Description: The minimum system board using STC and AVR dual reset operation, more user-friendly debugging of the program; 1.5V and 3.3V power supply options to expand the use of single-chip, this is the company's first design, customers no longer have to use low-voltage microcontroller and worry! On-board expansion of the STC microcontroller program download interface, and the store sell STC downloader with the use of excellent results. AT89S51 / 52 and AVR series MCU can be downloaded through the ISP dedicated downloader program. Double panel, value low-cost sales. Specification: Customers in the proficiency of 51 single-chip, further learning AVR microcontroller, only through an AVR microcontroller adapter board, You can continue to use the small board as the AVR microcontroller minimum system; PCB double-sided grid CC design, green and blue two colors, and some monolithic board on the market is not a level; MCU 40 I / O pins all lead. Part of the components using a built-in and patch packaging design, simple structure tight, strong sense of technical art; Crystal: 11.0592M Support chip: STC series of low-voltage high-voltage chip AT89SXX and chip pin compatible with the chip , AVR microcontroller DIP-40 pin package. The minimum system board, whether 51 or AVR series microcontrollers are double reset mode of operation. Can be powered by USB, with 5V power supply mode, can save a 5-10 yuan power supply; also DuPont line external power supply, power supply options! With two 5V and 3.3V VCC, GND output, to facilitate the use of external circuits; With reverse voltage breakdown components to prevent the protection of the diode, greatly improving the safety of the system board. Download with CP2102 and other serial modules supporting the use of Size Chart: Size: Approx. 28*10*8mm / 1.10x0.39x0.31inch Package Includes:(4 Pack) 1 Piece of Development Board