Hi, I'm sending SAADC data via BLE. If my SAADC_SAMPLE_RATE is high(e.g. 250ms), the code works perfectly fine. However, if I sample at a fast rate (e.g. 10ms), there will be a BLE ERROR 8 (0x8) GATT CONN TIMEOUT issue.
1) Does the error caused by BLE MTU, or SAADC dual Buffer, or something else?
2) If I set SAADC buffer = 4 and 4 channels, does that mean SAADC will save the past 4 data in the 4 channels (in total 16 data), and give return averaged data for 4 channels?
3) I use the timer to interrupt SAADC. For each interrupt, there will be only 1 SAADC reading. If SAADC_SAMPLE_RATE = 250ms and buffer = 4, does that mean SAADC returns the data at 1 second ago (250ms*4 = 1sec)?
4) BLE min/max connection interval is 10ms to 20ms. If my SAADC timer interrupts every 250ms, what data will BLE send during most of the connection intervals? Just empty packages?
5) If the BLE min/max connection interval is 10ms to 20ms, and my SAADC timer interrupts every 5ms, does that mean there will be 2-4 packets (Rx+Tx is 1 packet) for each connection interval?
6) My custom board uses an internal RC oscillator (32.768kHz), Why does SAADC uses NRF_TIMER_FREQ_31250Hz, but not 32.768kHz?
Thank you very much!
Here is my code.
#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "bsp_btn_ble.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"
#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#define APP_BLE_CONN_CFG_TAG 1 /**< A tag identifying the SoftDevice BLE configuration. */
#define DEVICE_NAME "Nordic_UART" /**< Name of device. Will be included in the advertising data. */
#define NUS_SERVICE_UUID_TYPE BLE_UUID_TYPE_VENDOR_BEGIN /**< UUID type for the Nordic UART Service (vendor specific). */
#define APP_BLE_OBSERVER_PRIO 3 /**< Application's BLE observer priority. You shouldn't need to modify this value. */
#define APP_ADV_INTERVAL 64 /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */
#define APP_ADV_DURATION 0 /**< The advertising duration (180 seconds) in units of 10 milliseconds. */
/*
The connection interval is the amount of time between two connection events
in units of 1.25 ms.
The connection interval can range from a minimum value of 6 (7.5 ms) to a maximum of 3200 (4.0 s).
e.g.
If the slave device sends connection update request MIN_CONN = 15ms and MAX_CONN = 40ms,
that means the master has freedom to choose connection interval between 15ms and 40ms.
So 30ms is normal.
*/
#define MIN_CONN_INTERVAL MSEC_TO_UNITS(10, UNIT_1_25_MS) /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL MSEC_TO_UNITS(20, UNIT_1_25_MS) /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
/*
Slave Latency gives the slave (peripheral) device the option of skipping a number of connection events.
If the peripheral does not have any data to send, it can skip connection events, stay asleep, and save power.
*/
#define SLAVE_LATENCY 0 /**< Slave latency. */
/*
Supervision Time-out is the maximum amount of time between two successful connection events.
If this time passes without a successful connection event, the device terminates the connection and returns to an unconnected state.
This parameter value is represented in units of 10 ms.
The supervision time-out value can range from a minimum of 10 (100 ms) to 3200 (32.0 s). \
The time-out must be larger than the effective connection interval.
*/
#define CONN_SUP_TIMEOUT MSEC_TO_UNITS(4000, UNIT_10_MS) /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(5000) /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(30000) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT 3 /**< Number of attempts before giving up the connection parameter negotiation. */
#define DEAD_BEEF 0xDEADBEEF /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */
#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256 /**< UART RX buffer size. */
#define SAADC_SAMPLES_IN_BUFFER 4
#define SAADC_SAMPLE_RATE 10 /**< SAADC sample rate in ms. */
BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT); /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt); /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr); /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising); /**< Advertising module instance. */
static uint16_t m_conn_handle = BLE_CONN_HANDLE_INVALID; /**< Handle of the current connection. */
static uint16_t m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3; /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
static ble_uuid_t m_adv_uuids[] = /**< Universally unique service identifier. */
{
{BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
};
volatile uint8_t state = 1;
static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(3);
static nrf_saadc_value_t m_buffer_pool[2][SAADC_SAMPLES_IN_BUFFER];
static nrf_ppi_channel_t m_ppi_channel;
static uint32_t m_adc_evt_counter;
/**@brief Function for assert macro callback.
