I've interfaced an ST mic eval board (STEVAL-MIC006V1) to the nRF52 dev board on the PDM interface (SDK-15.2.0) . I'm attaching the code for showing my configuration and flow of capturing data and pushing it over UART, for your reference. I just want to dump 16KHz PCM output data from RAM to serial terminal so that I can read that data from terminal (with the help of a python script) and either log the raw byte values in a .csv file or generate a wave file. I did many attempts in doing so but only got a little close to getting roughly correct data in one case (I checked by generating and playing back the .wav file, parts of it were the distorted version of my voice recording).
I think I'm loosing data on communication because when I increase the Baud rate and run a python script to count number of bytes received in 1 second, I get higher values with higher baud rate. Theoretically, if sampling rate is 16KHz and samples are 16 bit wide , I should get ~32000 bytes in 1 sec on the terminal but best I get is around 16000 bytes with very high baud rate.
Please go over my code and help me out with it.
Here, pressing button 2 starts the process of reading PDM data and converting to PCM and button 3 stops the process under bsp_event_handler(bsp_event_t event) in main.c
In nrfx_pdm_irq_handler(void) in nrfx_pdm.c, under the case nrf_pdm_event_check(NRF_PDM_EVENT_END), I am splitting the 16 bit uint16_t values into 2 8bit uint8_t integers and transmitting them over UART.
I've modified the uart_central example to incorporate pdm mic application. Please go through the files and let me know what is it that I'm doing wrong.
/**
* Copyright (c) 2016 - 2018, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include "nordic_common.h"
#include "app_error.h"
#include "app_uart.h"
#include "ble_db_discovery.h"
#include "app_timer.h"
#include "app_util.h"
#include "bsp_btn_ble.h"
#include "ble.h"
#include "ble_gap.h"
#include "ble_hci.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "nrf_sdh_soc.h"
#include "ble_nus_c.h"
#include "nrf_ble_gatt.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_ble_scan.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrfx_pdm.h"
#define APP_BLE_CONN_CFG_TAG 1 /**< Tag that refers to the BLE stack configuration set with @ref sd_ble_cfg_set. The default tag is @ref BLE_CONN_CFG_TAG_DEFAULT. */
#define APP_BLE_OBSERVER_PRIO 3 /**< BLE observer priority of the application. There is no need to modify this value. */
#define UART_TX_BUF_SIZE 4096//2048//1024//256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 4096//2048//1024//256 /**< UART RX buffer size. */
#define NUS_SERVICE_UUID_TYPE BLE_UUID_TYPE_VENDOR_BEGIN /**< UUID type for the Nordic UART Service (vendor specific). */
#define ECHOBACK_BLE_UART_DATA 0//1 /**< Echo the UART data that is received over the Nordic UART Service (NUS) back to the sender. */
BLE_NUS_C_DEF(m_ble_nus_c); /**< BLE Nordic UART Service (NUS) client instance. */
NRF_BLE_GATT_DEF(m_gatt); /**< GATT module instance. */
BLE_DB_DISCOVERY_DEF(m_db_disc); /**< Database discovery module instance. */
NRF_BLE_SCAN_DEF(m_scan); /**< Scanning Module instance. */
APP_TIMER_DEF(test_timer);
static uint16_t m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - OPCODE_LENGTH - HANDLE_LENGTH; /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
/**@brief NUS UUID. */
static ble_uuid_t const m_nus_uuid =
{
.uuid = BLE_UUID_NUS_SERVICE,
.type = NUS_SERVICE_UUID_TYPE
};
nrfx_pdm_config_t pdm_config={
.mode= (nrf_pdm_mode_t)NRF_PDM_MODE_MONO,
.edge= (nrf_pdm_edge_t)NRF_PDM_EDGE_LEFTRISING,
.pin_clk= 11,
.pin_din= 12,
.clock_freq= (nrf_pdm_freq_t)NRFX_PDM_CONFIG_CLOCK_FREQ,
.gain_l= NRF_PDM_GAIN_MAXIMUM,
.gain_r= NRF_PDM_GAIN_MAXIMUM,
.interrupt_priority = NRFX_PDM_CONFIG_IRQ_PRIORITY
};
uint16_t audio_sample_buf[sample_buf_size];
/**@brief Function for handling asserts in the SoftDevice.
