Hi,
I got some troubles on the communication distance between the two units which one acts as central and one acts as peripheral, I tried to adjust the BLE parameters the same as ble_app_uart example, but distance was not good compared to the units running ble_app_uart_c and ble_app_uart examples respectively.
Here is my configurations:
SDK: nRF5_SDK_15.2.0_9412b96
IDE: SEGGER Embedded Studio for ARM Release 4.30c Build 2019120200.40763 Windows x64
BOARDS: PCA10056.
Source code is base on ble_app_multirole_lesc example, and is ported to working on freeRTOS.
And we mesure the communication distance just according to the BLE_GAP_EVT_CONNECTED & BLE_GAP_EVT_DISCONNECTED event.
Could you have some comments for me to improve the communication distance?
BLE parameters:
#define LESC_DEBUG_MODE (0) /**< Set to 1 to use the LESC debug keys. The debug mode allows you to use a sniffer to inspect traffic. */ #define LESC_MITM_NC (0) /**< Use MITM (Numeric Comparison). */ #define APP_BLE_CONN_CFG_TAG (1) /**< Tag that identifies the SoftDevice BLE configuration. */ #define ADV_INTERVAL MSEC_TO_UNITS(40, UNIT_0_625_MS) #define SCAN_DURATION (0x0000) /**< Duration of the scanning in units of 10 milliseconds. If set to 0x0000, scanning continues until it is explicitly disabled. */ #define APP_ADV_DURATION MSEC_TO_UNITS(1000, UNIT_10_MS) /**< The advertising duration in units of 10 milliseconds. */ #define MIN_CONN_INTERVAL MSEC_TO_UNITS(20, UNIT_1_25_MS) /**< Minimum acceptable connection interval. */ #define MAX_CONN_INTERVAL MSEC_TO_UNITS(75, UNIT_1_25_MS) /**< Maximum acceptable connection interval. */ #define SLAVE_LATENCY (0) /**< Slave latency. */ #define CONN_SUP_TIMEOUT MSEC_TO_UNITS(4000, UNIT_10_MS) /**< Connection supervisory time-out (4 seconds). */ #define SEC_PARAMS_BOND (1) /**< Perform bonding. */ #if LESC_MITM_NC #define SEC_PARAMS_MITM (1) /**< Man In The Middle protection required. */ #define SEC_PARAMS_IO_CAPABILITIES BLE_GAP_IO_CAPS_DISPLAY_YESNO /**< Display Yes/No to force Numeric Comparison. */ #else #define SEC_PARAMS_MITM (0) /**< Man In The Middle protection required. */ #define SEC_PARAMS_IO_CAPABILITIES BLE_GAP_IO_CAPS_NONE /**< No I/O caps. */ #endif #define SEC_PARAMS_LESC (0) /**< LE Secure Connections pairing required. */ #define SEC_PARAMS_KEYPRESS (0) /**< Keypress notifications not required. */ #define SEC_PARAMS_OOB (0) /**< Out Of Band data not available. */ #define SEC_PARAMS_MIN_KEY_SIZE (7) /**< Minimum encryption key size in octets. */ #define SEC_PARAMS_MAX_KEY_SIZE (16) /**< Maximum encryption key size in octets. */ #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. */
parameters in SDK_config.h:
// <o> NRF_SDH_BLE_PERIPHERAL_LINK_COUNT - Maximum number of peripheral links. #ifndef NRF_SDH_BLE_PERIPHERAL_LINK_COUNT #define NRF_SDH_BLE_PERIPHERAL_LINK_COUNT 1 #endif // <o> NRF_SDH_BLE_CENTRAL_LINK_COUNT - Maximum number of central links. #ifndef NRF_SDH_BLE_CENTRAL_LINK_COUNT #define NRF_SDH_BLE_CENTRAL_LINK_COUNT 19 #endif // <o> NRF_SDH_BLE_TOTAL_LINK_COUNT - Total link count. // <i> Maximum number of total concurrent connections using the default configuration. #ifndef NRF_SDH_BLE_TOTAL_LINK_COUNT #define NRF_SDH_BLE_TOTAL_LINK_COUNT 20 #endif
