I have included two circuits here:-
  1. 89SXX ISP Programmer using RS232 Interface.
  2. 89SXX ISP Programmer using USB interfacing.
            Fig. 1 shows the Schematic of Programmer with RS232 interface.
The above circuit uses RS232 for interfacing with PC. It is very simple circuit & works very well with PC.Power is drawn from usb port OR needs external supply of 5V.
The value of the crystal is very critical at AT89C2051 and must be 11.0592MHz .Here AT89C2051 is loaded with firmware required for RS232 communication with PC. Assemble the circuit and burn the firmware into an AT89C2051 (you will need a conventional parallel Programmer to Program the AT89C2051).Use the 40 pin ZIF socket for microcontroller.The firmware(.HEX) file is in the Software folder. All the required documents and Files are attatched.

1)     Don’t panic if computer is not able to detect kit Please check all the connections on the board. While designing circuit manage to make jumper-less circuit.
2)       Before connecting it to PC check if any paths are shorted to another.
3)       Verify if the firmware is burned appropriately or not.
4)      Check voltage level at the two pins of the crystals it should be approx. 0.7 - 0.27V.     When you run the software for the first time it looks for a valid programmer on COM1. If the Programmer is connected to say COM2 you will receive an error message but when the application starts select Options->Settings on the Menu and specify the correct COM Port.
6)      Check RS232 cable. Check continuity of every pin.

Fig. 2 shows the Schematic of Programmer with USB interface.

In this circuit power is drawn from usb port itself, so no need of external power supply. Led at the bottom is connected to p2.7 for testing purpose.you can write program to turn on & off the led.led is connected in sinking mode.FT232 is an SMD , its on the bottom side of the board so you can see only 2 ICs in the above circuit.

1)      Once you are done with USB circuit.Connect the circuit to Computer.
2)      Download Virtual COM Port (VCP) drivers for FT232RL from http://www.ftdichip.com/
3)      For installation Guide of VCP Drivers open “VCP Drivers installation Guide.pdf”
4)      After Device Drivers Installation go to
Control Panel\Hardware and Sound\Device Drivers\

After this step open ISP Programmer and configure the COM#  port in “Option>Settings>”

Component List for usb programmer

 Note:Purchase 8051 of S series only (89's'XX)-40pins DIP 

If you are purchasing components from Mumbai(Lamington Road.) you can program 89C2051 (firmware IC) from VishaKits near GALA.

I have attached PCB layout (for USB only) & related softwares.

Click Here to download files. 

(Links Updated on Dec.26 2011)