*
* @details This function is called in case of an assert in the SoftDevice.
*
* @warning This handler is only an example and is not meant for the final product. You need to analyze
* how your product is supposed to react in case of assert.
* @warning On assert from the SoftDevice, the system can only recover on reset.
*
* @param[in] line_num Line number of the failing assert call.
* @param[in] p_file_name File name of the failing assert call.
*/
void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
{
app_error_handler(0xDEADBEEF, line_num, p_file_name);
}
/**@brief Function for starting scanning. */
static void scan_start(void)
{
ret_code_t ret;
ret = nrf_ble_scan_start(&m_scan);
APP_ERROR_CHECK(ret);
ret = bsp_indication_set(BSP_INDICATE_SCANNING);
APP_ERROR_CHECK(ret);
}
/**@brief Function for handling Scanning Module events.
*/
static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
ret_code_t err_code;
switch(p_scan_evt->scan_evt_id)
{
case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:
{
err_code = p_scan_evt->params.connecting_err.err_code;
APP_ERROR_CHECK(err_code);
} break;
case NRF_BLE_SCAN_EVT_CONNECTED:
{
ble_gap_evt_connected_t const * p_connected =
p_scan_evt->params.connected.p_connected;
// Scan is automatically stopped by the connection.
NRF_LOG_INFO("Connecting to target %02x%02x%02x%02x%02x%02x",
p_connected->peer_addr.addr[0],
p_connected->peer_addr.addr[1],
p_connected->peer_addr.addr[2],
p_connected->peer_addr.addr[3],
p_connected->peer_addr.addr[4],
p_connected->peer_addr.addr[5]
);
} break;
case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:
{
NRF_LOG_INFO("Scan timed out.");
scan_start();
} break;
default:
break;
}
}
/**@brief Function for initializing the scanning and setting the filters.
*/
static void scan_init(void)
{
ret_code_t err_code;
nrf_ble_scan_init_t init_scan;
memset(&init_scan, 0, sizeof(init_scan));
init_scan.connect_if_match = true;
init_scan.conn_cfg_tag = APP_BLE_CONN_CFG_TAG;
err_code = nrf_ble_scan_init(&m_scan, &init_scan, scan_evt_handler);
APP_ERROR_CHECK(err_code);
err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_UUID_FILTER, &m_nus_uuid);
APP_ERROR_CHECK(err_code);
err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_UUID_FILTER, false);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling database discovery events.
*
* @details This function is a callback function to handle events from the database discovery module.
* Depending on the UUIDs that are discovered, this function forwards the events
* to their respective services.
*
* @param[in] p_event Pointer to the database discovery event.
*/
static void db_disc_handler(ble_db_discovery_evt_t * p_evt)
{
ble_nus_c_on_db_disc_evt(&m_ble_nus_c, p_evt);
}
/**@brief Function for handling characters received by the Nordic UART Service (NUS).
*
* @details This function takes a list of characters of length data_len and prints the characters out on UART.
* If @ref ECHOBACK_BLE_UART_DATA is set, the data is sent back to sender.
*/
static void ble_nus_chars_received_uart_print(uint8_t * p_data, uint16_t data_len)
{
ret_code_t ret_val;
NRF_LOG_DEBUG("Receiving data.");
NRF_LOG_HEXDUMP_DEBUG(p_data, data_len);
for (uint32_t i = 0; i < data_len; i++)
{
do
{
ret_val = app_uart_put(p_data[i]);
if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
{
NRF_LOG_ERROR("app_uart_put failed for index 0x%04x.", i);
APP_ERROR_CHECK(ret_val);
}
} while (ret_val == NRF_ERROR_BUSY);
}
if (p_data[data_len-1] == '\r')
{
while (app_uart_put('\n') == NRF_ERROR_BUSY);
}
if (ECHOBACK_BLE_UART_DATA)
{
// Send data back to the peripheral.
do
{
ret_val = ble_nus_c_string_send(&m_ble_nus_c, p_data, data_len);
if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
{
NRF_LOG_ERROR("Failed sending NUS message. Error 0x%x. ", ret_val);
APP_ERROR_CHECK(ret_val);
}
} while (ret_val == NRF_ERROR_BUSY);
}
}
/**@brief Function for handling app_uart events.