*
* @details This function will be called in case of an assert in the SoftDevice.
*
* @warning This handler is an example only and does not fit a final product. You need to analyse
* 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(DEAD_BEEF, line_num, p_file_name);
}
/**@brief Function for initializing the timer module.
*/
static void timers_init(void)
{
ret_code_t err_code = app_timer_init();
APP_ERROR_CHECK(err_code);
}
/**@brief Function for the GAP initialization.
*
* @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
* the device. It also sets the permissions and appearance.
*/
static void gap_params_init(void)
{
uint32_t err_code;
ble_gap_conn_params_t gap_conn_params;
ble_gap_conn_sec_mode_t sec_mode;
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
err_code = sd_ble_gap_device_name_set(&sec_mode,
(const uint8_t *) DEVICE_NAME,
strlen(DEVICE_NAME));
APP_ERROR_CHECK(err_code);
memset(&gap_conn_params, 0, sizeof(gap_conn_params));
gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
gap_conn_params.slave_latency = SLAVE_LATENCY;
gap_conn_params.conn_sup_timeout = CONN_SUP_TIMEOUT;
err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling Queued Write Module errors.
*
* @details A pointer to this function will be passed to each service which may need to inform the
* application about an error.
*
* @param[in] nrf_error Error code containing information about what went wrong.
*/
static void nrf_qwr_error_handler(uint32_t nrf_error)
{
APP_ERROR_HANDLER(nrf_error);
}
/**@brief Function for handling the data from the Nordic UART Service.
*
* @details This function will process the data received from the Nordic UART BLE Service and send
* it to the UART module.
*
* @param[in] p_evt Nordic UART Service event.
*/
/**@snippet [Handling the data received over BLE] */
static void nus_data_handler(ble_nus_evt_t * p_evt)
{
if (p_evt->type == BLE_NUS_EVT_RX_DATA)
{
uint32_t err_code;
NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");
NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);
for (uint32_t i = 0; i < p_evt->params.rx_data.length; i++)
{
do
{
err_code = app_uart_put(p_evt->params.rx_data.p_data[i]);
if ((err_code != NRF_SUCCESS) && (err_code != NRF_ERROR_BUSY))
{
NRF_LOG_ERROR("Failed receiving NUS message. Error 0x%x. ", err_code);
APP_ERROR_CHECK(err_code);
}
} while (err_code == NRF_ERROR_BUSY);
}
if (p_evt->params.rx_data.p_data[p_evt->params.rx_data.length - 1] == '\r')
{
while (app_uart_put('\n') == NRF_ERROR_BUSY);
}
}
}
/**@snippet [Handling the data received over BLE] */
/**@brief Function for initializing services that will be used by the application.
*/
static void services_init(void)
{
uint32_t err_code;
ble_nus_init_t nus_init;
nrf_ble_qwr_init_t qwr_init = {0};
// Initialize Queued Write Module.
qwr_init.error_handler = nrf_qwr_error_handler;
err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
APP_ERROR_CHECK(err_code);
// Initialize NUS.
memset(&nus_init, 0, sizeof(nus_init));
nus_init.data_handler = nus_data_handler;
err_code = ble_nus_init(&m_nus, &nus_init);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling an event from the Connection Parameters Module.
*
* @details This function will be called for all events in the Connection Parameters Module
* which are passed to the application.
*
* @note All this function does is to disconnect. This could have been done by simply setting
* the disconnect_on_fail config parameter, but instead we use the event handler
* mechanism to demonstrate its use.
*
* @param[in] p_evt Event received from the Connection Parameters Module.
*/
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
uint32_t err_code;
if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
{
err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
APP_ERROR_CHECK(err_code);
}
}
/**@brief Function for handling errors from the Connection Parameters module.
