想起最早玩『藍牙 BLE 』時，還是用 TI CC2541 SensorTag 。而今已經是

SensorTag2015

───

 

的了。既然是要驗證樹莓派 3 的內建『藍牙』，索性就玩新的吧！還好新的

CC2650 SensorTag User’s Guide

───

 

使用手冊大體一樣。有鑑於這是首次介紹『此物』，何不串講一些消息資訊給有興趣的讀者參考呢？

【藍牙 BLE 入門】

TI Sensor Tag and Raspberry Pi

In this tutorial, you will learn how to use Bluetooth to connect and get sensor readings from a TI CC2650 SensorTag to a Raspberry Pi

 

【內建藍牙裝置摘要】

pi@raspberrypi ~  

 

【尋找藍牙 BLE 設備】

pi@raspberrypi ~  gatttool -b 68:C9:0B:17:7E:80 --interactive
[68:C9:0B:17:7E:80][LE]> connect
Attempting to connect to 68:C9:0B:17:7E:80
Connection successful
[68:C9:0B:17:7E:80][LE]> char-write-cmd 0x24 01
[68:C9:0B:17:7E:80][LE]> char-read-hnd 0x21
Characteristic value/descriptor: 54 07 c8 09 
[68:C9:0B:17:7E:80][LE]> quit

 

【飛向雲端】

Controlling TI-CC2650 from anywhere in the world

by using BLE in combination with full-duplex real-time communication

About the author

Uffe Björklund is one of the founders and CEO of XSockets.NET and have been working with development around real-time communication since 2009.

Introduction

CC2650 from Texas Instruments is an amazing piece of hardware that enables communication over Bluetooth Low Energy (BLE) as a peripheral device to a central unit. The sensortag has a lot of services, and it would be great to be able to access them from anywhere in the world.

───

 

【派生程式庫】

IanHarvey/bluepy

bluepy

Python interface to Bluetooth LE on Linux

This is a project to provide an API to allow access to Bluetooth Low Energy devices from Python. At present it runs on Linux only; I’ve mostly developed it using a Raspberry Pi, but it will also run on x86 Debian Linux.

There is also code which uses this to talk to a TI SensorTag (www.ti.com/sensortag).

Installation

The code needs an executable bluepy-helper to be compiled from C source. This is done automatically if you use the recommended pip installation method (see below). Otherwise, you can rebuild it using the Makefile in the bluepy directory.

To install the current released version, on most Debian-based systems:

sudo apt-get install python-pip libglib2.0-dev
sudo pip install bluepy

───

 

【簡易說明】

pi@raspberrypi ~  

 

【指令使用方法】

pi@raspberrypi ~  

 

期待明天會更好的耶！！！

 

 

 

 

 

 

 

 

 

 

 

 

 

要如何驗證『藍牙』與『藍牙 BLE 』 Bluetooth Low Energy 的呢？首先翻箱倒櫃找出『藍牙虛擬鍵盤』

 

，本以為安裝了『 blueman 』之後

 

，應該一試 OK ，豈料『 Jessie 』不是『 Wheezy 』，竟然『pair』與『connect』失敗。只好查詢於『論壇』︰

[solved] jessie: bluetooth can not connect to kbd MS Wegde

───

 

卻又驚訝的發現『 bluetoothctl 』手冊如此單薄︰

BLUETOOTHCTL(1)             General Commands Manual            BLUETOOTHCTL(1)

NAME
       bluetoothctl - bluetooth control tool

SYNOPSIS
       bluetoothctl

DESCRIPTION
       bluetoothctl is bluetooth control tool

USAGE
       bluetoothctl [options]

       Help Options:
         -h, --help Show help options

       Application Options:
         -v, --version Show version information and exit
         -a, --agent=CAPABILITY Register agent handler

AUTHOR
       This   manual   page   was   written   by   Nobuhiro   Iwamatsu   <iwa‐
       matsu@debian.org>, for the Debian GNU/Linux system (but may be used  by
       others).