*
* @details This function receives a single character from the app_uart module and appends it to
* a string. The string is sent over BLE when the last character received is a
* 'new line' '\n' (hex 0x0A) or if the string reaches the maximum data length.
*/
void uart_event_handle(app_uart_evt_t * p_event)
{
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint16_t index = 0;
uint32_t ret_val;
switch (p_event->evt_type)
{
/**@snippet [Handling data from UART] */
case APP_UART_DATA_READY:
UNUSED_VARIABLE(app_uart_get(&data_array[index]));
index++;
if ((data_array[index - 1] == '\n') || (index >= (m_ble_nus_max_data_len)))
{
NRF_LOG_DEBUG("Ready to send data over BLE NUS");
NRF_LOG_HEXDUMP_DEBUG(data_array, index);
do
{
ret_val = ble_nus_c_string_send(&m_ble_nus_c, data_array, index);
if ( (ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_RESOURCES) )
{
APP_ERROR_CHECK(ret_val);
}
} while (ret_val == NRF_ERROR_RESOURCES);
index = 0;
}
break;
/**@snippet [Handling data from UART] */
case APP_UART_COMMUNICATION_ERROR:
NRF_LOG_ERROR("Communication error occurred while handling UART.");
APP_ERROR_HANDLER(p_event->data.error_communication);
break;
case APP_UART_FIFO_ERROR:
NRF_LOG_ERROR("Error occurred in FIFO module used by UART.");
APP_ERROR_HANDLER(p_event->data.error_code);
break;
default:
break;
}
}
/**@brief Callback handling Nordic UART Service (NUS) client events.
*
* @details This function is called to notify the application of NUS client events.
*
* @param[in] p_ble_nus_c NUS client handle. This identifies the NUS client.
* @param[in] p_ble_nus_evt Pointer to the NUS client event.
*/
/**@snippet [Handling events from the ble_nus_c module] */
static void ble_nus_c_evt_handler(ble_nus_c_t * p_ble_nus_c, ble_nus_c_evt_t const * p_ble_nus_evt)
{
ret_code_t err_code;
switch (p_ble_nus_evt->evt_type)
{
case BLE_NUS_C_EVT_DISCOVERY_COMPLETE:
NRF_LOG_INFO("Discovery complete.");
err_code = ble_nus_c_handles_assign(p_ble_nus_c, p_ble_nus_evt->conn_handle, &p_ble_nus_evt->handles);
APP_ERROR_CHECK(err_code);
err_code = ble_nus_c_tx_notif_enable(p_ble_nus_c);
APP_ERROR_CHECK(err_code);
NRF_LOG_INFO("Connected to device with Nordic UART Service.");
break;
case BLE_NUS_C_EVT_NUS_TX_EVT:
ble_nus_chars_received_uart_print(p_ble_nus_evt->p_data, p_ble_nus_evt->data_len);
break;
case BLE_NUS_C_EVT_DISCONNECTED:
NRF_LOG_INFO("Disconnected.");
scan_start();
break;
}
}
/**@snippet [Handling events from the ble_nus_c module] */
/**
* @brief Function for handling shutdown events.
*
* @param[in] event Shutdown type.
*/
static bool shutdown_handler(nrf_pwr_mgmt_evt_t event)
{
ret_code_t err_code;
err_code = bsp_indication_set(BSP_INDICATE_IDLE);
APP_ERROR_CHECK(err_code);
switch (event)
{
case NRF_PWR_MGMT_EVT_PREPARE_WAKEUP:
// Prepare wakeup buttons.
err_code = bsp_btn_ble_sleep_mode_prepare();
APP_ERROR_CHECK(err_code);
break;
default:
break;
}
return true;
}
NRF_PWR_MGMT_HANDLER_REGISTER(shutdown_handler, APP_SHUTDOWN_HANDLER_PRIORITY);
/**@brief Function for handling BLE events.