*
* @param[in] nrf_error Error code containing information about what went wrong.
*/
static void conn_params_error_handler(uint32_t nrf_error)
{
APP_ERROR_HANDLER(nrf_error);
}
/**@brief Function for initializing the Connection Parameters module.
*/
static void conn_params_init(void)
{
uint32_t err_code;
ble_conn_params_init_t cp_init;
memset(&cp_init, 0, sizeof(cp_init));
cp_init.p_conn_params = NULL;
cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
cp_init.next_conn_params_update_delay = NEXT_CONN_PARAMS_UPDATE_DELAY;
cp_init.max_conn_params_update_count = MAX_CONN_PARAMS_UPDATE_COUNT;
cp_init.start_on_notify_cccd_handle = BLE_GATT_HANDLE_INVALID;
cp_init.disconnect_on_fail = false;
cp_init.evt_handler = on_conn_params_evt;
cp_init.error_handler = conn_params_error_handler;
err_code = ble_conn_params_init(&cp_init);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for putting the chip into sleep mode.
*
* @note This function will not return.
*/
static void sleep_mode_enter(void)
{
uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
APP_ERROR_CHECK(err_code);
// Prepare wakeup buttons.
err_code = bsp_btn_ble_sleep_mode_prepare();
APP_ERROR_CHECK(err_code);
// Go to system-off mode (this function will not return; wakeup will cause a reset).
err_code = sd_power_system_off();
APP_ERROR_CHECK(err_code);
}
/**@brief Function for handling advertising events.
*
* @details This function will be called for advertising events which are passed to the application.
*
* @param[in] ble_adv_evt Advertising event.
*/
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
uint32_t err_code;
switch (ble_adv_evt)
{
case BLE_ADV_EVT_FAST:
err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
APP_ERROR_CHECK(err_code);
break;
case BLE_ADV_EVT_IDLE:
sleep_mode_enter();
break;
default:
break;
}
}
/**@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)
{
uint32_t err_code;
switch (p_ble_evt->header.evt_id)
{
case BLE_GAP_EVT_CONNECTED:
NRF_LOG_INFO("Connected");
err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
APP_ERROR_CHECK(err_code);
m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
APP_ERROR_CHECK(err_code);
break;
case BLE_GAP_EVT_DISCONNECTED:
NRF_LOG_INFO("Disconnected");
// LED indication will be changed when advertising starts.
m_conn_handle = BLE_CONN_HANDLE_INVALID;
break;
case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
{
NRF_LOG_DEBUG("PHY update request.");
// Auto/1Mbps/2Mbps/Coded/not-configured
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_GAP_EVT_SEC_PARAMS_REQUEST:
// Pairing not supported
err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
APP_ERROR_CHECK(err_code);
break;
case BLE_GATTS_EVT_SYS_ATTR_MISSING:
// No system attributes have been stored.
err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0);
APP_ERROR_CHECK(err_code);
break;
case BLE_GATTC_EVT_TIMEOUT:
// Disconnect on GATT Client timeout event.
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.
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:
// No implementation needed.
break;
}
}
/**@brief Function for the SoftDevice initialization.
*
* @details This function 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 ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
{
m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
}
NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
p_gatt->att_mtu_desired_central,
p_gatt->att_mtu_desired_periph);
}
/**@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_periph_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)
{
uint32_t err_code;
switch (event)
{
case BSP_EVENT_SLEEP:
sleep_mode_enter();
break;
case BSP_EVENT_DISCONNECT:
err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
if (err_code != NRF_ERROR_INVALID_STATE)
{
APP_ERROR_CHECK(err_code);
}
break;
case BSP_EVENT_WHITELIST_OFF:
if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
{
err_code = ble_advertising_restart_without_whitelist(&m_advertising);
if (err_code != NRF_ERROR_INVALID_STATE)
{
APP_ERROR_CHECK(err_code);
}
}
break;
default:
break;
}
}
/**@brief Function for handling app_uart events.
