为了避免程序死机，嵌入式软件开发通常会在应用程序中添加看门狗。nordic SDK12.3中，空中升级未添加重启时间设置，就更需要通过看门狗来实现重启功能。本文讲解了如何在nrf51822 SDk12.3 DFU空中升级中添加看门狗WDT

该设计项目是一款体积小的低功耗蓝牙开发板设计，它集成了测量模块，以提供实时的能量消耗数据，这对于开发人员优化软件以设计长电池寿命设备至关重要。它支持带有便于使用的 C/C++ SDK 和大量的开源库的 ARM mbed cloud-based IDE，这使得原型开发非常容易。 通过其模块化设计，我们可以将其分为两部分 - CMSIS DAP 接口部分和 BLE 部分。CMSIS DAP 接口设计就像瑞士军刀多功能组合一样。它提供模块化编程，CMSIS DAP 调试，USB 虚拟串口，电流测量和电池充电。BLE 部分建立在 Nordic nRF51822 上，Nordic nRF51822 搭载蓝牙低功耗 2.4GHz 多协议无线电，运行 16MHz 的 32 位 ARM Cortex-M0 内核，和具有 3D 加速度计和 3D 陀螺仪的 6 自由度的 MPU6050。这些集成在一起，能提供运动检测功能。蓝牙低功耗 nRF51822 开发板PCB截图: 特性: nRF51822 : ARM Cortex-M0 + 2.4GHz 无线电 (BLE 或 ANT+) MPU-6050 : 3d 加速度计 + 3d 陀螺仪 LPC11U35FHI33 : CMSIS DAP 电流测定 CN3065 : USB部分的电池充电端 电源 : USB/battery(3.5-4.2V) 输入电压:3.3V 4个 I/O 口, 全部可用作模拟输入，数字输入/输出，I2C，SPI 或 UART VCC 输出控制 硬件: 微控制器:nRF51822QFAA; LPC11U35FHI33 PCB外形尺寸:43.3mm x 29.0mm x 4.3mm 电源:USB/Battery (JST-1.0 电池座)

Adafruit_BluefruitLE_nRF51, 基于nRF51822的Adafruit Bluefruit模块库 这里库适用于所有基于nRF51或者UART的Adafruit Bluefruit模块。当前基于nRF51的Bluefruit产品包括：Bluefruit LE朋友Bluefruit LE UART朋友Bluefruit SPI朋

