[Hangshun Training Camp] NFC Card Reader +215646S

• NFC card reader. Card reading data is stored in the cloud and called by PC.
• Main hardware specifications:
• Main control chip: HK32F103. The price of STM32F103 is currently rising. Therefore, the plan is to switch to domestic IC, which happens to be promoted by HK and Lichuang. So I went on board to do the test.
• NFC reading and writing chip: MFRC52202HN1. NXP. The price is also too expensive to accept. Lichuang single chip is available at 30RMB. The plan is also to switch to domestic brands. The current price on Taobao is pretty good. So I’ll just use it for this test for the time being.
• WIFI.BT module ESP32-S. It was originally planned that ESP-32 would directly drive NFC and save the main control. But I just happened to do some chip testing, so I used the HK controller.
• OLED module: 12864 module, 7-pin SPI communication. There are also 4-pin I2C ones. Everyone likes this. Freedom of choice. I planned to try dual SPI, so I used a 7-pin one. I2C is reserved for others
• Storing EEPROM: Haha. I originally chose HK's 24C64, but it was out of stock. Domestic supply capacity needs to be improved. Even the HK32F103 controller is out of stock at Lichuang. I bought it at Wanbao. Not sure how the HK chip's EEPROM and flash read and write. So leave an EEPROM to store it. If the main control EEPROM is OK, this can be saved.

1.  NFC reads and writes cards.
2. Read data and transfer to PC via USB 
3. The read data is transferred to PC via WIFI or uploaded to the cloud. The board has arrived.

I haven't had time to write a program yet. Do it again when you have time. It took the whole morning to put the board up. I originally wanted to study SMT at Lichuang. But the 20 yuan coupon is a bit small. Ha ha.

So I can only paste it by hand. After posting it, I found that there was no washing water, haha, the dirty ones are all in the picture. I have tested the battery and it has no problem charging. The power supply voltage is fine. The next step is to write software.

After writing the software for a day, the display can light up.

After another two days, I was really tired from doing the project. Ha ha. NFC network matching debugging, RC522 software debugging. Finally got the NFC function done.

The network matching of NFC radio frequency has been done for a long time, but there are many pitfalls. The 2.2uH inductor bought by Lichuang, ±10%. The actual measured value is 4.6uH. +200% deviation. Hey, I don’t want to say it. The unscrupulous manufacturer wasted my day. It’s up to you to figure out which brand it is. If the manufacturer has any opinions, you can contact me to discuss. Is there something wrong with my digital bridge? In the end, I adjusted the circuit according to my broken instrument.

The PCB coil is very small, and the receiving distance is about 1.5CM. It is not very strong.

The NFC drive circuit parameters have been adjusted, and the schematic diagram has not been updated yet. I will update it when I have time. The reference of different circuit boards will be different. If you use this circuit, you still have to adjust the network matching yourself. This is not just copying. How to adjust can refer to NXP official documentation. You can also comment and communicate.