MSP430FR2311: TimerB PWM and comparator

Hi Ian Yeh,

Would you please share the schematic and test code so I can reproduce your issue?

BR,
Ling

Hi Ling,

I experimented with MSP430FR2311 launch pad
and amend the descrption of the figure shown above: blue one is eCOMP input (C0), red one is timerB PWM out (TB1.1)
I've checked the eCOMP output (change P2.0 to COUT), it works normally

code is as below


int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
PM5CTL0 &= ~LOCKLPM5; // Disable the GPIO power-on default high-impedance mode
// to activate previously configured port settings

PMMCTL0_H = PMMPW_H;
PMMCTL2 |= INTREFEN_1;
PMMCTL0_H = 0;


initCS(); // MCLK operates in 16MHz, SMCLK is 16MHz

/* GPIO initialization */
P2REN &= ~0b11; // disable P2.0, P2.1 pull
P2DIR |= 0b11; // output direction
P2SEL0 |= 0b11; // TB1 output
P2SEL1 &= ~0b11;


/* eCOMP initialization */
P1REN &= ~0x01; // disable P1.0 pull
P1SEL0 |= 0x01; // C0 input
P1SEL1 |= 0x01;

CPDACDATA = (7 << 8) | 50;
CPDACCTL = CPDACBUFS_0 | CPDACREFS_1 | CPDACEN_1;

CPCTL0 = CPPSEL_0 | CPNSEL_6 | CPPEN | CPNEN;
CPCTL1 = CPINV_0 | CPIES_0 | CPFLT_1 | CPFLTDLY_3 | CPMSEL_0 | CPEN_1 | CPHSEL_3 | CPIE_0 | CPIIE_0;


/* timer initialization */
TB1CTL = MC_0 | TBCLR;
TB1EX0 = 0;
TB1CTL = TBIFG_0 | TBIE_0 | ID_0 | TBSSEL_2 | CNTL_0 | TBCLGRP_0;
TB1CCR0 = 1999;

TB1CCTL1 = CCIFG_0 | COV_0 | OUT_0 | CCIE_0 | OUTMOD_7 | CAP_0 | CLLD_0 | SCS_1 | CCIS_0 | CM_0;
TB1CCTL2 = CCIFG_0 | COV_0 | OUT_0 | CCIE_0 | OUTMOD_3 | CAP_0 | CLLD_0 | SCS_1 | CCIS_0 | CM_0;

TB1CCR1 = 0;
TB1CCR2 = 0;

TB1CTL |= MC_3;


for(;;);
}


BR
Ian

Lan,

Check if the output is conflict?

PWM output P2.0 P2.1

eCOMP output P2.0

BR,

Ling 

Hi Ling,

when I checked COUT function, I've changed P2.0 to COUT and measure TB1.2 (P2.1) PWM signal, so it has no conflict
even if use TB0, the phenomenon also exists.


BR
Ianphenomenon

Lan,

Try to use TB0 and see if the phenomenon still exist?

Ling

Hi Ling,

change PWM signal to P1.6, P1.7, the waveform is shown as below

red one is PWM signal (P1.6), blue one is COUT (P2.0)

do you observe the same unpredictable phenomenon?

BR

Ian

OK,

thank you!