青风教你学蓝牙 使用nrf51822温湿度测量Nordic Ble4.0

nRF51822上手指南，非常详细的入门文档，手把手的教你入门。

nRF51-DK 开发板的原理图和PCB 官网的开发板资料，使用51系列

nrf51822的普通gpio实现串口打印功能。串口波特率是9600 停止位1 数据位8 无校验 。

nrf51822中文参考手册，nRF51822 是一款集成nRF51x系列无线收发器的超低功耗的片上系统 (Soc) ， 包含一个32位ARM Cortex-M0 CPU ， flash 存储器和模拟、数字外设。NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 Liability disclaimer Nordic Semiconductor ASa reserves the right to make changes without further notice to the product to improve reliability, function or design. Nordic Semiconductor asa does not assume any liability arising out of the application or use of any product or circuits described herein ife support applications Nordic Semiconductor's products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Nordic Semiconductor ASa customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Nordic Semiconductor ASA for any damages resulting from such improper use or sale Contact details Foryournearestdistributorpleasevisitwww.nordicsemi.com Information regarding product updates, downloads, and technical support can be accessed through your My Page account on our home page Main office: Otto Nielsens veg 12 Mailing address: Nordic Semiconductor 7052 Trondheim P.O. Box 2336 Norway 7004 Trondhe Phone:+4772898900 Norway 4772898989 画N远 NS-EN ISO 9001 CERTIFICATEDFIRM RoHS and reach statement Nordic semiconductor's products meet the requirements of Directive 2002/95/EC of the European Parliament and of the Council on the restriction of Hazardous Substances(roHS)and the requirements of the reach regulation(EC 1907/2006)on Registration, Evaluation, Authorization and Restriction of Chemicals. The SvHC(Substances of Very High Concern) candidate list is continually being updated Complete hazardous substance reports material composition reports and latest version of nordics reach statementcanbefoundonourwebsitewww.nordicsemicom Page 2 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 Datasheet status Status Description Objective Product Specification(OPS) This product specification contains target specifications for product development Preliminary Product Specification(PPS) This product specification contains preliminary data; supplementary data may be published from Nordic Semiconductor ASA later This product specification contains final product specifications. Nordic Product Specification(PS) Semiconductor ASA reserves the right to make changes at any time without notice in order to improve design and supply the best possible product. Revision History D ate Version Description May 2013 1.3 Updated schematics and boms in Section 11. 3 on page 61 April 2013 1.2 Added chip variant nRF51822-CEAA Updated feature list on front page Updated Section 3. 2. 1 on page 15, Section 3. 2. 2 on page 15, Chapter 6 on page 28, Section 10.4 on page 52, and Section 10.5.1 on page 53 Added Section 2.2.2 on page 10, Section 7. 1 on page 29, Section 9. 2 on page 50, and Section 11. 3 on page 61 Removed PCB layouts in Chapter 11 on page 54 March 2013 1.1 Added chip variant nRF51822-QFAB Added 32 MHz crystal oscillator feature. Updated feature list on front page moved subsection Calculating current when the DC/DC converter is enabled from chapter 8 to the nrF51 Refere pda Chapter 1 on page 6, Section 2.2 on page 8, Section 3. 2 on page 14 Section 3. 5 on page 18, Section 3.5.1 on page 19, Section 4. 2 on page 23, Chapter 5 on page 26, Section 8. 1 on page 30, Section 8. 1. 2 on page 31, Section 8.1.5on page 33, Section 8.2 on page 35, Section 8.3 on page 37, Section 8.5.3 on page 39, Section 8.8 on page 43, Section 8.9 on page 44, Section 8 10 on page 45, Section 8 14 on page 46, Chapter 10 on page 51, Section 11.2.3 on page 59, Section 11. 2. 1 on page 55, and Section 11.2.2 on page 57. Added Section 3.5.4 on page 21, Section 8. 1. 