                                   May 2013                    BLUETOOTHCTL(1)

 

就連線上的『 help 』也如是簡約︰

pi@raspberrypi ~ $ bluetoothctl 
[NEW] Controller B8:27:EB:23:2B:C8 raspberrypi [default]
[NEW] Device 64:6E:6C:C3:5E:75 CTX-VK200
[bluetooth]# help
Available commands:
  list                       List available controllers
  show [ctrl]                Controller information
  select <ctrl>              Select default controller
  devices                    List available devices
  paired-devices             List paired devices
  power <on/off>             Set controller power
  pairable <on/off>          Set controller pairable mode
  discoverable <on/off>      Set controller discoverable mode
  agent <on/off/capability>  Enable/disable agent with given capability
  default-agent              Set agent as the default one
  scan <on/off>              Scan for devices
  info <dev>                 Device information
  pair <dev>                 Pair with device
  trust <dev>                Trust device
  untrust <dev>              Untrust device
  block <dev>                Block device
  unblock <dev>              Unblock device
  remove <dev>               Remove device
  connect <dev>              Connect device
  disconnect <dev>           Disconnect device
  version                    Display version
  quit                       Quit program
[bluetooth]# 

 

當真天下是『打』出來的，軟體是『TRY』成功的耶！！？？後來偶然在網路上發現這篇文章︰

───

 

，也許人生『經驗』老似曾相識的乎？？！！

猶記當時緊依著『古訓』︰

一個指令，一個動作。

方以『試誤法』完成連線的哩！！！

 

 

 

 

 

 

 

 

 

 

 

既然因為 UART 的問題將樹莓派 3 的速度調降，以求『藍牙』之『共存』，也已知道可能影響到『藍牙』的操作性，將如之何哉？由於

藍牙

藍牙（英語：Bluetooth），一種無線技術標準，用來讓固定與行動裝置，在短距離間交換資料，以形成個人區域網路（PAN）。其使用短波特高頻（UHF）無線電波，經由2.4至2.485 GHz的ISM頻段來進行通信^[1]。1994年由電信商愛利信（Ericsson）發展出這個技術^[2]。它最初的設計，是希望建立一個RS-232資料線的無線通訊替代版本。它能夠連結多個裝置，克服同步的問題。

藍牙技術目前由藍牙技術聯盟（SIG）來負責維護其技術標準。截至2013年為止，SIG已擁有超過20,000間公司成員，其成員的領域分布在電信、電腦、網路與消費性電子產品上^[3]。IEEE曾經將藍牙技術標準化為IEEE 802.15.1，但是這個標準已經不再繼續使用。

名稱和LOGO

藍牙（Bluetooth）一詞是斯堪的納維亞語言詞彙Blåtand/Blåtann的英語化。這個詞的來源是10世紀丹麥和挪威國王藍牙哈拉爾（丹麥語：Harald Blåtand Gormsen），借國王的綽號「Blåtand」當名稱，^[4]直接翻譯成中文爲「藍牙」（blå＝藍，tand＝牙）。在中文圈，「藍牙」又稱為「藍芽」。2006年，藍牙技術聯盟組織已將全球中文譯名統一改採直譯為「藍牙」，並註冊為該組織的註冊商標。

