转贴“终于用PWM做成了DA ”，运行于深圳英蓓特公司STM32评估板STM103V100_EMSTMV1
终于用PWM做成了DAa_bb 发表于 2008-3-31 16:40 ST MCU ←返回版面 举报该贴
首先谢谢各位的建议与支持，感谢ing，当然也离不开自己的探索！
之前不能得到正确的波形，主要是混淆了PWM频率和信号的采样频率，错误地使用了用DAC做输出时的8K频率，导致滤波电路无法正常工作.
以下的程序我使用TIMER4 channel3作为PWM输出，并使用TIMER2做8K定时去更新PWM占空比，输出了1KHz的正弦波。
/* ---------------------------------------------------------------
TIM4 Configuration: Output Compare Inactive Mode:
TIM4CLK = 72 MHz, Prescaler = 0, TIM2 counter clock = 72 KHz
TIM4 frequency = TIM4CLK/(TIM1_Period + 1) = 70 KHz
--------------------------------------------------------------- */
void TIMER4_Configuration(void)
{
TIM_TimeBaseInitTypeDefTIM_TimeBaseStructure;
TIM_OCInitTypeDefTIM_OCInitStructure;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 1023;
TIM_TimeBaseStructure.TIM_Prescaler = 0x00;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_Channel = TIM_Channel_3;
TIM_OCInitStructure.TIM_Pulse = 512;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInit(TIM4, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM4, ENABLE);
/* TIM4 enable counter */
TIM_Cmd(TIM4, ENABLE);
}
void TIMER2_Configuration(void)
{
TIM_TimeBaseInitTypeDefTIM_TimeBaseStructure;
TIM_OCInitTypeDefTIM_OCInitStructure;
/* ---------------------------------------------------------------
TIM2 Configuration: Output Compare Inactive Mode:
TIM2CLK = 72 MHz, Prescaler = 1000, TIM2 counter clock = 72 KHz
TIM2 frequency = TIM2CLK/(TIM2_Period + 1) = 8KHz
--------------------------------------------------------------- */
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 8;
TIM_TimeBaseStructure.TIM_Prescaler = 1000-1;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
/* Prescaler configuration */
//TIM_PrescalerConfig(TIM2, 1000-1, TIM_PSCReloadMode_Immediate);
/* Output Compare Active Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Inactive;
TIM_OCInitStructure.TIM_Channel = TIM_Channel_1;
TIM_OCInitStructure.TIM_Pulse = 8;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInit(TIM2, &TIM_OCInitStructure);
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM2, ENABLE);
/* TIM IT enable */
TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);
/* Set PC.06, PC.07, PC.08 and PC.09 pins */
GPIO_SetBits(GPIOC, GPIO_Pin_6);
/* TIM2 enable counter */
TIM_Cmd(TIM2, ENABLE);
}
u16 SINDATA=
{
512,874,1024,874,
512,149,0,149
};
/*******************************************************************************
* Function Name: TIM2_IRQHandler
* Description : This function handles TIM2 global interrupt request.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void TIM2_IRQHandler(void)
{
static u16 i=0;
static u8 j=0;
if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
{
/* Clear TIM2 Capture Compare1 interrupt pending bit*/
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
}
if(i==0)
{
i = 1;
GPIO_ResetBits(GPIOC, GPIO_Pin_6);
}
else
{
i = 0;
GPIO_SetBits(GPIOC, GPIO_Pin_6);
}
///* Set the Pulse value */
TIM4->CCR3 = SINDATA;
if(j == 8)j = 0;
} 赞一个 能不能在万利的板子上搞这个啊?
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