一、前言
Arduino Nano 结合 RFID-RC522 实现M1卡读写。
二、接线
越是基础越是别出错，有时候出问题半天解决不了，最后发现线接错了。所以新手请注意。接线如下图
接线示意图（图片来自网络）
![图片来自网络]
没有OLED的不必理会
根据不同颜色的杜邦线方便区分
| RFID-RC522 | Nano | Color |
|---|---|---|
| 3.3V | 3.3V | RED |
| RST | PIN9 | YELLOW |
| GND | GND | ORANGE |
| RQ | ||
| MISO | PIN12 | BROWN |
| MOSI | PIN11 | BLACK |
| SCK | PIN13 | WHITE |
| SDA | PIN10 | GRAY |
三、代码
在编写代码之前我们需要添加 RC522 对应的库。https://www.arduinolibraries.info/libraries/mfrc522
下载你喜欢的版本（我一般下最新版）
然后打开 Arduino >> Sketch >> Include Library >> Add .ZIP library..
选择刚刚下载的库文件如 MFRC522-1.4.4.zip 进行类库的添加，类库添加成功之后我们可以看看第三方提供的 Example ， Arduino >> File >> Example >> MFRC522
然后选择其中一个案例如 ReadAndWrite
ps: 发现文档中已有接线说明
* Typical pin layout used:
* -----------------------------------------------------------------------------------------
* MFRC522 Arduino Arduino Arduino Arduino Arduino
* Reader/PCD Uno/101 Mega Nano v3 Leonardo/Micro Pro Micro
* Signal Pin Pin Pin Pin Pin Pin
* -----------------------------------------------------------------------------------------
* RST/Reset RST 9 5 D9 RESET/ICSP-5 RST
* SPI SS SDA(SS) 10 53 D10 10 10
* SPI MOSI MOSI 11 / ICSP-4 51 D11 ICSP-4 16
* SPI MISO MISO 12 / ICSP-1 50 D12 ICSP-1 14
* SPI SCK SCK 13 / ICSP-3 52 D13 ICSP-3 15
四、上载程序
打开Arduino IDE >> TOOLS 下选择对应的 board 以及 port
点击上载程序按钮，这里需要注意的是，如果一直无法上传成功的话。报以下错误
Sketch uses 8566 bytes (27%) of program storage space. Maximum is 30720 bytes.
Global variables use 307 bytes (14%) of dynamic memory, leaving 1741 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00
An error occurred while uploading the sketch
尝试将 Processor 这里切换为 ATmega328P(Old Bootloader)
需要注意的是 程序默认使用的 Key A 为 FFFFFFFFFFFF 所以请确认你的卡片Key A 与其对应