The main function:
1. RS485 communication theoretical communication distance 1200 meters
2. RS232 communication (green DB9 interface)
3. EEPROM (24C16)
4. Red 3 LED lights
5. Press 3
6. Buzzer one
7. Digital tube 4-in-one SEGLED (74HC595 drive, 3-wire system)
8. The remaining IO ports are brought out
9.TF card (SPI interface)
Chip Control: The purpose is to let PC programmers learn the programming methods of controlling hardware and have a preliminary understanding of digital circuits.
1. RS485 understands the implementation of half-duplex telematics.
2. LEDSEG (seven-segment digital tube) uses two 74HC595 chips. Serial (connected to the Raspberry Pi 3 lines) to parallel mode (connected digital tube) control.
3. TF card data storage (large-capacity data): To understand the storage of large-capacity data, you usually need to write your own file system or transplant a third-party file system (such as FATFS microcontroller)
4. Onboard LED circuit (directly connected to Raspberry Pi): Learn to use the Raspberry Pi GPIO port to easily realize the control of LED hardware. Learn the operation of the Raspberry Pi GPIO port output control.
5.KEY button circuit: Learn to use the Raspberry Pi GPIO port to easily realize the recognition (read) of the button. Learn the operation of the Raspberry Pi GPIO port input control.
6. EEPROM (small capacity data) data storage, generally store some configuration parameters, version number and other information: learn to use the hardware storage operations. At the same time, familiar with hardware IIC.
7. BUZZER, the control principle is the same as the control LED light.