STM32F334配置双路DAC输出，DAC2硬件上监测不到输出
本帖最后由 mingshixu 于 2019-1-23 20:17 编辑各位老师，求助一个问题：
最近在学习STM32F334，想实现双路DAC独立输出，根据DEMO改的代码调试过程中，DAC1能正常输出，DAC2寄存器上能看到数据，但硬件管脚上检测不到输出电平。代码如下：
void Configure_DAC(void)
{
/*## Configuration of GPIO used by DAC channels ############################*/
__IO uint32_t wait_loop_index = 0;
/* Enable GPIO Clock */
LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_GPIOA);
/* Configure GPIO in analog mode to be used as DAC output */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_4, LL_GPIO_MODE_ANALOG);
/* Configure GPIO in analog mode to be used as DAC output */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_6, LL_GPIO_MODE_ANALOG);
/*## Configuration of DAC ##################################################*/
/* Enable DAC clock */
LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_DAC1);
LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_DAC2);
/* Select trigger source */
LL_DAC_SetTriggerSource(DAC1, LL_DAC_CHANNEL_1, LL_DAC_TRIG_SOFTWARE);
LL_DAC_SetTriggerSource(DAC2, LL_DAC_CHANNEL_1, LL_DAC_TRIG_SOFTWARE);
/* Set the data to be loaded in the data holding register */
LL_DAC_ConvertData12RightAligned(DAC1, LL_DAC_CHANNEL_1, 0x300);
LL_DAC_ConvertData12RightAligned(DAC2, LL_DAC_CHANNEL_1, 0x300);
/* Enable interruption DAC channel1 underrun */
LL_DAC_EnableIT_DMAUDR1(DAC1);
LL_DAC_EnableIT_DMAUDR1(DAC2);
/* Enable DAC channel */
LL_DAC_Enable(DAC1, LL_DAC_CHANNEL_1);
LL_DAC_Enable(DAC2, LL_DAC_CHANNEL_1);
/* Delay for DAC channel voltage settling time from DAC channel startup. */
wait_loop_index = ((LL_DAC_DELAY_STARTUP_VOLTAGE_SETTLING_US * (SystemCoreClock / (100000 * 2))) / 10);
while(wait_loop_index != 0)
{
wait_loop_index--;
}
LL_DAC_EnableTrigger(DAC1, LL_DAC_CHANNEL_1);
LL_DAC_EnableTrigger(DAC2, LL_DAC_CHANNEL_1);
}
调试时观测两路DAC的寄存器，数值都相同，但DAC2管脚上始终没有输出电平，请教各位老师，这个问题怎么查？
仔细阅读了数据手册，发现DAC2与DAC1不同的一点是：DAC2在输出端有一个switch需要配置，配置为switch_enable就可以了。
DAC2可以不输出到引脚。
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