Maximum performance on nrf51822 ?

[Fabien Comte]

Hello,

I work on nrf51822 with S130. I use nus service with uart_c and it's very slow (500 ms to send "abc" test string).

I am not energy limited on this application. How can i speed up ?

I have a 16 MHz quartz on my board and a 32 KHz but i use the default one (not sure the one used).

I tried to set connection times to minimum but i'm not sure if they are really used.

[Fabien Comte]

I found something,

my connection parameters look ignored

that's my values

#define MIN_CONNECTION_INTERVAL    BLE_GAP_CP_MIN_CONN_INTVL_MIN
#define MAX_CONNECTION_INTERVAL    (100 * BLE_GAP_CP_MIN_CONN_INTVL_MIN)
#define SLAVE_LATENCY              0                                 
#define SUPERVISION_TIMEOUT        MSEC_TO_UNITS(4000, UNIT_10_MS)   

that's my read back min_conn_interval = 600, max_conn_interval = 600, slave_latency = 0, conn_sup_timeout = 400

but i use the example way to give theses values:

static const ble_gap_conn_params_t m_connection_param =
{
    (uint16_t)MIN_CONNECTION_INTERVAL,   // Minimum connection
    (uint16_t)MAX_CONNECTION_INTERVAL,   // Maximum connection
    SLAVE_LATENCY,                       // Slave latency
    (uint16_t)SUPERVISION_TIMEOUT        // Supervision time-out
};

...

uint32_t err_code = sd_ble_gap_connect(&peer_addr, &m_scan_param, &m_connection_param);

and

memset(&gap_conn_params, 0, sizeof(gap_conn_params));

gap_conn_params.min_conn_interval = MIN_CONNECTION_INTERVAL;
gap_conn_params.max_conn_interval = MAX_CONNECTION_INTERVAL;
gap_conn_params.slave_latency     = SLAVE_LATENCY;
gap_conn_params.conn_sup_timeout  = SUPERVISION_TIMEOUT;

err_code = sd_ble_gap_ppcp_set(&gap_conn_params);

and i have no error returned

on BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST i receive theses values ??? min_conn_interval 65535, max_conn_interval 65535, slave_latency 0, conn_sup_timeout 65535 that provoque an error code 7 with sd_ble_gap_conn_param_update

solved, it was an order of initialisation problem.

[Stefan Birnir Sverrisson]

Hi Fabien

I do not realize if you are in a peripheral role or central role. Are you perhaps using two nRF51822 devices, both with S130, one in peripheral role and one in central role? The sd_ble_gap_connect is only supported by central. The sd_ble_gap_ppcp_set is only supported by peripheral. Can you please clarify.