Part Number: MSP430FR2311
Other Parts Discussed in Thread: MSP430FR2433
Hello,
I am currently working on a system which can measure the variable frequency (100Hz - 2MHz) of a square signal. The MCU I use for my system is a MSP430FR2311.
I found on dev.ti.com (link below) a code which can measure the frequency of a signal. This application is done with a MSP430FR2433. In this application, you put a square signal of 5kHz at the input and you can get the frequency thanks to the code.
Link of the application I found : Timer - Capture Mode
As I said, I am working with a MSP430FR2311. I checked the datasheets and modified the registers to make the code work (I didn't modify comments in my C file, so comments still talk about FR2433 device). Sadly, I can't find out why this doesn't work for me. I can build the project but nothing happens when I look at the different variables signalFreq and timerAcaptureValues (which is TimerB, I didn't modify the name of the expression), neither when I put a 5kHz signal at the input, nor when I try to use the first part of the code on the website, using the auxiliary clock as the input signal.
Can you help me figure out why my code doesn't work and help me to make it work ? You can find the C file attached.
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//***************************************************************************************
// MSP430FR24xx Demo - Timer0_A3 Capture of ACLK
//
// Description: Capture a number of periods of the ACLK clock and store them in an array.
// When the set number of periods is captured the program is trapped and the LED on
// P1.0 is toggled. At this point halt the program execution read out the values using
// the debugger.
// ACLK = REFOCLK = 32kHz, MCLK = SMCLK = default DCODIV = 1MHz.
//
// MSP430FR2433
// -----------------
// /|\| |
// | | P1.2|<-- TA0.CCI2A
// --|RST | |
// | P2.2|--> ACLK
// | |
// | P1.0|-->LED
//
//
// Wei Zhao
// Texas Instruments Inc.
// Jan 2014
// Built with IAR Embedded Workbench v6.20 & Code Composer Studio v6.0.1
//***************************************************************************************
#include <msp430.h>
#define NUMBER_TIMER_CAPTURES 20
volatile unsigned int timerAcaptureValues[NUMBER_TIMER_CAPTURES];
unsigned int timerAcapturePointer = 0;
int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
// Configure GPIO
P1DIR |= BIT0; // Set P1.0 as output
P1OUT |= BIT0; // P1.0 high
P1SEL1 |= BIT2; // TA0.CCI2A input capture pin, second function
P1REN |= BIT2; // enable internal pull-down resistor
P1OUT &= ~BIT2;
P2SEL1 |= BIT2; // Set as ACLK pin, second function
P2DIR |= BIT2;
// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5;
// Configure clock
__bis_SR_register(SCG0); // disable FLL
CSCTL3 |= SELREF__REFOCLK; // Set REFO as FLL reference source
CSCTL0 = 0; // clear DCO and MOD registers
CSCTL1 &= ~(DCORSEL_7); // Clear DCO frequency select bits first
CSCTL1 |= DCORSEL_2; // Set DCO = 4MHz
CSCTL2 = FLLD_1 + 60; // DCODIV = 2MHz
__delay_cycles(3);
__bic_SR_register(SCG0); // enable FLL
while(CSCTL7 & (FLLUNLOCK0 | FLLUNLOCK1)); // Poll until FLL is locked
CSCTL4 = SELMS__DCOCLKDIV | SELA__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz
// default DCODIV as MCLK and SMCLK source
CSCTL5 |= DIVM__1 | DIVS__2; // SMCLK = 1MHz, MCLK = 2MHz
// Timer0_A3 Setup
TB0CCTL2 |= CM_1 | CCIS_0 | CCIE | CAP | SCS;
// Capture rising edge,
// Use CCI2A=ACLK,
// Synchronous capture,
// Enable capture mode,
// Enable capture interrupt
TB0CTL |= TBSSEL_2 | MC_2 | TBCLR; // Use SMCLK as clock source, clear TA0R
// Start timer in continuous mode
__bis_SR_register(LPM0_bits | GIE);
__no_operation();
}
// Timer0_A3 CC1-2, TA Interrupt Handler
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = TIMER0_B1_VECTOR
__interrupt void TIMER0_B1_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(TIMER0_B1_VECTOR))) TIMER0_B1_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(TB0IV,TB0IV_TBIFG))
{
case TB0IV_NONE:
break; // No interrupt
case TB0IV_TBCCR1:
break; // CCR1 not used
case TB0IV_TBCCR2:
timerAcaptureValues[timerAcapturePointer++] = TB0CCR2;
if (timerAcapturePointer >= 20)
{
while (1)
{
P1OUT ^= 0x01; // Toggle P1.0 (LED)
__delay_cycles(100000);
}
}
break; // CCR2 not used
case TB0IV_TBIFG:
break; // overflow
default:
break;
}
}
Thank you by advance,
Best regards,
Ghilain