藍牙的標誌是盧恩字母 （Hagall，ᚼ）和 （Bjarkan，ᛒ）的組合，也就是Harald Blåtand的首字母HB的合寫。

……

藍牙4.0

• 藍牙4.0是Bluetooth SIG於2010年7月7日推出的新的規範。其最重要的特性是支援省電；
• Bluetooth 4.0，協定組成和當前主流的Bluetooth h2.x+EDR、還未普及的Bluetooth h3.0+HS不同，Bluetooth 4.0是Bluetooth從誕生至今唯一的一個綜合協定規範，
• 還提出了「低功耗藍牙」、「傳統藍牙」和「高速藍牙」三種模式。
• 其中：高速藍牙主攻資料交換與傳輸；傳統藍牙則以資訊溝通、裝置連線為重點；藍牙低功耗顧名思義，以不需占用太多頻寬的裝置連線為主。前身其實是 NOKIA開發的Wibree技術，本是作為一項專為行動裝置開發的極低功耗的移動無線通信技術，在被SIG接納並規範化之後重新命名為 Bluetooth Low Energy（後簡稱低功耗藍牙）。這三種協定規範還能夠互相組合搭配、從而實作更廣泛的應用模式，此外，Bluetooth 4.0還把藍牙的傳輸距離提升到100米以上（低功耗模式條件下）。
• 分Single mode與Dual mode。
• Single mode只能與BT4.0互相傳輸無法向下相容（與3.0/2.1/2.0無法相通）;Dual mode可以向下相容可與BT4.0傳輸也可以跟3.0/2.1/2.0傳輸
• 超低的峰值、平均和待機模式功耗，覆蓋範圍增強，最大範圍可超過100米。
• 速度：支援1Mbps資料傳輸率下的超短封包，最少8個八組位，最多27個。所有連線都使用藍牙2.1加入的減速呼吸模式（sniff subrating）來達到超低工作迴圈。
• 跳頻：使用所有藍牙規範版本通用的自適應跳頻，最大程度地減少和其他2.4 GHz ISM頻段無線技術的串擾。
• 主控制：可以休眠更長時間，只在需要執行動作的時候才喚醒。
• 延遲：最短可在3毫秒內完成連線設定並開始傳輸資料。
• 健壯性：所有封包都使用24-bit CRC校驗，確保最大程度抵禦干擾。
• 安全：使用AES-128 CCM加密演算法進行封包加密和認證。
• 拓撲：每個封包的每次接收都使用32位元尋址，理論上可連線數十億裝置；針對一對一連線最佳化，並支援星形拓撲的一對多連線；使用快速連線和斷開，資料可以在網狀拓撲內轉移而無需維持複雜的網狀網路。

藍牙4.1

• 藍牙4.1是藍牙技術聯盟於2013年底推出的新的規範，其目的是為了讓 Bluetooth Smart 技術最終成為物聯網(Internet of Everything)發展的核心動力。
• 此版本為藍牙4.0的軟體更新版本，搭載藍牙4.0裝置的終端可通過軟體更新獲得此版本。
• 對於開發人員而言，該更新是藍牙技術發展史上一項重要的進步。該更新提供了更高的靈活性和掌控度，讓開發人員能創造更具創新並催化物聯網（IOT）發展的產品。
• 支援多裝置連接。
• 智慧連接：增加設置裝置間連接頻率的支援。製造商可以對裝置設置連接進行設置，使得裝置可以更加智慧的控制裝置電量。

藍牙4.2

• 藍牙4.2是藍牙技術聯盟於2014年12月推出的新的規範。

───

 

實在是個『大規範』，而且與時變遷！根本無從說起，故於此處先列出重要的資訊來源，以備不時之需︰

【 Linux Kernel 官方藍牙之標準堆疊】

───

 

【 Debian 之藍牙指南】

BluetoothUser

Using Bluetooth in a Debian system

Introduction

We assume you have a Bluetooth adapter in your computer and a Bluetooth device (such as a mobile phone or PDA). This documents describes what you need to do to use Bluetooth to communicate with other Bluetooth devices.

The steps described below are required before you can use the services Bluetooth offers. Once you have setup Bluetooth, you can for example

• exchange data with devices, such as sending music or videos to/from your phone
• use a mobile phone to give your computer mobile internet access
• use Bluetooth peripherals with your computer, such as a Bluetooth wireless mouse

See the links below for details.

───

 

【樹莓派 3 之藍牙官方設定】

 

───

 

【目前 Jessie 之藍牙版本】

pi@raspberrypi ~  

 

【 BlueZ 5.23 之發行摘要】

───

 

同時確認當下

【藍牙mini- UART 之連接速度 115200 】

pi@raspberrypi ~ $ more /lib/systemd/system/hciuart.service
[Unit]
Description=Configure Bluetooth Modems connected by UART
ConditionPathIsDirectory=/proc/device-tree/soc/gpio@7e200000/bt_pins
Before=bluetooth.service
After=dev-ttyS0.device

[Service]
Type=forking
ExecStart=/usr/bin/hciattach /dev/ttyS0 bcm43xx 115200 noflow -

[Install]
WantedBy=multi-user.target

 

以及參考

【 man hciattach 手冊】

HCIATTACH(1)              Linux System Administration             HCIATTACH(1)

NAME
       hciattach - attach serial devices via UART HCI to BlueZ stack

SYNOPSIS
       hciattach  [-b] [-n] [-p] [-t timeout] [-s speed] [-l] [-r] tty type|id
       speed flow bdaddr

DESCRIPTION
       Hciattach is used to attach a serial UART to the Bluetooth stack as HCI
       transport interface.

