Hello,
I am using the Nordic PDM library to collect data from a digital microphone. I am currently storing the data in a 1k int16_t buffer and attempting to store the data in the flash to offload it. What would be the best way to output the PCM data to the computer from the buffer?
#include <stdio.h>
#include "boards.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "nrf_drv_twi.h"
#include "nrfx_pdm.h"
#include "nrf_pdm.h"
#include "nrfx_gpiote.h"
#include "nrf_fstorage.h"
#include "nrf_fstorage_nvmc.h"
#include "nrf_cli.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#define _pin_clk NRF_GPIO_PIN_MAP(0,5)
#define _pin_din NRF_GPIO_PIN_MAP(0,6)
uint16_t buffsize = 2048;
int16_t buff1[2048];
int16_t buff2[2048];
bool flag = 0;
bool writeFlag = 0;
uint32_t page = 0x00080000;
static void fstorage_evt_handler(nrf_fstorage_evt_t * p_evt);
NRF_FSTORAGE_DEF(nrf_fstorage_t fstorage) =
{
/* Set a handler for fstorage events. */
.evt_handler = fstorage_evt_handler,
/* These below are the boundaries of the flash space assigned to this instance of fstorage.
* You must set these manually, even at runtime, before nrf_fstorage_init() is called.
* The function nrf5_flash_end_addr_get() can be used to retrieve the last address on the
* last page of flash available to write data. */
.start_addr = 0x80000,
.end_addr = 0xFFFFF,
};
//#define ENABLE_LOOPBACK_TEST /**< if defined, then this example will be a loopback test, which means that TX should be connected to RX to get data loopback. */
#define MAX_TEST_DATA_BYTES (15U) /**< max number of test bytes to be used for tx and rx. */
#define UART_TX_BUF_SIZE 1024 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1024 /**< UART RX buffer size. */
#ifdef ENABLE_LOOPBACK_TEST
/* Use flow control in loopback test. */
#define UART_HWFC APP_UART_FLOW_CONTROL_ENABLED
/** @brief Function for setting the @ref ERROR_PIN high, and then enter an infinite loop.
*/
static void show_error(void)
{
bsp_board_leds_on();
while (true)
{
// Do nothing.
}
}
/** @brief Function for testing UART loop back.
* @details Transmitts one character at a time to check if the data received from the loopback is same as the transmitted data.
* @note @ref TX_PIN_NUMBER must be connected to @ref RX_PIN_NUMBER)
*/
static void uart_loopback_test()
{
uint8_t * tx_data = (uint8_t *)("\r\nLOOPBACK_TEST\r\n");
uint8_t rx_data;
// Start sending one byte and see if you get the same
for (uint32_t i = 0; i < MAX_TEST_DATA_BYTES; i++)
{
uint32_t err_code;
while (app_uart_put(tx_data[i]) != NRF_SUCCESS);
nrf_delay_ms(10);
err_code = app_uart_get(&rx_data);
if ((rx_data != tx_data[i]) || (err_code != NRF_SUCCESS))
{
show_error();
}
}
return;
}
#else
/* When UART is used for communication with the host do not use flow control.*/
#define UART_HWFC APP_UART_FLOW_CONTROL_DISABLED
#endif
static void fstorage_evt_handler(nrf_fstorage_evt_t * p_evt)
{
if (p_evt->result != NRF_SUCCESS)
{
NRF_LOG_INFO("--> Event received: ERROR while executing an fstorage operation.");
return;
}
switch (p_evt->id)
{
case NRF_FSTORAGE_EVT_WRITE_RESULT:
{
NRF_LOG_INFO("--> Event received: wrote %d bytes at address 0x%x.",
p_evt->len, p_evt->addr);
} break;
case NRF_FSTORAGE_EVT_ERASE_RESULT:
{
NRF_LOG_INFO("--> Event received: erased %d page from address 0x%x.",
p_evt->len, p_evt->addr);
} break;
default:
break;
}
}
static void drv_pdm_hand(const nrfx_pdm_evt_t *evt){
nrfx_err_t rc = 0;
if((*evt).buffer_released){
if(writeFlag){
if(!flag){
rc = nrf_fstorage_write(&fstorage, page, buff2, sizeof(buff2), NULL);
APP_ERROR_CHECK(rc);
writeFlag = 0;
}
else{
rc = nrf_fstorage_write(&fstorage, page, buff1, sizeof(buff1), NULL);
APP_ERROR_CHECK(rc);
writeFlag = 0;
}
page += 4096;
}
}
if((*evt).buffer_requested){
if(!flag){
rc = nrfx_pdm_buffer_set(buff1, buffsize);
flag = 1;
writeFlag = 1;
//error = nrfx_pdm_start();
}
else{
rc = nrfx_pdm_buffer_set(buff2, buffsize);
flag = 0;
writeFlag = 1;
//error = nrfx_pdm_start();
}
}
}
static void audio_init()
{
ret_code_t err;
nrfx_pdm_config_t config1 = NRFX_PDM_DEFAULT_CONFIG(_pin_clk, _pin_din);
nrf_pdm_enable();
err = nrfx_pdm_init(&config1, drv_pdm_hand);
APP_ERROR_CHECK(err);
err = nrfx_pdm_start();
APP_ERROR_CHECK(err);
}
static void log_init(void)
{
ret_code_t err_code = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEFAULT_BACKENDS_INIT();
}
/**
* @brief Function for main application entry.
*/
int main(void)
{
ret_code_t rc;
log_init();
NRF_LOG_INFO("PDM STARTED");
nrf_fstorage_api_t * p_fs_api;
p_fs_api = &nrf_fstorage_nvmc;
rc = nrf_fstorage_init(&fstorage, p_fs_api, NULL);
APP_ERROR_CHECK(rc);
audio_init();
// This part of the example is just for testing the loopback .
while (true)
{
//NRF_LOG_FLUSH();
/*for(size_t i = 0; i < buffsize; i++){
NRF_LOG_INFO("%d",buff1[i]);
NRF_LOG_FLUSH();
}*/
}
}
/** @} */
