Unable to write to peripheral

[nejcokle]

Hi,

I use sd_ble_gattc_write function to write to my peripheral with my central device. I'm sure the settings should be right but i still can't see any change on peripheral. If i connect with my mobile app i can write normally.

Peripheral is write with no response only.

My code to write characteristic:

static uint32_t writeChar (uint16_t peripheral_id,uint8_t *zelVrednost)
{
    uint32_t                 error_code   = NRF_ERROR_NOT_FOUND;
    ble_gattc_write_params_t write_params = {0};


	LOG_INFO("CHAR HANDLE WRITE: 0x%04x",gs_peripheral[peripheral_id].value_handle);

write_params.write_op = BLE_GATT_OP_WRITE_REQ;
write_params.handle = gs_peripheral[peripheral_id].value_handle;
write_params.offset = 0x0000;
write_params.len = sizeof(zelVrednost);
write_params.p_value = zelVrednost;


	LOG_DEBUG("vrednost: 0x%02x\r\n", *write_params.p_value);
if ((error_code = sd_ble_gattc_write(gs_peripheral[peripheral_id].conn_handle, &write_params)) != NRF_SUCCESS)
{
		LOG_DEBUG("(Peripheral %i) Error: 0x%x", peripheral_id, error_code);
    return error_code;
}
	else
	{
		LOG_DEBUG("Success\r\n");
	}
return error_code;
}

I set my handle when i discover service and characteristic, with this line:

gs_peripheral[peripheral_id].value_handle = gsp_ble_evt->evt.gattc_evt.params.char_disc_rsp.chars[i].handle_value;

[Carles]

Peripheral is write with no response only.

In that case you should be using:

BLE_GATT_OP_WRITE_CMD

instead of:

BLE_GATT_OP_WRITE_REQ

Carles

[nejcokle]

I tried with BLE_GATT_OP_WRITE_CMD too, but i still can't write to my peripheral.

[Carles]

If you are sure the handle is correct and the call to sd_ble_gattc_write() returns NRF_SUCCESS then the only item remaining to analyze is your peripheral. Have you tried using BLE_GATT_OP_WRITE_REQ and then waiting for a BLE_GATTC_EVT_WRITE_RSP event? inside that event the gatt_status should tell you if the write was performed correctly or not. Maybe you need to bond first.

[nejcokle]

Is there a way to check if handle value is correct? It should be, but since i tried everything (even checking the peripheral) i'm not so sure anymore...

EDIT: I am 100% sure handle is right, i used dongle to check. I still can't write with my central module, but can write with my smartphone as central just fine.

[Carles]

If you write with a WRITE_REQ from the nRF51, what do you get as an error code in the response? see my previous comment, you should check gatt_status in the response event