*
* @details This function will receive a single character from the app_uart module and append it to
* a string. The string will be be sent over BLE when the last character received was a
* 'new line' '\n' (hex 0x0A) or if the string has reached the maximum data length.
*/
/**@snippet [Handling the data received over UART] */
void uart_event_handle(app_uart_evt_t * p_event)
{
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint8_t index = 0;
uint32_t err_code;
switch (p_event->evt_type)
{
case APP_UART_DATA_READY:
UNUSED_VARIABLE(app_uart_get(&data_array[index]));
index++;
if ((data_array[index - 1] == '\n') ||
(data_array[index - 1] == '\r') ||
(index >= m_ble_nus_max_data_len))
{
if (index > 1)
{
NRF_LOG_DEBUG("Ready to send data over BLE NUS");
NRF_LOG_HEXDUMP_DEBUG(data_array, index);
do
{
uint16_t length = (uint16_t)index;
err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
if ((err_code != NRF_ERROR_INVALID_STATE) &&
(err_code != NRF_ERROR_RESOURCES) &&
(err_code != NRF_ERROR_NOT_FOUND))
{
APP_ERROR_CHECK(err_code);
}
} while (err_code == NRF_ERROR_RESOURCES);
}
index = 0;
}
break;
case APP_UART_COMMUNICATION_ERROR:
APP_ERROR_HANDLER(p_event->data.error_communication);
break;
case APP_UART_FIFO_ERROR:
APP_ERROR_HANDLER(p_event->data.error_code);
break;
default:
break;
}
}
/**@snippet [Handling the data received over UART] */
/**@brief Function for initializing the UART module.
*/
/**@snippet [UART Initialization] */
static void uart_init(void)
{
uint32_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,
#if defined (UART_PRESENT)
.baud_rate = NRF_UART_BAUDRATE_115200
#else
.baud_rate = NRF_UARTE_BAUDRATE_115200
#endif
};
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);
}
/**@snippet [UART Initialization] */
/**@brief Function for initializing the Advertising functionality.
*/
static void advertising_init(void)
{
uint32_t err_code;
ble_advertising_init_t init;
memset(&init, 0, sizeof(init));
init.advdata.name_type = BLE_ADVDATA_FULL_NAME;
init.advdata.include_appearance = false;
init.advdata.flags = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
init.srdata.uuids_complete.p_uuids = m_adv_uuids;
init.config.ble_adv_fast_enabled = true;
init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
init.config.ble_adv_fast_timeout = APP_ADV_DURATION;
init.evt_handler = on_adv_evt;
err_code = ble_advertising_init(&m_advertising, &init);
APP_ERROR_CHECK(err_code);
ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}
/**@brief Function for initializing buttons and leds.
*
* @param[out] p_erase_bonds Will be true if the clear bonding button was pressed to wake the application up.
*/
static void buttons_leds_init(bool * p_erase_bonds)
{
bsp_event_t startup_event;
uint32_t 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);
*p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}
/**@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 handling the idle state (main loop).
*
* @details If there is no pending log operation, then sleep until next the next event occurs.
*/
static void idle_state_handle(void)
{
UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
nrf_pwr_mgmt_run();
}
/**@brief Function for starting advertising.
