HYPER TERMINAL TEST FOR TROUBLE SHOOTING RS-232(serial port)

Hi friends, are you struck with problems when using serial port during programming micro controllers like getting error message"no response from from micro controller" ???or you have trouble in interfacing computer with external slave processor like micro controller to transfer

data between them.then you are at the right place.

In this tutorial i will give you the way how we troubleshoot the serial port.by troubleshooting you can find out whether your serial port is working properly or not.The method used for this known as "HYPER TERMINAL TEST".

This is how a serial port(DB-9) looks like,shown below:

Pin 2--->data receive

Pin 3--->data transmit

Pin 5---> GND

Step1:

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Short the pins 2 and 3 as shown in the figure.

Step2:

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Now go to start menu in your PC

Start Menu--->All programms--->Accessories--->Communications--->Hyper Terminal

Step3:

-------

When you click hyper terminal,you will get a window as shown in the snap below

enter some name to the connection (i named it "venkatesh") and click 'ok'.

Step4:

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you get a window prompting you to enter location

enter some location and pincode.

select 'connect using' as COM1 and click 'ok'

Step5:

-------

Then you get a window shown below,with small window "com1" settings

select

bits persecond as "9600"

data bits as "8"

parity as "none"

stop bits as "1"

and flow control as "none"

Now click "apply" and "ok"

Step6:

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A blank window appears as shown below with cursor blinking.

keep shorting the pins 2 and 3,type some text with the keyboard

Now , if you can see the text you typed on the window.

then it means that there is no problem with your serial port and every thing is correct with

the PC,if not there is some thing wrong with the PC serial port.

Hence your serial port is TESTED.

Up to this point i have just told you the process to trouble shoot the serial port but didn't tell you

the logic behind what we did actually.

what is the logic behind this hyperterminal test?????

generally

1.whatever input we give from the keyboard,it comes out through the serial port pin 3.

2.and whatever input we get from the serial port pin2,we can display that in hyper terminal

using the above settings.

so keeping this as basis just come back to what we did,we shorted the pins 2 and 3.

by that,what we type in the keyboard is sent to pin3 first and then back to pin2(as they are shorted),so the characters typed by us on the keyboard are displayed back to us:)

Hope you enjoyed the tutorial,for any queries and comments,just post them here or to my mail

have a good day bye:)

--Regards

Venkatesh

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WHAT IS MICROCONTROLLER???

Hi Every one....After My lots of experiments with a little monster called microcontroller, i would like to share my practical experience and knowledge to help you out with,how to use microcontrollers to incorporate intelligence in electronics systems automation.Before going in to the detailed Description of microcontrollers,I just give you a breif introduction.

Basically a microcontroller is a microprocessor with on chip RAM,ROM,I/O ports...etc.

A microcontroller provides intelligence to any system.

suppose that an air conditioning(a.c)  system is that with a microcontroller inside,provides intelligence to it.like sensing the outside temperature,if temperature is high then increase the cooling from a.c and if outside temperature is cool then decrease the cooling of the a.c.

There are several types of microcontrollers used in practice but 3 types are very famous and easy to work with!!

             

we can use any of this type of microcontroller Based on our convinience and requirement.Note that there are many other types of microcontrollers like ARMcortex...etc.but 3 are specifically listed here.
what for this microcontrollers are??
Human uses his intelligence to a accomplish any task.lets take a simple example..suppose the task is to ON or OFF the water pump motor when the tank is empty or full respectively.The same task can be made automated without humans intervention.this is possible if an electronic system can capture the intelligence of human in the form of a program.this is what exactly a microcontroller does.

Microcontroller is a digital device it knows only machine language(low level language) that is zeros and ones(0 s,1s).

and what we know is a a simple 'c' programming language(high level language) in which we can give instructions and Microcontrollers cannot directly understand that.so we have to bridge both the human and microcontroller.so here is how to proceed!!!!!!!!!
                                                                     

so this is overveiw of how to provide intelligence in the microcontrollers with the instructions given by the human.

usully we write a program in our PC and then connect the microcontroller to the computers serial port(com1) or parallelport(lpt1).and then flash the program into the target microcontroller.The program in the form of bits is stored in the EEPROM(flash memory).

a microcontroller can be reprogrammed some 10,000 times.

so the tools required are .................

HARDWARE:

In order to connect the microcontroller with the PC to Flash the program in to the microcontroller we need an interface.

The microcontroller can be programmed in two methods 

1.using serial port of PC(DB-9).

2.using parallel port of PC(DB-25).

SOFTWARE:

1.cross compiler

 eg:KEIL for 8051 and WINAVR for AVR microcontrollers.

2.isp burner program

 eg: isp pgm for 8051 and pony prog for AVR microcontrollers. 

HOW THE CODE is EXECUTED IN MICROCONTROLLER:A cross compiler to covert 'C" code in to HEX code and a ISP BURNER program to convert the HEX code in to BITS(0s and 1s).

eg:    1.  c=b    // assigning value of 'b' to 'c'. in 'c' programming. 

(cross compilr converts a c program toHEX(assembly) so now the instruction is converted              as shown below)

         2.  MOV c,b  //moving value of 'b' to 'c'. in HEX.

                MOV is a mnemonic(user convinience) in HEX it is equivalent to E590h.

               here E5 is a machine code for move in to accumlator from specific memory location and                  90h the address for 'b' together those two bytes make up an instruction.

 (A burner converts a HEX content to BITS(0s and 1s) as shown below)

         3.               E590h

                now writing bit equivalent to the HEX instruction.

                        E------->1110

                        5------->0101

                        9------->1001

                        0------->0000

so the final BIT instruction that a microcontroller can understand is "1110010110010000" is sent to the UART(inside microcontroller) in the serial format by the computer so the bits are then converted parallelly by UART and executed as instruction by CPU of microcontroller.

And thats all for today..hope you liked it.

IN NEXT tutorials we discuss each microcontroller programming and flashing the program in to microcontroller in detail....:)

Feel free to post your comments and doubts, i will be waiting for them!!!!!!!!!

for any help  mail me at electronicsmadeeasy.eme@gmail.com

---->Happy Learning<----

Thank you..:)

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