[AT-START-F425测评] ADC测电压

eew_xQfw2M 发表于 2022-4-25 23:04

ADC 
分辨率12 位，采样率最高 2MSPS，最多18 个通道，0~15为外部输入

转换时间：在最大时钟28MHz下，最快0.5 μs

ADC输入范围：VSSA ≤ VIN ≤ VDDA

转换优先级：抢占通道优先级高于普通通道，即使普通通道正在转换中也会被抢占，在抢占通道转换完成后，再重新进行转换（是怕普通通道转换时间太长，耽误抢占通道的时效吗？）

内部参考电压：典型值 1.2V

 

操作流程：先校准，以消除电容误差，再触发转换

 

触发源：

转换时间：

用ADC_SPT1与ADC_SPT2的CSPTx 配置各个通道（ADC_INx）的采样周期 

一次转换所需的时间(ADCCLK 的周期) = 采样时间+ 12.5

CSPTx 选择1.5周期，一次转换需要1.5+12.5=14个ADCCLK 周期。

 

转换模式：

序列模式：



抢占自动转换模式：

  

反复模式：

 

分割模式：

  

数据获取：

普通通道转换数据可通过CPU 或DMA 读取普通数据寄存器（ADC_ODT）获得。多通道连续转换时，貌似只能通过DMA来读取数据？

抢占通道数据只可通过CPU读取抢占数据寄存器读取抢占数据寄存器xx（（ADC_PDTxADC_PDTx）获得。

 

ADC channel 与 pin脚对应关系

<table style="border-collapse: collapse; width: 288px; height: 20px;" width="286">
<colgroup>
<col style="width:64pt" width="85" />
<col style="width:37pt" width="49" />
<col style="width:11pt" width="14" />
<col style="width:62pt" width="82" />
<col style="width:42pt" width="56" />
</colgroup>
<tbody>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; width:85px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:1px solid black; border-right:1px solid black; border-left:1px solid black">ADC1_IN0</td>
<td class="xl65" style="border-bottom:1px solid black; width:49px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:1px solid black; border-right:1px solid black; border-left:none">PA0</td>
<td class="xl66" rowspan="8" style="border-bottom:.7px solid black; width:14px; text-align:center; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:1px solid black; border-right:1px solid black; border-left:1px solid black">　</td>
<td class="xl65" style="border-bottom:1px solid black; width:82px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:1px solid black; border-right:1px solid black; border-left:none">ADC1_IN8</td>
<td class="xl65" style="border-bottom:1px solid black; width:56px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:1px solid black; border-right:1px solid black; border-left:none">PB0</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN1</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA1</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN9</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PB1</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN2</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA2</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN10</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC0</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN3</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA3</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN11</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC1</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN4</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA4</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN12</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC2</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN5</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA5</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN13</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC3</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN6</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA6</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN14</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC4</td>
</tr>
<tr>
<td class="xl65" style="border-bottom:1px solid black; height:18px; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:1px solid black">ADC1_IN7</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PA7</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">ADC1_IN15</td>
<td class="xl65" style="border-bottom:1px solid black; padding-top:1px; padding-right:1px; padding-left:1px; vertical-align:bottom; white-space:nowrap; border-top:none; border-right:1px solid black; border-left:none">PC5</td>
</tr>
</tbody>
</table>

 

------------------分割线---------------------

以下为2个普通通道的转换代码，通过DMA来获取ADC的转换数据

<pre>
<code>__IO uint16_t adc1_ordinary_valuetab = {0};
__IO uint16_t dma_trans_complete_flag = 0;

void DMA1_Channel1_IRQHandler(void)
{
if(dma_flag_get(DMA1_FDT1_FLAG) != RESET)
{
dma_flag_clear(DMA1_FDT1_FLAG);
dma_trans_complete_flag = 1;
}
}

static void dma_config(void)
{
dma_init_type dma_init_struct;
crm_periph_clock_enable(CRM_DMA1_PERIPH_CLOCK, TRUE);
nvic_irq_enable(DMA1_Channel1_IRQn, 0, 0);
dma_reset(DMA1_CHANNEL1);

dma_flexible_config(DMA1, FLEX_CHANNEL1, DMA_FLEXIBLE_ADC1);

