MSP430FR2355 count frequency

Hi Elham,

The frequency of your sensor's signal is 5 - 6MHz? Right?

I think this is too high, and MSP430FR2355's max MCLK is 24MHz.

Thanks!

Best Regards

Johnson

Hi Johnson

Thank you for your reply.

My goals is to find in some different range for example (1 - 1.2 MHz, 2-2.4MHz, 3-3.5MHz and 5-6MHz).

Best Regards

Elham

Hi Elham,

Just a idea: maybe you can try use a COMP to trigger timer, then use the counter value to to distinguish different frequencies.

Thanks!

Best Regards

Johnson

This thread deals with a similar question. Maybe there's something useful there?

https://e2e.ti.com/support/microcontrollers/msp-low-power-microcontrollers-group/msp430/f/msp-low-power-microcontroller-forum/1067764/msp430fr2355-frequency-counter

Hi Johnson

Thank you for your reply.

I will test with your idea and get back to you as soon as possible.

Best Regards

Elham

Hi Bruce

Thank you for your answer,

As I understand from your link, this is like the my question.

I will take a look and come back to you soon.

Best Regards

Elham

Hi Elham,

Any update here, do you still need support?

Thanks!

Best Regards

Johnson

Hi Johnson

Thank you for your reply.

Not yet, I couldn't find correct example for it. 

I'm looking at some code for a frequency counter. I'm new in MSP and still learning but I think the code should be fairly straightforward.

Could you please help me to solving this problem??

Best Regards

Elham 

Hi Elham,

You can refer this example:

https://dev.ti.com/tirex/explore/node?node=ANcmdW6geYSVsxVVNMB9rA__IOGqZri__LATEST

Best Regards

Johnson

Dear Johnson

Thank you for your reply.

I am using MSP430FR2355 launchpad, and I don't have access to P2.7. 

Can I use another pin instance of P2.7?

Best Regards

Elham 

Hi Elham,

You have to use TBxCLK pin, like P5.2(TB2CLK):

Thanks!

Best Regards

Johnson

Dear Johnson

Thank you for your reply.

I changed P2.7 to P5.2 and Timer but still I don't have any thing.

 Could you please help me for solve the problem.

Best 

Elham

#include <msp430.h>
unsigned long timerBcaptureValues;

#define TB2IV_NONE          (0x0000u)    /* No Interrupt pending */
#define TB2IV_TB1CCR1       (0x0002u)    /* TB2CCR1_CCIFG */
#define TB2IV_TB1CCR2       (0x0004u)    /* TB2CCR2_CCIFG */
#define TB2IV_3             (0x0006u)    /* Reserved */
#define TB2IV_4             (0x0008u)    /* Reserved */
#define TB2IV_5             (0x000Au)    /* Reserved */
#define TB2IV_6             (0x000Cu)    /* Reserved */
#define TB2IV_TB2IFG        (0x000Eu)    /* TB2IFG */


int main(void)
{
  WDTCTL = WDTPW | WDTHOLD;                 // Stop WDT

  P1DIR |= BIT0;
  P1OUT = 0;

  P2SEL0 |= BIT2;                           // P2.7 selected as TB0CLK


  PM5CTL0 &= ~LOCKLPM5;

  // Configure Timer_B
  TB2CTL = TBSSEL_0 | MC_2 | TBCLR | TBIE;  // ACLK, count mode, clear TBR, enable interrupt
  TB2R = 0xFFFF - 20;                       // Offset until TBR overflow
  __bis_SR_register(LPM4_bits | GIE);       // Enter LPM4, enable interrupts
  __no_operation();                         // For debug

  while (1)
  {
    P1OUT ^= BIT0;                          // P1.0 = toggle
    __bis_SR_register(LPM0_bits);           // CPU is not required
  }
}

// Timer0_B3 Interrupt Vector (TBIV) handler
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=TIMER2_B1_VECTOR
__interrupt void TIMER2_B1_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(TIMER2_B1_VECTOR))) TIMER2_B1_ISR (void)
#else
#error Compiler not supported!
#endif
{
  switch(__even_in_range(TB2IV,TB2IV_TB2IFG))
  {
      case TB0IV_NONE:
          break;                             // No interrupt
      case TB0IV_TBCCR1:
          break;                             // CCR1 not used
      case TB0IV_TBCCR2:
          TB2CCTL0 &= ~CCIFG;
          timerBcaptureValues = TB2CCR0;
          TB2CCR2 += 50000;                  // Add Offset to TBCCR1
          __bic_SR_register_on_exit(LPM0_bits);// CPU active on reti
          break;                             // CCR2 not used
      case TB0IV_TBIFG:                      // overflow
          TB2CTL = TBSSEL_2 | TBCLR;         // SMCLK, clear TBR
          TB2CCTL2 = CCIE;                   // TBCCR1 interrupt enabled
          TB2CCR2 = 50000;
          TB2CTL |= MC_2;                    // Start Timer_B in continuous
          __bic_SR_register_on_exit(LPM4_bits);// Exit LPM4 on reti
          break;
      default:
          break;
  }
}

  P2SEL0 |= BIT2;                           // P2.7 selected as TB0CLK

->

  P5SEL0 |= BIT2;                           // P2.7 selected as TB0CLK

Dear Johnson

Thank you for your reply.

I changed

  P2SEL0 |= BIT2;                         

to

  P5SEL0 |= BIT2; 

but still I don't have any thing.

Best 

Elham

Hi Elham,

You can try to follo MSP430 user's guide and datasheet to debug your code in CCS.

You need to check the function selection for P5.2(PxSELx).

Thanks!

Best Regards

Johnson

There is a potential solution over in the other thread. It uses P2.2 (TB1CLK), which does have a Launchpad pin.