>
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>
>
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http://p.sf.net/sfu/Bonitasoft
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