Posted on May 17, 2011 at 09:50Hi,
I'm trying to generate 44100Hz out of the timer3 PWM output with PCLK 48MHZ.
unfortunately, PWM frequency is too slow.
here my code:
SCU_PCLKDivisorConfig(SCU_PCLK_Div2);
SCU_PLLFactorsConfig(192, 25, 2); /* Configure Factors FPLL = 96MHz */
SCU_PLLCmd(ENABLE);
SCU_MCLKSourceConfig(SCU_MCLK_PLL);
/*init */
/* GPIO4 clock source enable */
SCU_APBPeriphClockConfig(__GPIO4, ENABLE);
SCU_APBPeriphReset(__GPIO4, DISABLE);
GPIO_DeInit(GPIO4);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_InitStructure.GPIO_Direction = GPIO_PinOutput;
GPIO_InitStructure.GPIO_Type = GPIO_Type_PushPull;
GPIO_InitStructure.GPIO_IPConnected = GPIO_IPConnected_Disable;
GPIO_InitStructure.GPIO_Alternate = GPIO_OutputAlt2;
GPIO_Init(GPIO4,&GPIO_InitStructure);
TIM_StructInit(&TIM_InitStructure);
/* 44.100 KHz generation */
TIM_InitStructure.TIM_Mode = TIM_OCM_CHANNEL_1;
TIM_InitStructure.TIM_OC1_Modes = TIM_TIMING;
TIM_InitStructure.TIM_Clock_Source = TIM_CLK_APB;
TIM_InitStructure.TIM_Prescaler =0x1;
TIM_InitStructure.TIM_Pulse_Length_1=0x220;
/* Initialize the Timer 0 */
TIM_Init (TIM0, &TIM_InitStructure);
TIM_StructInit(&TIM_InitStructure);
/* PWM configuration */
TIM_InitStructure.TIM_Mode = TIM_PWM;
TIM_InitStructure.TIM_Clock_Source = TIM_CLK_APB;
TIM_InitStructure.TIM_Prescaler =0x0;
TIM_InitStructure.TIM_Pulse_Level_1 = TIM_HIGH;
TIM_InitStructure.TIM_Period_Level = TIM_LOW;
TIM_InitStructure.TIM_Pulse_Length_1 =0xff;
TIM_InitStructure.TIM_Full_Period =0x300;
/* Initialize the Timer 3 */
TIM_Init (TIM3, &TIM_InitStructure);
void TIM0_IRQHandler(void)
{
Pulse +=0x220;
TIM_SetPulse(TIM3, TIM_PWM_OC1_Channel,sample);
/* Set the TIM0 OC1 value */
TIM_SetPulse(TIM0, TIM_PWM_OC1_Channel, Pulse);
/* Clear the TIM OC1 flag */
TIM_ClearFlag(TIM0, TIM_FLAG_OC1);
}
If there is something I'm doing wrong, please direct me with the right direction (code).
Thank you in advance,
