摘要:目前，單片機廣泛應用于各個領域，隨著各種單片機類型地發展，單片機的功能也在逐漸完善，其中AT89S51單片機可實現ISP在線編程功能，即可直接在目標系統或電路板上燒錄程序，并且可以反復燒錄，無需購置專用編程器等優點。利用這一特點可以大大減少在實時檢測和自動控制的單片機應用系統中的工作量，再根據它的具體結構，然后再對具體應用對象特點的軟件結合來進行開發設計。

　　　本文首先對單片機的研究意義和研究現狀進行了分析，還對單片機特別是AT89S51單片機的結構特點和重要引腳功能進行了介紹，同時對AT89S51單片機在線編程器進行了詳細的設計及分析，最后進行了各個電路的程序設計及調試，以保障設計的單片機各個功能能夠正常運行。

關鍵詞： AT89S51單片機　ISP　設計及調試

ABSTRACT:At present, SCM is widely used in various fields, along with a variety of microcontroller type development, the function of MCU are also gradually improved, AT89S51 to achieve ISP online programming function, can be burned directly in the target system or circuit board, and can be repeated burning, the advantages of no purchase special programmer etc.. Use this feature can be greatly reduced in the MCU application system for real-time detection and automatic control of the workload, then according to its specific structure, and then the specific characteristics of the target application software to design.

　　　Firstly, the research significance and the research status of SCM is analyzed, and puts forward some improvement methods. Based on SCM especially the structure characteristics of AT89S51 single chip and pin function is introduced, and a detailed analysis of the design of AT89S51 single chip microcomputer online programmer, the end of the program design and debugging of the circuit, in order to ensure the design of each single machine function to the normal operation of. 

Keywords：AT89S51 microcontroller；ISP；designing and debugging