*
* @param[in] p_ble_evt Bluetooth stack event.
* @param[in] p_context Unused.
*/
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
ret_code_t err_code;
ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;
switch (p_ble_evt->header.evt_id)
{
case BLE_GAP_EVT_CONNECTED:
err_code = ble_nus_c_handles_assign(&m_ble_nus_c, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
APP_ERROR_CHECK(err_code);
// start discovery of services. The NUS Client waits for a discovery result
err_code = ble_db_discovery_start(&m_db_disc, p_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
break;
case BLE_GAP_EVT_DISCONNECTED:
NRF_LOG_INFO("Disconnected. conn_handle: 0x%x, reason: 0x%x",
p_gap_evt->conn_handle,
p_gap_evt->params.disconnected.reason);
break;
case BLE_GAP_EVT_TIMEOUT:
if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_CONN)
{
NRF_LOG_INFO("Connection Request timed out.");
}
break;
case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
// Pairing not supported.
err_code = sd_ble_gap_sec_params_reply(p_ble_evt->evt.gap_evt.conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
APP_ERROR_CHECK(err_code);
break;
case BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST:
// Accepting parameters requested by peer.
err_code = sd_ble_gap_conn_param_update(p_gap_evt->conn_handle,
&p_gap_evt->params.conn_param_update_request.conn_params);
APP_ERROR_CHECK(err_code);
break;
case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
{
NRF_LOG_DEBUG("PHY update request.");
ble_gap_phys_t const phys =
{
.rx_phys = BLE_GAP_PHY_AUTO,
.tx_phys = BLE_GAP_PHY_AUTO,
};
err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
APP_ERROR_CHECK(err_code);
} break;
case BLE_GATTC_EVT_TIMEOUT:
// Disconnect on GATT Client timeout event.
NRF_LOG_DEBUG("GATT Client Timeout.");
err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
APP_ERROR_CHECK(err_code);
break;
case BLE_GATTS_EVT_TIMEOUT:
// Disconnect on GATT Server timeout event.
NRF_LOG_DEBUG("GATT Server Timeout.");
err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
APP_ERROR_CHECK(err_code);
break;
default:
break;
}
}
/**@brief Function for initializing the BLE stack.
*
* @details Initializes the SoftDevice and the BLE event interrupt.
*/
static void ble_stack_init(void)
{
ret_code_t err_code;
err_code = nrf_sdh_enable_request();
APP_ERROR_CHECK(err_code);
// Configure the BLE stack using the default settings.
// Fetch the start address of the application RAM.
uint32_t ram_start = 0;
err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
APP_ERROR_CHECK(err_code);
// Enable BLE stack.
err_code = nrf_sdh_ble_enable(&ram_start);
APP_ERROR_CHECK(err_code);
// Register a handler for BLE events.
NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
}
/**@brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
if (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED)
{
NRF_LOG_INFO("ATT MTU exchange completed.");
m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
NRF_LOG_INFO("Ble NUS max data length set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
}
}
/**@brief Function for initializing the GATT library. */
void gatt_init(void)
{
ret_code_t err_code;
err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
APP_ERROR_CHECK(err_code);
err_code = nrf_ble_gatt_att_mtu_central_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling events from the BSP module.
*
* @param[in] event Event generated by button press.
