Feature: 1. 5V, 3V compatible design, suitable for 5V and 3V chip work, commonly used AVR microcontrollers can be used to meet the needs of different users. 2. The development board has 8 SMD LED lights, 6 SMD buttons, 4 LED digital tubes. 3. The buzzer has sound prompts, and can be used for music, alarm, etc. experiments. 4. Serial port conversion chip MAX3232, which supports both 5V and 3.3V voltage, can realize serial communication, single‑chip programming and other functions. 5. The temperature sensor interface and infrared receiving interface can be used for infrared receiving experiments such as H1838, which can realize infrared remote control keyboard expansion. 6. The ISP interface is the interface for AT/AVR microcontroller to download programs, and can be equipped with a corresponding USB-ISP downloader. 7. Mini USB power supply and external stabilized power supply, onboard 3.3V stabilized power supply chip. 8. 5V and 3.3V power selection switch, expand the scope of use, and on‑board devices can work normally within 5V and 3.3V. 9. Out all IO ports for easy operation and expansion of external devices, 3.3V and 5V power supply expansion interface, can provide power for external devices. Specification: Item Type: Development Board Material: Synthetic cardboard Purpose: The 51 single-chip development board is an experimental learning device for learning 51, and AVR models of single-chip computers Input Voltage: 3-5V Transmission Method: Serial port download and isp download are applicable Package List: 1 x Development Board1 x USB Data Cable