OPTIONS
       -b     Send break.

       -n     Don't detach from controlling terminal.

       -p     Print the PID when detaching.

       -t timeout
              Specify an initialization timeout.  (Default is 5 seconds.)
……

 

大膽踏上征途的耶！！？？

 

 

 

 

 

 

 

 

 

 

 

 

 

 

近期閱讀 Brian Dorey 上的一篇文章︰

Raspberry Pi 3 UART Overlay Workaround

Monday 07 March 2016

With the release of the Raspberry Pi 3 the original hardware UART from the Broadcom processor has been reassigned to the Bluetooth chipset and the UART output on the GPIO pins now uses a mini-uart port. The mini-uart doesn’t have a separate clock divisor and uses the core clock frequency.

I(n) theory this shouldn’t make any difference to using the port but when the new Raspberry Pi 3 arrived we found that the boot console and serial port communications no longer worked at the baud rate specified and seemed to run approximate 1.6 times slower so a 115,200 baud rate was actually running at 72000 baud rate.

【※ 400MHz / 250MHz = 1.6 ？】

The baud rate also fluctuated according to the processor load and speed which made it unusable for any external serial devices.

We posted on the official Raspberry Pi forums https://www.raspberrypi.org/forums/viewtopic.php?f=107&t=138223 to see if it would be possible to remap the hardware UART back to the GPIO pins and one of the Raspberry Pi Engineers, PhillE has been very helpful in finding a workaround for the UART issues and wrote a device tree overlay to remap the hardware UART.

One solution posted was to add core_freq=250 to /boot/cmdline.txt which reduces the CPU speed and cripples the performance of the Raspberry Pi 3 but this retains the Bluetooth functionality, an alternative way to keep the performance but also enable the UART support is to use a device tree overlay and reconfigure the Raspberry Pi 3 to use the new overlay which maps the hardware UART back to the GPIO header.

The Raspberry Pi foundation have posted about this problem on a FAQ for the Raspberry Pi 3 on their forum: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=137932 and replied with:

“My GPIO-connected UART device is broken on Pi 3, why?
The mini-uart is now routed to GPIO14/15 as the PL011 UART is now used for bluetooth communications. The mini-uart doesn’t have a separate clock divisor and uses the core clock frequency. Changes in core clock (e.g. through throttling or idle/load frequency changes) will result in arbitrary modification of the effective baud rate. There’s no easy way around this, but as a workaround there is a pi3-disable-bt devicetree overlay in latest rpi-update firmware which reverts this change.“

───

 

不得不令人想起

《春雷早發︰樹莓派 2 Model B ︰拍照害羞篇？！》之事︰

杜甫‧空囊

翠柏苦猶食，晨霞高可餐。
世人共鹵莽，吾道屬艱難。
不爨井晨凍，無衣床夜寒。
囊空恐羞澀，留得一錢看。

───

 

那ㄟㄚㄋㄟ˙？？這將會影響很多 UART 界面之裝置！！而且所謂『 WORKAROUND 』總叫人覺得『ㄑㄇ氣』不好！！？？為什麼『 mini-uart 』會少了一個『時鐘』？？！！這樹莓派基金會當真是︰每有新品，驚嚇連連！！！果然應了古話︰

人無遠慮，必有近憂。

好事不出門，壞事傳千里。

 

既已無力回天，心想何不『降頻、共存』以求其次，豈料那篇大作的這個部份資訊，偏偏又已過時︰

Raspberry Pi 3 – Bluetooth PL011 UART (9bit on mini-UART)?