*/
void bsp_event_handler(bsp_event_t event)
{
ret_code_t err_code;
nrfx_err_t nrfx_code;
switch (event)
{
case BSP_EVENT_SLEEP:
nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
break;
case BSP_EVENT_DISCONNECT:
err_code = sd_ble_gap_disconnect(m_ble_nus_c.conn_handle,
BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
if (err_code != NRF_ERROR_INVALID_STATE)
{
APP_ERROR_CHECK(err_code);
}
break;
case BSP_EVENT_KEY_1:
//Start the PCM Data Stream.
nrfx_code=nrfx_pdm_start();
APP_ERROR_CHECK(nrfx_code);
if(nrfx_code==NRFX_SUCCESS)
{
NRF_LOG_INFO("PDM Data Sampling has started.");
}
break;
case BSP_EVENT_KEY_2:
//Stop the PCM Data Stream.
nrfx_code=nrfx_pdm_stop();
APP_ERROR_CHECK(nrfx_code);
if(nrfx_code==NRFX_SUCCESS)
{
NRF_LOG_INFO("PDM Data Sampling has stopped.");
}
break;
default:
break;
}
}
/**@brief Function for initializing the UART. */
static void uart_init(void)
{
ret_code_t err_code;
app_uart_comm_params_t const comm_params =
{
.rx_pin_no = RX_PIN_NUMBER,
.tx_pin_no = TX_PIN_NUMBER,
.rts_pin_no = RTS_PIN_NUMBER,
.cts_pin_no = CTS_PIN_NUMBER,
.flow_control = APP_UART_FLOW_CONTROL_DISABLED,
.use_parity = false,
.baud_rate = UART_BAUDRATE_BAUDRATE_Baud115200
};
APP_UART_FIFO_INIT(&comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_event_handle,
APP_IRQ_PRIORITY_LOWEST,
err_code);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for initializing the Nordic UART Service (NUS) client. */
static void nus_c_init(void)
{
ret_code_t err_code;
ble_nus_c_init_t init;
init.evt_handler = ble_nus_c_evt_handler;
err_code = ble_nus_c_init(&m_ble_nus_c, &init);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for initializing buttons and leds. */
static void buttons_leds_init(void)
{
ret_code_t err_code;
bsp_event_t startup_event;
err_code = bsp_init(BSP_INIT_LEDS|BSP_INIT_BUTTONS, bsp_event_handler);
APP_ERROR_CHECK(err_code);
err_code = bsp_btn_ble_init(NULL, &startup_event);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for initializing the timer. */
static void timer_init(void)
{
ret_code_t err_code = app_timer_init();
APP_ERROR_CHECK(err_code);
}
/**@brief Function for initializing the nrf log module. */
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 initializing power management.
*/
static void power_management_init(void)
{
ret_code_t err_code;
err_code = nrf_pwr_mgmt_init();
APP_ERROR_CHECK(err_code);
}
/** @brief Function for initializing the database discovery module. */
static void db_discovery_init(void)
{
ret_code_t err_code = ble_db_discovery_init(db_disc_handler);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling the idle state (main loop).
*
* @details Handles any pending log operations, then sleeps until the next event occurs.
*/
static void idle_state_handle(void)
{
if (NRF_LOG_PROCESS() == false)
{
nrf_pwr_mgmt_run();
}
}
uint32_t test_var=0;
uint32_t test_var2=0;
void buffer_event_handler(nrfx_pdm_evt_t *p_evt)
{
nrfx_err_t err_code;
if(p_evt->buffer_requested==true)
{
err_code=nrfx_pdm_buffer_set(audio_sample_buf,(uint16_t)sample_buf_size);
APP_ERROR_CHECK(err_code);
test_var++;
}
else if(p_evt->buffer_requested==false)
{
//fetch the audio data from release buffer
//test_var2++;
}
}
int main(void)
{
// Initialize.
log_init();
timer_init();
uart_init();
buttons_leds_init();
db_discovery_init();
nrfx_pdm_init(&pdm_config,(nrfx_pdm_event_handler_t)buffer_event_handler);
power_management_init();
ble_stack_init();
gatt_init();
nus_c_init();
scan_init();
// Start execution.
printf("Audio Application: PCM Data -> UART, Started\r\n");
NRF_LOG_INFO("Audio Application: PCM Data -> UART, Started.");
// Enter main loop.
