89SXX ISP PROGRAMMER USING SERIAL PORT(COM1)

Generally parallel port method is preferred as it is very easy,but

what if we don't have a parallel port for our computer??
so the alternative is serial port programmer.
serial port programmer method uses serial port(DB-9)(com1).
This programmer is a bit complex circuit to construct compared to parallel port method.

89sxx serial programmer circuit:

click on image to enlarge

Download schematic in pdf file

Download hex file

Download ISP PROG software

SOFTWARE TOOLS:

After the circuit is connected as shown in the above schematic,we should use
a software to fuse bits in to the EEPROM of microcontroller,the software i used
here is "ISP_PROG v1.4".install this software and u can see this window.

step1:
------
Now go to options menu and select
settings option,you will get a window asking you to set the com.
as we are using serial port,we select the option com1.and click "ok".

step2:
------

again go to options menu you can see select device option click it,you get
a select device window.select the device as 89s52,as we are using this micro
controller here.and then click "ok".
step3:

------

now select "write device" option and click "RUN" you can now see the status
of the burning of the device.
when the burning process is finished,you get the "finish" message.
now your device is programmed successfully!!!!
so enjoy!!!!:)


EXTRA READING:
---------------------
1.in this method the microcontroller cannot directly communicate with the serial
port of computer it communicates via another slave micro controller.
2.the slave micro controller used between the target microcontroller is pre-programmed
with a boot loader program,this program facilitates programming the micro via serial port.

more on boot loader here.
3.you can see in the figure the first microcontroller is connected to the serial
port of computer through MAX232.the serial port voltage
levels are incompatible with microcontroller voltage levels(TTL).
more about level conversion in my previous tutorial IC MAX232 FOR INTERFACING RS232

so this ic level converts between the serial port and the microcontroller.

4.The 89c2051 again uses a parallelport method to burn code in to it.
5.here the capacitors used around the MAX232 ic are used for clamping the
voltage levels.
6.if your computer dont even have this serial port(laptops dont have serialports),
no problem as every computer now a days have a USB connection,you can use a USB
to SERIAL PORT converter.
7.before using the USB to serial port converter,dont forget to install
USB to serial port drivers.otherwise the device wont be detected at all.
8.if the programmer doesnt work dont panic,there is an easy way of troubleshooting
the serial port,which is discussed in troubleshooting the serialport tutorial.
*****any queries or comments ??? just post them here,or mail me,Thank you!!!!!!!!**********
-Regards
venkatesh