Write 6-Bytes data using pc-ble-driver-py with nRF52840 Dongle

[Teoh Wei Jian]

Hi,

I am a very beginner in Python and BLE. I would like to use a nRF52840 Dongle to connect to a Bluetooth Device, send 6-Bytes data in the 1401 section and also perform DFU. I tried to use nRF Connect Desktop and they are workable as below. Now, I need to use pc-ble-driver-py to perform the same actions.

I have referred to the example from Heart Rate Collector and I am able to connect to my Device successfully.

To be done:

1. Send 6 Bytes data in 1401 section.

2. Perform DFU to program product firmware.

Below are some references.

https://devzone.nordicsemi.com/f/nordic-q-a/59885/custom-128bit-uuid-operations-write-and-read-in-pc-ble-driver-py/243652#243652

 Adding custom service UUID in pc_ble_driver_py 

 Adding custom service UUID in pc_ble_driver_py problems 

[Jørgen Holmefjord]

Hi,

1. Send 6 Bytes data in 1401 section.

Did you try it out with code similar to the one I posted in the first link? Is section 1401 your own custom service?

2. Perform DFU to program product firmware.

Our command line DFU tool, nrfutil, is written on top of pc-ble-driver-py. You can have a look at the source code to see how to implement DFU in your application.

Best regards,
Jørgen

[Teoh Wei Jian]

Hi Jørgen,

I am trying for #1.

1401 is the characteristics of the BLE Device. The purpose is to write a 7-bytes value to the unit.

I have modified the script from the NUS example. I attached my script below. When I run the script I am able to connect with my BLE Device. But I am not sure where to input the 7-bytes value for the 1401 characteristics.

import sys
import time
import logging
from queue import Queue, Empty
from pc_ble_driver_py.observers import *

global config, BLEDriver, BLEAdvData, BLEEvtID, BLEAdapter, BLEEnableParams, BLEGapTimeoutSrc, BLEUUID, BLEUUIDBase, BLEConfigCommon, BLEConfig, BLEConfigConnGatt, BLEGapScanParams
from pc_ble_driver_py import config

config.__conn_ic_id__ = "NRF52"
# noinspection PyUnresolvedReferences
from pc_ble_driver_py.ble_driver import (
	BLEDriver,
	BLEAdvData,
	BLEEvtID,
	BLEEnableParams,
	BLEGapTimeoutSrc,
	BLEUUID,
	BLEUUIDBase,
	BLEGapScanParams,
	BLEConfigCommon,
	BLEConfig,
	BLEConfigConnGatt,
)

# noinspection PyUnresolvedReferences
from pc_ble_driver_py.ble_adapter import BLEAdapter

global nrf_sd_ble_api_ver
nrf_sd_ble_api_ver = config.sd_api_ver_get()

TARGET_DEV_NAME = "BLE"
CONNECTIONS = 1
CFG_TAG = 1


def init(conn_ic_id):
    # noinspection PyGlobalUndefined
    global config, BLEDriver, BLEAdvData, BLEEvtID, BLEAdapter, BLEEnableParams, BLEGapTimeoutSrc, BLEUUID, BLEUUIDBase, BLEConfigCommon, BLEConfig, BLEConfigConnGatt, BLEGapScanParams
    from pc_ble_driver_py import config

    config.__conn_ic_id__ = conn_ic_id
    # noinspection PyUnresolvedReferences
    from pc_ble_driver_py.ble_driver import (
        BLEDriver,
        BLEAdvData,
        BLEEvtID,
        BLEEnableParams,
        BLEGapTimeoutSrc,
        BLEUUID,
	BLEUUIDBase,
        BLEGapScanParams,
        BLEConfigCommon,
        BLEConfig,
        BLEConfigConnGatt,
    )

    # noinspection PyUnresolvedReferences
    from pc_ble_driver_py.ble_adapter import BLEAdapter

    global nrf_sd_ble_api_ver
    nrf_sd_ble_api_ver = config.sd_api_ver_get()


class HRCollector(BLEDriverObserver, BLEAdapterObserver):

    NUS_BASE_UUID   = BLEUUIDBase([0x0041], 0x02) # 0x02 is the type BLE_UUID_TYPE_VENDOR_BEGIN 
    NUS_RX_UUID = BLEUUID(0x1041, NUS_BASE_UUID)
    NUS_TX_UUID = BLEUUID(0x3041, NUS_BASE_UUID)

    def __init__(self, adapter):
        super(HRCollector, self).__init__()
        self.adapter = adapter
        self.conn_q = Queue()
        self.adapter.observer_register(self)
        self.adapter.driver.observer_register(self)
        self.adapter.default_mtu = 250
		