for (;;)
{
idle_state_handle();
}
}
/**
* Copyright (c) 2015 - 2018, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <nrfx.h>
#include <app_uart.h>
#include <app_timer.h>
#if NRFX_CHECK(NRFX_PDM_ENABLED)
#include <nrfx_pdm.h>
#include <hal/nrf_gpio.h>
#define NRFX_LOG_MODULE PDM
#include <nrfx_log.h>
#define EVT_TO_STR(event) \
(event == NRF_PDM_EVENT_STARTED ? "NRF_PDM_EVENT_STARTED" : \
(event == NRF_PDM_EVENT_STOPPED ? "NRF_PDM_EVENT_STOPPED" : \
(event == NRF_PDM_EVENT_END ? "NRF_PDM_EVENT_END" : \
"UNKNOWN EVENT")))
/** @brief PDM interface status. */
typedef enum
{
NRFX_PDM_STATE_IDLE,
NRFX_PDM_STATE_RUNNING,
NRFX_PDM_STATE_STARTING,
NRFX_PDM_STATE_STOPPING
} nrfx_pdm_state_t;
uint32_t test_var3=0;
uint32_t begin[1000]={0},t=0;//end=0,time_diff=0;
APP_TIMER_DEF(test_timer);
/** @brief PDM interface control block.*/
typedef struct
{
nrfx_pdm_event_handler_t event_handler; ///< Event handler function pointer.
int16_t * buff_address[2]; ///< Sample buffers.
uint16_t buff_length[2]; ///< Length of the sample buffers.
nrfx_drv_state_t drv_state; ///< Driver state.
volatile nrfx_pdm_state_t op_state; ///< PDM peripheral operation state.
uint8_t active_buffer; ///< Number of currently active buffer.
uint8_t error; ///< Driver error flag.
volatile uint8_t irq_buff_request; ///< Request the next buffer in the ISR.
} nrfx_pdm_cb_t;
static nrfx_pdm_cb_t m_cb;
extern uint16_t audio_sample_buf[sample_buf_size];
uint8_t audio_uart[sample_buf_size*2];
uint16_t j=0;
uint32_t k=0;
void nrfx_pdm_irq_handler(void)
{
if (nrf_pdm_event_check(NRF_PDM_EVENT_STARTED))
{
nrf_pdm_event_clear(NRF_PDM_EVENT_STARTED);
NRFX_LOG_DEBUG("Event: %s.", EVT_TO_STR(NRF_PDM_EVENT_STARTED));
uint8_t finished_buffer = m_cb.active_buffer;
// Check if the next buffer was set before.
uint8_t next_buffer = (~m_cb.active_buffer) & 0x01;
if (m_cb.buff_address[next_buffer] ||
m_cb.op_state == NRFX_PDM_STATE_STARTING)
{
nrfx_pdm_evt_t evt;
evt.error = NRFX_PDM_NO_ERROR;
m_cb.error = 0;
// Release the full buffer if ready and request the next one.
if (m_cb.op_state == NRFX_PDM_STATE_STARTING)
{
evt.buffer_released = 0;
m_cb.op_state = NRFX_PDM_STATE_RUNNING;
}
else
{
evt.buffer_released = m_cb.buff_address[finished_buffer];
m_cb.buff_address[finished_buffer] = 0;
m_cb.active_buffer = next_buffer;
}
evt.buffer_requested = true;
m_cb.event_handler(&evt);
}
else
{
// No next buffer available. Report an error.
// Do not request the new buffer as it was already done.
if (m_cb.error == 0)
{
nrfx_pdm_evt_t const evt = {
.buffer_requested = false,
.buffer_released = NULL,
.error = NRFX_PDM_ERROR_OVERFLOW
};
m_cb.error = 1;
m_cb.event_handler(&evt);
}
}
if (m_cb.op_state == NRFX_PDM_STATE_STARTING)
{
m_cb.op_state = NRFX_PDM_STATE_RUNNING;
}
}
else if (nrf_pdm_event_check(NRF_PDM_EVENT_STOPPED))
{
nrf_pdm_event_clear(NRF_PDM_EVENT_STOPPED);
NRFX_LOG_DEBUG("Event: %s.", EVT_TO_STR(NRF_PDM_EVENT_STOPPED));
nrf_pdm_disable();
m_cb.op_state = NRFX_PDM_STATE_IDLE;
// Release the buffers.