3 on page 32, and Section 11.1 on age 54 November 2012 1.0 Changed from PpS to PS Updated feature list on front page Updated Table 13 on page 28, Table 14 on page 29, Table 16 on page 31 Table 18 on page 33, Table 19 on page 33, Table 20 on page 34, Table 23 on page 36, Table 24 on page 37, Table 26 on page 38, Table 27 on page 38, Table 28 on page 39, Table 32 on page 42, ble 33 on page 43, Table 35 on page 44, Table 38 on page 45 Table 39 on page 46, Table 42 on page 47, Table 45 on page 48, Table 46 on page 48, Table 61 on page 53 d Figure 15 on page 59 Page 3 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 Table of contents 2 2.1 6778 2.2 3.2 中·卓 141 3.3 16 3.4 17 3.5 18 3.6 21 3.7 非音 21 4 22 4.1 …22 4.2 …23 4.3 23 4.4 23 4.5 23 4.6 23 4.7 影看非非非是非。垂 24 4.8 中中中中中中中中中中中中中中中中中中 .24 4.9 ……1.4 4.10 24 4.11 25 4.12 25 4.13 25 26 6 28 n29 7.1 29 8 。0。看0。。。。看0·。。。0春。0。。。。·000。。。0。。。。。00。看0。自。。。看0。。0。0。。 30 8.1 .30 8.2 35 8.3 37 8.4 非非着音非非非自非n非是非日非 37 8.5 春·垂看着垂垂D看看看是看 垂看春着垂是垂音垂 38 8.6 42 8.7 42 8.8 43 8.9 44 8.10 …45 8.11 245 8.12 46 8.13 46 8.14 ,46 Page 4 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 8.15 4中非·非非非中非非非 47 8.16 247 8.17 …47 8.18 48 8.19 48 8.20 48 ···命···春春··春春·春春a·春·命春d.春春··命春春 49 49 9.2 51 10.1 51 10.2 非串串 垂自, 自音。 10.3 55 10.4 52 10.5 非。自B非1非音BB省;自指自自自香自音:着 53 54 11.1 154 11.2 55 11.3 61 12 67 Page 5 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 n RF51 Reference Manual 1.2 Luci da console onso⊥as bold emi-bold Connect(Time Out, AdvInterval Connect will be written as Connect(ox00F0, Interval) Page 6 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 2 nRF5 ODE (P0.0-P031) lave AHB-LITE BUS E AHB TO APB ARM BRIDGE CORTEX-MO SWCLK DAP BBB NVIC RESET POWER NVMC WDT RADIO ANT1 AISo SPIO >〈>EB MISO MOSI RNG TIMER O TEMP TIMER 1 ADC AINO-AIN7 TIMER 2 A QDEC RXD UART XC1 GTS XC2 RIS CLOCK GPIOTE RTCO SDA V|0 RTC1 SDA TWIt Note: RESET Figure 1 nRF51822 block diagram Page 7 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 2.2 2.2.1 nRF51822 QFN48 2.2.1.1 VDD 1 36 AVDD DCC 2 VDD P9.393 34 VSS P.15 N51822 "132 ANT2 926 ANT1 937 QEVVHP ,130 VDD PA YYWWL工 29 DEC2 P.959 128P9.28 P.19 P06711|- 26P9.18 VDD 12 D> 25P8.17 u5OH Figure 2 Pin assignment-nRF51822 QFN48 packet Note: VV= Variant code, hp= build code, yyWwll= tracking code For more information see Section 10.4 on page 52 Page 8 of 67 NORDIC SEMICONDUCTOR nRF51822 Product Specification v1.3 2.2.1.2 Pin functions Pin name Pin function Description VDD Power Power supply DCC Power DC/ DC output voltage to external LC filter P9.39 Digital y/o General purpose I/o pin P.98 General purpose 1/0 pin AREA Analog input ADC Reference voltage P.91 Digital 1/O General purpose l/o pin AlN Analog input ADC input 2 P9.92 Digital VO General purpose l/o pin aln Analog input ADC input 3 P9.93 Digital I/O General purpose 1/0 pin A工N4 Analog input ADC input 4 P.94 Digital I/O General purpose i/o pin AINS Analog input ADC input 5 P2.95 Digital V/O General purpose l/o pin AlN Analog input ADC input 6 P.6 Igital vO General purpose l/o pin AINZ Analog input ADC input 7 AREF1 Analog input ADC Reference voltage P.97 Digital l/o General purpose l/o pin VDD Power Power supply VSS Power Ground (O V) P9.98t 14to22 P.16 Digital I/O eneral purpose l/o pin SWDIO/nRESET Digital V/O System reset(active low). Also HW debug and flash programming I/o 24 SWDCLK Digital input HW debug and flash programming I/o 25to28 P0. 1 to P8.2日 Digital V/O General purpose l/o pin DEC2 Power Power supply decoupling 30 VDD PA Power output Power supply output (+1.6 V)for on-chip RF power amp 31 ANT1 RF Differential antenna connection (tX and rx ANT2 Differential antenna connection (TX and rX 33,34 Power Ground(OV 35,36 AVDD Power Analog Power supply XC1 Analog input Connection for 16/32 MHz crystal or external 16 MHz clock reference 38 <C2 Analog output Connection for 16/32 MHz crystal 39 DEC1 Power Power supply decoupling Page 9 of 67

nRF51822的 ble_app_hrs的说明文档，详细解释了每条语句。

nrf51822空中升级demo