*/
static void advertising_start(void)
{
uint32_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
APP_ERROR_CHECK(err_code);
}
void timer_handler(nrf_timer_event_t event_type, void* p_context)
{
}
void saadc_sampling_event_init(void)
{
ret_code_t err_code;
err_code = nrf_drv_ppi_init();
APP_ERROR_CHECK(err_code);
nrf_drv_timer_config_t timer_config = NRF_DRV_TIMER_DEFAULT_CONFIG;
timer_config.frequency = NRF_TIMER_FREQ_31250Hz;
err_code = nrf_drv_timer_init(&m_timer, &timer_config, timer_handler);
APP_ERROR_CHECK(err_code);
/* setup m_timer for compare event */
uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer,SAADC_SAMPLE_RATE);
nrf_drv_timer_extended_compare(&m_timer, NRF_TIMER_CC_CHANNEL0, ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, false);
nrf_drv_timer_enable(&m_timer);
uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer, NRF_TIMER_CC_CHANNEL0);
uint32_t saadc_sample_event_addr = nrf_drv_saadc_sample_task_get();
/* setup ppi channel so that timer compare event is triggering sample task in SAADC */
err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_ppi_channel_assign(m_ppi_channel, timer_compare_event_addr, saadc_sample_event_addr);
APP_ERROR_CHECK(err_code);
}
void saadc_sampling_event_enable(void)
{
ret_code_t err_code = nrf_drv_ppi_channel_enable(m_ppi_channel);
APP_ERROR_CHECK(err_code);
}
void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
{
ret_code_t err_code;
uint16_t adc_value;
uint8_t value[SAADC_SAMPLES_IN_BUFFER*2];
uint16_t bytes_to_send;
// set buffers
err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAADC_SAMPLES_IN_BUFFER);
APP_ERROR_CHECK(err_code);
// print samples on hardware UART and parse data for BLE transmission
printf("ADC event number: %d\r\n",(int)m_adc_evt_counter);
for (int i = 0; i < SAADC_SAMPLES_IN_BUFFER; i++)
{
printf("%d\r\n", p_event->data.done.p_buffer[i]);
adc_value = p_event->data.done.p_buffer[i];
value[i*2] = adc_value;
value[(i*2)+1] = adc_value >> 8;
}
// Send data over BLE via NUS service. Create string from samples and send string with correct length.
uint8_t nus_string[20];
bytes_to_send = sprintf(nus_string,
"%d,%d,%d,%d",
p_event->data.done.p_buffer[0],
p_event->data.done.p_buffer[1],
p_event->data.done.p_buffer[2],
p_event->data.done.p_buffer[3]);
err_code = ble_nus_data_send(&m_nus, nus_string, &bytes_to_send, m_conn_handle);
if ((err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_NOT_FOUND))
{
APP_ERROR_CHECK(err_code);
}
m_adc_evt_counter++;
}
}
void saadc_init(void)
{
ret_code_t err_code;
nrf_drv_saadc_config_t saadc_config = NRF_DRV_SAADC_DEFAULT_CONFIG;
saadc_config.resolution = NRF_SAADC_RESOLUTION_12BIT;
nrf_saadc_channel_config_t channel_0_config =
NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN4);
channel_0_config.gain = NRF_SAADC_GAIN1_4;
channel_0_config.reference = NRF_SAADC_REFERENCE_VDD4;
nrf_saadc_channel_config_t channel_1_config =
NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN5);
channel_1_config.gain = NRF_SAADC_GAIN1_4;
channel_1_config.reference = NRF_SAADC_REFERENCE_VDD4;
nrf_saadc_channel_config_t channel_2_config =
NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN6);
channel_2_config.gain = NRF_SAADC_GAIN1_4;
channel_2_config.reference = NRF_SAADC_REFERENCE_VDD4;
nrf_saadc_channel_config_t channel_3_config =
NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN7);
channel_3_config.gain = NRF_SAADC_GAIN1_4;
channel_3_config.reference = NRF_SAADC_REFERENCE_VDD4;
err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_channel_init(0, &channel_0_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_channel_init(1, &channel_1_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_channel_init(2, &channel_2_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_channel_init(3, &channel_3_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0],SAADC_SAMPLES_IN_BUFFER);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1],SAADC_SAMPLES_IN_BUFFER);
APP_ERROR_CHECK(err_code);
}
/**@brief Application main function.
*/
int main(void)
{
bool erase_bonds;
// Initialize.
uart_init();
log_init();
timers_init();
buttons_leds_init(&erase_bonds);
power_management_init();
ble_stack_init();
gap_params_init();
gatt_init();
services_init();
advertising_init();
conn_params_init();
saadc_sampling_event_init();
saadc_init();
saadc_sampling_event_enable();
// Start execution.
printf("\r\nUART started2.\r\n");
NRF_LOG_INFO("Debug logging for UART over RTT started.");
advertising_start();
// Enter main loop.
for (;;)
{
idle_state_handle();
}
}
/**
* @}
*/