nrfx_pdm_evt_t evt;
evt.error = NRFX_PDM_NO_ERROR;
evt.buffer_requested = false;
if (m_cb.buff_address[m_cb.active_buffer])
{
evt.buffer_released = m_cb.buff_address[m_cb.active_buffer];
m_cb.buff_address[m_cb.active_buffer] = 0;
m_cb.event_handler(&evt);
}
uint8_t second_buffer = (~m_cb.active_buffer) & 0x01;
if (m_cb.buff_address[second_buffer])
{
evt.buffer_released = m_cb.buff_address[second_buffer];
m_cb.buff_address[second_buffer] = 0;
m_cb.event_handler(&evt);
}
m_cb.active_buffer = 0;
}
else if (nrf_pdm_event_check(NRF_PDM_EVENT_END))
{
//begin[t]=app_timer_cnt_get();
t++;
nrf_pdm_event_clear(NRF_PDM_EVENT_END);
j=0;
for(uint16_t i=0;i<sizeof(audio_sample_buf)/sizeof(audio_sample_buf[0]);i++)
{
audio_uart[j]=(uint8_t)(audio_sample_buf[i]>>8);
audio_uart[j+1]=(uint8_t)audio_sample_buf[i];
app_uart_put(audio_uart[j]);
app_uart_put(audio_uart[j+1]);
j+=2;
k++;
}
//end=app_timer_cnt_get();
//time_diff=app_timer_cnt_diff_compute(end,begin);
}
if (m_cb.irq_buff_request)
{
nrfx_pdm_evt_t const evt =
{
.buffer_requested = true,
.buffer_released = NULL,
.error = NRFX_PDM_NO_ERROR,
};
m_cb.irq_buff_request = 0;
m_cb.event_handler(&evt);
}
}
//void one_sec_up()
//{
// printf("Cycle: %x\n", k);
//}
nrfx_err_t nrfx_pdm_init(nrfx_pdm_config_t const * p_config,
nrfx_pdm_event_handler_t event_handler)
{
NRFX_ASSERT(p_config);
NRFX_ASSERT(event_handler);
nrfx_err_t err_code;
if (m_cb.drv_state != NRFX_DRV_STATE_UNINITIALIZED)
{
err_code = NRFX_ERROR_INVALID_STATE;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
if (p_config->gain_l > NRF_PDM_GAIN_MAXIMUM ||
p_config->gain_r > NRF_PDM_GAIN_MAXIMUM)
{
err_code = NRFX_ERROR_INVALID_PARAM;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
m_cb.buff_address[0] = 0;
m_cb.buff_address[1] = 0;
m_cb.active_buffer = 0;
m_cb.error = 0;
m_cb.event_handler = event_handler;
m_cb.op_state = NRFX_PDM_STATE_IDLE;
nrf_pdm_clock_set(p_config->clock_freq);
nrf_pdm_mode_set(p_config->mode, p_config->edge);
nrf_pdm_gain_set(p_config->gain_l, p_config->gain_r);
nrf_gpio_cfg_output(p_config->pin_clk);
nrf_gpio_pin_clear(p_config->pin_clk);
nrf_gpio_cfg_input(p_config->pin_din, NRF_GPIO_PIN_NOPULL);
nrf_pdm_psel_connect(p_config->pin_clk, p_config->pin_din);
nrf_pdm_event_clear(NRF_PDM_EVENT_STARTED);
nrf_pdm_event_clear(NRF_PDM_EVENT_END);
nrf_pdm_event_clear(NRF_PDM_EVENT_STOPPED);
nrf_pdm_int_enable(NRF_PDM_INT_STARTED | NRF_PDM_INT_STOPPED | NRF_PDM_INT_END);
NRFX_IRQ_PRIORITY_SET(PDM_IRQn, p_config->interrupt_priority);
NRFX_IRQ_ENABLE(PDM_IRQn);
m_cb.drv_state = NRFX_DRV_STATE_INITIALIZED;
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
