【英飛凌PSoC 6 RTT開發板試用】語音識別之二:音頻采集
一. 音頻采集
原理圖
從原理圖看到有6路模擬輸入,分別對應
P10.0~P10.5, VREF為模擬參考電壓。
使用的是MAX4466的MIC，接到ADC0，如下圖所示
配置模擬采集引腳
代碼
Adc.c
#include "cy_pdl.h"
#include "cyhal.h"
#include "cybsp.h"
#include "cy_retarget_io.h"
#define VPLUS_CHANNEL_0 (P10_0)
/* Conversion factor */
#define MICRO_TO_MILLI_CONV_RATIO (1000u)
/* Acquistion time in nanosecond */
#define ACQUISITION_TIME_NS (116680u)
/* ADC Scan delay in millisecond */
#define ADC_SCAN_DELAY_MS (200u)
/*******************************************************************************
* Enumerated Types
*******************************************************************************/
/* ADC Channel constants*/
enum ADC_CHANNELS
{
CHANNEL_0 = 0,
NUM_CHANNELS
} adc_channel;
/*******************************************************************************
* Global Variables
*******************************************************************************/
/* ADC Object */
cyhal_adc_t adc_obj;
/* ADC Channel 0 Object */
cyhal_adc_channel_t adc_chan_0_obj;
/* Default ADC configuration */
const cyhal_adc_config_t adc_config = {
.continuous_scanning=false, // Continuous Scanning is disabled
.average_count=1, // Average count disabled
.vref=CYHAL_ADC_REF_VDDA, // VREF for Single ended channel set to VDDA
.vneg=CYHAL_ADC_VNEG_VSSA, // VNEG for Single ended channel set to VSSA
.resolution = 12u, // 12-bit resolution
.ext_vref = NC, // No connection
.bypass_pin = NC }; // No connection
/* Asynchronous read complete flag, used in Event Handler */
static bool async_read_complete = true;
#define NUM_SCAN (1000)
#define NUM_CHANNELS (1)
/* Variable to store results from multiple channels during asynchronous read*/
int32_t result_arr[NUM_CHANNELS * NUM_SCAN] = {0};
static void adc_event_handler(void* arg, cyhal_adc_event_t event)
{
if(0u != (event & CYHAL_ADC_ASYNC_READ_COMPLETE))
{
/* Set async read complete flag to true */
async_read_complete = true;
}
}
int adc_init(void)
{
/* Variable to capture return value of functions */
cy_rslt_t result;
/* Initialize ADC. The ADC block which can connect to the channel 0 input pin is selected */
result = cyhal_adc_init(&adc_obj, VPLUS_CHANNEL_0, NULL);
if(result != CY_RSLT_SUCCESS)
{
printf("ADC initialization failed. Error: %ld\\n", (long unsigned int)result);
CY_ASSERT(0);
}
/* ADC channel configuration */
const cyhal_adc_channel_config_t channel_config = {
.enable_averaging = false, // Disable averaging for channel
.min_acquisition_ns = ACQUISITION_TIME_NS, // Minimum acquisition time set to 1us
.enabled = true }; // Sample this channel when ADC performs a scan
/* Initialize a channel 0 and configure it to scan the channel 0 input pin in single ended mode. */
result = cyhal_adc_channel_init_diff(&adc_chan_0_obj, &adc_obj, VPLUS_CHANNEL_0,
CYHAL_ADC_VNEG, &channel_config);
if(result != CY_RSLT_SUCCESS)
{
printf("ADC first channel initialization failed. Error: %ld\\n", (long unsigned int)result);
CY_ASSERT(0);
}
/* Register a callback to handle asynchronous read completion */
cyhal_adc_register_callback(&adc_obj, &adc_event_handler, result_arr);
/* Subscribe to the async read complete event to process the results */
cyhal_adc_enable_event(&adc_obj, CYHAL_ADC_ASYNC_READ_COMPLETE, CYHAL_ISR_PRIORITY_DEFAULT, true);
printf("ADC is configured in multichannel configuration.\\r\\n\\n");
printf("Channel 0 is configured in single ended mode, connected to the \\r\\n");
printf("channel 0 input pin. Provide input voltage at the channel 0 input pin \\r\\n");
return 0;
}
int adc_samp(void)
{