……

───

 

真真是子曰：

不曰『如之何，如之何』者，吾末如之何也已矣。

 

終究人非聖賢，孰能無過？自錯誤中學習，也是重要的方法？？？此時看來『嘗試錯誤』、『與時偕行』誠有大用哉！！！

於是乎查閱

【 rpi-firmware/overlays/README 】

# line 478
Name: pi3-disable-bt
Info: Disable Pi3 Bluetooth and restore UART0/ttyAMA0 over GPIOs 14 & 15
      N.B. To disable the systemd service that initialises the modem so it
      doesn't use the UART, use 'sudo systemctl disable hciuart'.
Load: dtoverlay=pi3-disable-bt
Params: <None>

Name: pi3-miniuart-bt
Info: Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
      UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum usable baudrate.
      N.B. It is also necessary to edit /lib/systemd/system/hciuart.server and replace ttyAMA0 with ttyS0.
Load: dtoverlay=pi3-miniuart-bt
Params: <None>

 

循言修改

【 /boot/cmdline.txt 】

dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/mmcblk0p2 kgdboc=serial0,115200 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

 

以及

【 /boot/config.txt 】

# UART issues
dtoverlay=pi3-miniuart-bt
core_freq=250

 

同時更正

【 sudo nano /lib/systemd/system/hciuart.service 】

[Unit]
Description=Configure Bluetooth Modems connected by UART
ConditionPathIsDirectory=/proc/device-tree/soc/gpio@7e200000/bt_pins
Before=bluetooth.service
After=dev-ttyS0.device

[Service]
Type=forking
ExecStart=/usr/bin/hciattach /dev/ttyS0 bcm43xx 115200 noflow -

[Install]
WantedBy=multi-user.target

 

重新開機後，果然

pi@raspberrypi ~ 

 

pi@raspberrypi ~  

 

OK 的矣。再依

 

將 USB TTL Serial 『 Loopback 』串回樹莓派︰

 

用

pi@raspberrypi ~ ＄ sudo screen /dev/ttyUSB0 115200

指令驗證 PL011 UART ︰

 

幸好一切正常的耶！！！

 

 

 

 

 

 

 

 

 

 

 

 

好像是不說自明的事，拿到樹莓派 3 後，首先就是下載最新版的 Raspbian ，讀讀 Release notes︰

Raspbian Jessie

# Release notes
2016-02-26:
  * Support added for Pi 3, including Wifi and Bluetooth
  * Option to set wifi country code added to raspi-config
2016-02-09:
  * dtb that uses mmc sdcard driver (fixes problems experienced with certain SD cards)
2016-02-03:
……

 

照說用新的 raspi-config 設定好 WiFi 國別後，

 

就該運作順暢？不過總是天不從人願！只好查之以論壇︰

RPi 3 – Very poor wifi performance

……

 

考之以 rpi-update 更新紀錄︰

# rpi-update 3月九日
firmware: vc_image: Don't mangle the pitch for deinterlace with tall …

…YUV images

See: raspberrypi/firmware#520

firmware: spdif: Allow compressed audio flag to be forced
See: raspberrypi/firmware#561

kernel: vchiq_arm: Tweak the logging output

kernel: bcm2835-sdhost: Only claim one DMA channel
kernel: bcm2835-mmc: Only claim one DMA channel
See: raspberrypi/linux#1327

kernel: Pi3 DT: Add pull-ups on the UART RX lines

kernel: config: Add module for mcp3422 ADC
See: raspberrypi/linux#1330

# WiFi 電源管理問題
kernel: brcmfmac: Disable power management
See: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=138312

kernel: serial: Take care starting a hung-

 

總算能正常工作的了！！或許 dmesg 之訊息︰

pi@raspberrypi ~  

 

仍然 讓人有點憂慮？？看來驅動程式完善還需要一點時間！！

 

假使從 iwconfig ︰

pi@raspberrypi ~  

 

以及 iw list ︰

pi@raspberrypi ~  sudo apt-get install iw

# 如果 iw list 顯示空行，那個 USB WiFi dongle 不具 IEEE802.11 相容模式。

pi@raspberrypi ~ $ iw list
Wiphy phy0
# ………
# USB WiFi dongle 提供哪些模式
	Supported interface modes:
		 * IBSS
		 * managed
		 * AP
		 * AP/VLAN
		 * WDS
# 有 monitor 模式
		 * monitor
		 * mesh point
	software interface modes (can always be added):
		 * AP/VLAN
		 * monitor
	valid interface combinations:
		 * #{ AP, mesh point } <= 8,
		   total <= 8, #channels <= 1

─ 摘自《勇闖新世界︰ W!o《卡夫卡村》變形祭︰圓局定向‧四》