//app_timer_create(&test_timer,APP_TIMER_MODE_REPEATED,one_sec_up);
return err_code;
}
void nrfx_pdm_uninit(void)
{
nrf_pdm_disable();
nrf_pdm_psel_disconnect();
m_cb.drv_state = NRFX_DRV_STATE_UNINITIALIZED;
NRFX_LOG_INFO("Uninitialized.");
}
static void pdm_start()
{
m_cb.drv_state = NRFX_DRV_STATE_POWERED_ON;
nrf_pdm_enable();
nrf_pdm_event_clear(NRF_PDM_EVENT_STARTED);
nrf_pdm_task_trigger(NRF_PDM_TASK_START);
}
static void pdm_buf_request()
{
m_cb.irq_buff_request = 1;
NRFX_IRQ_PENDING_SET(PDM_IRQn);
}
nrfx_err_t nrfx_pdm_start(void)
{
app_timer_start(test_timer,APP_TIMER_TICKS(3000),NULL);
NRFX_ASSERT(m_cb.drv_state != NRFX_DRV_STATE_UNINITIALIZED);
nrfx_err_t err_code;
if (m_cb.op_state != NRFX_PDM_STATE_IDLE)
{
if (m_cb.op_state == NRFX_PDM_STATE_RUNNING)
{
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
err_code = NRFX_ERROR_BUSY;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
m_cb.op_state = NRFX_PDM_STATE_STARTING;
pdm_buf_request();
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
nrfx_err_t nrfx_pdm_buffer_set(int16_t * buffer, uint16_t buffer_length)
{
if (m_cb.drv_state == NRFX_DRV_STATE_UNINITIALIZED)
{
return NRFX_ERROR_INVALID_STATE;
}
if (m_cb.op_state == NRFX_PDM_STATE_STOPPING)
{
return NRFX_ERROR_BUSY;
}
if ((buffer == NULL) || (buffer_length > NRFX_PDM_MAX_BUFFER_SIZE))
{
return NRFX_ERROR_INVALID_PARAM;
}
nrfx_err_t err_code = NRFX_SUCCESS;
// Enter the PDM critical section.
NRFX_IRQ_DISABLE(PDM_IRQn);
uint8_t next_buffer = (~m_cb.active_buffer) & 0x01;
if (m_cb.op_state == NRFX_PDM_STATE_STARTING)
{
next_buffer = 0;
}
if (m_cb.buff_address[next_buffer])
{
// Buffer already set.
err_code = NRFX_ERROR_BUSY;
}
else
{
m_cb.buff_address[next_buffer] = buffer;
m_cb.buff_length[next_buffer] = buffer_length;
nrf_pdm_buffer_set((uint32_t *)buffer, buffer_length);
if (m_cb.drv_state != NRFX_DRV_STATE_POWERED_ON)
{
pdm_start();
}
}
NRFX_IRQ_ENABLE(PDM_IRQn);
return err_code;
}
nrfx_err_t nrfx_pdm_stop(void)
{
NRFX_ASSERT(m_cb.drv_state != NRFX_DRV_STATE_UNINITIALIZED);
nrfx_err_t err_code;
if (m_cb.op_state != NRFX_PDM_STATE_RUNNING)
{
if (m_cb.op_state == NRFX_PDM_STATE_IDLE ||
m_cb.op_state == NRFX_PDM_STATE_STARTING)
{
nrf_pdm_disable();
m_cb.op_state = NRFX_PDM_STATE_IDLE;
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
err_code = NRFX_ERROR_BUSY;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
m_cb.drv_state = NRFX_DRV_STATE_INITIALIZED;
m_cb.op_state = NRFX_PDM_STATE_STOPPING;
nrf_pdm_task_trigger(NRF_PDM_TASK_STOP);
err_code = NRFX_SUCCESS;
NRFX_LOG_INFO("Function: %s, error code: %s.", __func__, NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
#endif // NRFX_CHECK(NRFX_PDM_ENABLED)