dma_default_para_init(&dma_init_struct);
dma_init_struct.buffer_size = 2;
dma_init_struct.direction = DMA_DIR_PERIPHERAL_TO_MEMORY;
dma_init_struct.memory_base_addr = (uint32_t)adc1_ordinary_valuetab;
dma_init_struct.memory_data_width = DMA_MEMORY_DATA_WIDTH_HALFWORD;
dma_init_struct.memory_inc_enable = TRUE;
dma_init_struct.peripheral_base_addr = (uint32_t)&(ADC1->odt);
dma_init_struct.peripheral_data_width = DMA_PERIPHERAL_DATA_WIDTH_HALFWORD;
dma_init_struct.peripheral_inc_enable = FALSE;
dma_init_struct.priority = DMA_PRIORITY_HIGH;
dma_init_struct.loop_mode_enable = FALSE;
dma_init(DMA1_CHANNEL1, &dma_init_struct);

dma_interrupt_enable(DMA1_CHANNEL1, DMA_FDT_INT, TRUE);
dma_channel_enable(DMA1_CHANNEL1, TRUE);
}

static void gpio_config(void)
{
gpio_init_type gpio_initstructure;
crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);

gpio_default_para_init(&gpio_initstructure);
gpio_initstructure.gpio_mode = GPIO_MODE_ANALOG;
gpio_initstructure.gpio_pins = GPIO_PINS_4|GPIO_PINS_5;
gpio_init(GPIOA, &gpio_initstructure);
}

void adc_config_ch(void)
{
adc_base_config_type adc_base_struct;
crm_periph_clock_enable(CRM_ADC1_PERIPH_CLOCK, TRUE);
crm_adc_clock_div_set(CRM_ADC_DIV_6);

gpio_config();
dma_config();
adc_base_default_para_init(&adc_base_struct);
adc_base_struct.sequence_mode = TRUE;
adc_base_struct.repeat_mode = FALSE;
adc_base_struct.data_align = ADC_RIGHT_ALIGNMENT;
adc_base_struct.ordinary_channel_length = 2;
adc_base_config(ADC1, &adc_base_struct);
adc_ordinary_channel_set(ADC1, ADC_CHANNEL_4, 1, ADC_SAMPLETIME_239_5);
adc_ordinary_channel_set(ADC1, ADC_CHANNEL_5, 2, ADC_SAMPLETIME_239_5);
adc_ordinary_conversion_trigger_set(ADC1, ADC12_ORDINARY_TRIG_SOFTWARE, TRUE);

adc_dma_mode_enable(ADC1, TRUE);
adc_enable(ADC1, TRUE);
adc_calibration_init(ADC1);
while(adc_calibration_init_status_get(ADC1));
adc_calibration_start(ADC1);
while(adc_calibration_status_get(ADC1));
}

void adc_channel_sample_dma()
{
dma_trans_complete_flag = 0;
dma_config();

adc_ordinary_software_trigger_enable(ADC1, TRUE);
while(dma_trans_complete_flag == 0);
}

void get_voltage()
{
float v = 0.0f;
uint16_t adc_val = 0;

adc_channel_sample_dma();

adc_val = adc1_ordinary_valuetab;
v = (float)adc_val*3.3f/4095.0f;
LCD_printf_line(6," %.3fV",v);

adc_val = adc1_ordinary_valuetab;
v = (float)adc_val*3.3f/4095.0f;
LCD_printf_line(7," %.3fV",v);
}

void adc_test()
{
adc_config_ch();
get_voltage();
}</code></pre>

 

----------------------------------------------

最后

多通道转换时，一个通道转换完成后马上把数据拿出来，想通过CPU去把数据拿出来要怎么做呢？

 

 

<table style="border-collapse:collapse; width:157px" width="157">
<colgroup>
<col style="width:64pt" width="85" />
</colgroup>
</table>

lugl4313820 发表于 2022-4-26 08:58

可以用轮询，或者dma中断、或者用缓存。

freebsder 发表于 2022-4-26 16:36

中断吧，到了马上处理，不然可能会丢数据。

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[AT-START-F425测评] ADC测电压