AT89Sxx Base Board

Tahan Prahara,


This is my second design of the AT89Sxx Base Board. The board is based on the AT89S51, AT89S52, or AT89S53. This board uses STK200 for program loading and includes the serial port at the STK200 header. When I need to program the MCU and need a serial comunication, I do not need to plug and unplug the connector. Because I am using the USB to Serial ISP programmer. Then with the STK200, we must built the parallel programmer STK200. This parallel programmer STK200 can also be use for AVR programmer. This is the reason for the new design.

The complete schematic is shown below.



The PCB layout.

Download the PCB file using Express PCBAT89Sxx.PCB .

How to make PCB? Please visit this link . I recomended to use the 190mg glossy photo paper.

How to use this board.

1.      Make parallel programmer STK200.

2.       Download asm and C-compiler MIDE-51

3.       Before program loading, you can test the code with the TopView Simulator. With this simulator you can learn how to interface the I/O devices, e.g. LED, Keypad, 4x4 keypad, LCD, and serial comunication.

4.       Please visit  for tutorial.

5.       Download Asim's Loader at

If you got questions please contact me at