Project Board for AT89S52

Overview

The 89S52 project board was designed for easy microcontroller development as it contains an In-System Programmable Flash based microcontroller.

Explanation

Among the components used in this project include the ISP loader, four tact switches, text LCD connector, 4-digit 7-segment LED, 5V regulator, 16-pin I/O port connector, and two-channel 12-bit ADC. The AT89S52 is an 8kB flash microcontroller.

Also illustrated by this project is the use of an analog AC clamp meter with the active power in Watt unit being displayed by the 89S52 project board. The input of the 12-bit ADC contained in the board is 0 to +5VDC. An output current of 100uA per 30A is provided by the AC clamp meter. By multiplying the RMS voltage to the RMS current, the program can simply compute the active power. The short circuit input for the current source is provided by the current-voltage converter using LM324. The 100Hz ripple from AC clamp meter is filtered by adding C1.

Using 6-pin ISP socket and DB25 connector, the ISP loader can be built with less than 50cm wire length. This loader can also be used for programming the 89S52 since the hardware is compatible with ISP software.