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correct sampling rate (~29 pwm loops)

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Killorin 2025-04-24 12:52:49 -04:00
parent f9125357d0
commit ee0ac28714
1 changed files with 4 additions and 2 deletions
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6
audio.c
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@ -18,6 +18,8 @@
#define AUDIO_PWM_PERIOD 258 #define AUDIO_PWM_PERIOD 258
uint32_t gSamplingRateDivider = 29; // sampling rate divider
void configure_audio() { void configure_audio() {
// configure M0PWM2, at GPIO PF2, BoosterPack 1 header C1 pin 2 // configure M0PWM2, at GPIO PF2, BoosterPack 1 header C1 pin 2
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOG); SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOG);
@ -32,12 +34,13 @@ void configure_audio() {
PWMGenConfigure(PWM0_BASE, PWM_GEN_2, PWMGenConfigure(PWM0_BASE, PWM_GEN_2,
PWM_GEN_MODE_DOWN | PWM_GEN_MODE_NO_SYNC); PWM_GEN_MODE_DOWN | PWM_GEN_MODE_NO_SYNC);
PWMGenPeriodSet(PWM0_BASE, PWM_GEN_2, PWMGenPeriodSet(PWM0_BASE, PWM_GEN_2,
AUDIO_PWM_PERIOD); AUDIO_PWM_PERIOD);
PWMPulseWidthSet(PWM0_BASE, PWM_OUT_5, PWMPulseWidthSet(PWM0_BASE, PWM_OUT_5,
roundf((float)AUDIO_PWM_PERIOD * 0.5f)); roundf((float)AUDIO_PWM_PERIOD * 0.5f));
gSamplingRateDivider = gSystemClock / AUDIO_PWM_PERIOD / AUDIO_SAMPLING_RATE;
PWMGenIntTrigEnable(PWM0_BASE, PWM_GEN_2, PWM_INT_CNT_ZERO); PWMGenIntTrigEnable(PWM0_BASE, PWM_GEN_2, PWM_INT_CNT_ZERO);
PWMOutputState(PWM0_BASE, PWM_OUT_5_BIT, true); PWMOutputState(PWM0_BASE, PWM_OUT_5_BIT, true);
@ -45,7 +48,6 @@ void configure_audio() {
} }
uint32_t gPWMSample = 0; // PWM sample counter uint32_t gPWMSample = 0; // PWM sample counter
uint32_t gSamplingRateDivider = 20; // sampling rate divider
void PWM_ISR(void) void PWM_ISR(void)
{ {
PWMGenIntClear(PWM0_BASE, PWM_GEN_2, PWM_INT_CNT_ZERO); // clear PWM interrupt flag PWMGenIntClear(PWM0_BASE, PWM_GEN_2, PWM_INT_CNT_ZERO); // clear PWM interrupt flag