About NRF_ERROR_RESOURCES

[Sawada]

Central and Peripheral are connected by BLE.

The following error may be displayed when sending BLE message multiple times to the peripheral at the same time.

>> NRF_ERROR_RESOURCES

Where can I set the value for this resource?
For example, if this resource is set to 10, does NRF_ERROR_RESOURCES not occur even if BLE transmission is performed 10 times in succession, and will it occur at the 11th time?

[Sigurd]

Hi,

The NRF_ERROR_RESOURCES error means that all the BLE buffers in the SoftDevice are full, and that you can not send any more notifications until the BLE_GATTS_EVT_HVN_TX_COMPLETE event occurs. See this link.

Try increasing NRF_SDH_BLE_GAP_EVENT_LENGTH  in sdk_config.h , it should indirectly incase the buffer size.

[Sawada]

https://devzone.nordicsemi.com/f/nordic-q-a/50193/queued-write-without-response-questions/200318#200318

Solved the problem by changing the following queue size.

static void ble_stack_init(void)
{
...

ble_cfg_t ble_cfg;

memset(&ble_cfg, 0, sizeof(ble_cfg));
ble_cfg.conn_cfg.conn_cfg_tag = APP_BLE_CONN_CFG_TAG;
ble_cfg.conn_cfg.params.gattc_conn_cfg.write_cmd_tx_queue_size = 7;

err_code = sd_ble_cfg_set(BLE_CONN_CFG_GATTC, &ble_cfg, ram_start);
APP_ERROR_CHECK(err_code);

...