        

    def open(self):
        self.adapter.driver.open()
        if config.__conn_ic_id__ == "NRF51":
            self.adapter.driver.ble_enable(
                BLEEnableParams(
                    vs_uuid_count=10,
                    service_changed=0,
                    periph_conn_count=0,
                    central_conn_count=1,
                    central_sec_count=0,
                )
            )
        elif config.__conn_ic_id__ == "NRF52":
            gatt_cfg = BLEConfigConnGatt()
            gatt_cfg.att_mtu = self.adapter.default_mtu
            gatt_cfg.tag = CFG_TAG
            self.adapter.driver.ble_cfg_set(BLEConfig.conn_gatt, gatt_cfg)

            self.adapter.driver.ble_enable()

        self.adapter.driver.ble_vs_uuid_add(HRCollector.NUS_BASE_UUID)

    def close(self):
        self.adapter.driver.close()

    def connect_and_discover(self):
        scan_duration = 180
        params = BLEGapScanParams(interval_ms=200, window_ms=150, timeout_s=scan_duration)

        self.adapter.driver.ble_gap_scan_start(scan_params=params)

        try:
            new_conn = self.conn_q.get(timeout=scan_duration)
            self.adapter.service_discovery(new_conn)

            self.adapter.enable_notification(new_conn, HRCollector.NUS_TX_UUID)
            return new_conn
        except Empty:
            print(f"No heart rate collector advertising with name {TARGET_DEV_NAME} found.")
            return None

    def on_gap_evt_connected(
        self, ble_driver, conn_handle, peer_addr, role, conn_params
    ):
        print("New connection: {}".format(conn_handle))
        self.conn_q.put(conn_handle)

    def on_gap_evt_disconnected(self, ble_driver, conn_handle, reason):
        print("Disconnected: {} {}".format(conn_handle, reason))

    def on_gap_evt_adv_report(
        self, ble_driver, conn_handle, peer_addr, rssi, adv_type, adv_data
    ):
        if BLEAdvData.Types.complete_local_name in adv_data.records:
            dev_name_list = adv_data.records[BLEAdvData.Types.complete_local_name]

        elif BLEAdvData.Types.short_local_name in adv_data.records:
            dev_name_list = adv_data.records[BLEAdvData.Types.short_local_name]

        else:
            return

        dev_name = "".join(chr(e) for e in dev_name_list)
        address_string = "".join("{0:02X}".format(b) for b in peer_addr.addr)
        print(
            "Received advertisment report, address: 0x{}, device_name: {}".format(
                address_string, dev_name
            )
        )

        if dev_name == TARGET_DEV_NAME:
            self.adapter.connect(peer_addr, tag=CFG_TAG)

    def on_notification(self, ble_adapter, conn_handle, uuid, data):
        if len(data) > 32:
            data = "({}...)".format(data[0:10])
        print("Connection: {}, {} = {}".format(conn_handle, uuid, data))
        print("NUS_RX: " + ''.join(map(chr,data)))


def main(selected_serial_port):
    print("Serial port used: {}".format(selected_serial_port))
    driver = BLEDriver(
        serial_port=selected_serial_port, auto_flash=False, baud_rate=1000000, log_severity_level="info"
    )

    adapter = BLEAdapter(driver)
    collector = HRCollector(adapter)
    collector.open()
    conn = collector.connect_and_discover()

    if conn is not None:
        #time.sleep(1000)
        while True:
            nus_string = input("NUS string: ").encode()
            adapter.write_req(conn, HRCollector.NUS_RX_UUID, nus_string + b'\n')

    collector.close()


def item_choose(item_list):
    for i, it in enumerate(item_list):
        print("\t{} : {}".format(i, it))
    print(" ")

    while True:
        try:
            choice = int(input("Enter your choice: "))
            if (choice >= 0) and (choice < len(item_list)):
                break
        except Exception:
            pass
        print("\tTry again...")
    return choice


if __name__ == "__main__":
    logging.basicConfig(
        level="DEBUG",
        format="%(asctime)s [%(thread)d/%(threadName)s] %(message)s",
    )
    serial_port = None
    if len(sys.argv) < 2:
        print("Please specify connectivity IC identifier (NRF51, NRF52)")
        exit(1)
    init(sys.argv[1])
    if len(sys.argv) == 3:
        serial_port = sys.argv[2]
    else:
        descs = BLEDriver.enum_serial_ports()
        choices = ["{}: {}".format(d.port, d.serial_number) for d in descs]
        choice = item_choose(choices)
        serial_port = descs[choice].port
    main(serial_port)
    quit()