[SOLVED] Send data from Matlab to 8051 using proteus simulation.

[kishore680]

Hi i have written small matlab code

s = serial('COM4','BaudRate',9600);
 fopen(s);
 fprintf(s,'A');

My circuit in proteus .. IF i send higood. i got this as output in virtual terminal . And the keil code for receiving data serially is

#include<reg51.h>
void sertex(unsigned char);
void main(void)
   {							  unsigned char z;
						   TMOD=0x20;
						   TH1=0xFD;
						   SCON=0x50;
						   TR1=1;
				 		  
						   
			while(1)
{

while(RI==0);
z=SBUF;
P1=z;
RI=0;


}
}

. Please someone tell me whats the fault in circuit or in programme.I need to send data from PC and make sure microcontroller received it properly.Thanku

 

[jayanth.devarayanadurga]

You have connected Rx pin and Tx pin of MCU to RxD and TxD pins of Virtual Terminal. It is wrong. You have to cross the wires. Rx to TxD and Tx to RxD.

 

[kishore680]

HI tried that.In that case no data is displayed in the virtual terminal!!! Its blank... IF i take connection from COMPIM to virtual terminal i am getting exact result in virtual terminal

 

[jayanth.devarayanadurga]

Where is your UART initialization settings? i.e., TMOD, EA, etc...

Ok. I see it is there. 9600 bps is your baudrate.

There is no serial transmit code. It receives serial data and assigns it to some port. How can you expect data in Virtual Terminal?

Just connect Rx pin of MCU to TxD pin of VT and remove the other connection from Tx of MCU and also RTS to CTS in VT.

 

[kishore680]

TMOD=0x20;
TH1=0xFD;
SCON=0x50;.. Baud rate s 9600 everywhere!!.IS the max232 connection proper?

- - - Updated - - -

Ohk i thought i can tap that serial output and display . MY bad!! .So sir, what changes i have to make to appear data in the virtual terminal ?

 

[jayanth.devarayanadurga]

---

Code C - [expand]
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void Tx_Char(unsigned char Data)
{
    SBUF=Data;              //SEND CHARACTER TO SERIAL BUFFER
    while(!TI);             //WAIT HERE TILL THE TRANSMIT INTERRUPT FLAG GOES TO                        //HIGH
    TI=0;                   //CLEAR TRANSMIT INTERRUPT FLAG
}
 
unsigned char Rx_Char()
{
    while(!RI);             //WAITING FOR CHARACTER
    RI=0;                   //CLEAR RECEIVE INTERRUPT FLAG
    return SBUF;                //RETURN DATA
}

---

Try receiving data in mcu and transmitting it again to VT. Have you selected COM4 in VT?

 

[kishore680]

I have selected COM2 in COMPIM,,COM2 and com4 are in pair.I have done that using virtual serial emulator IN virtual terminal i have just set baud rate to 9600 .Didnt see any option for com port.

 

[jayanth.devarayanadurga]

Select COM4 in COMPIN or change in matlab to COM2.

 

[kishore680]

#include<reg51.h>
void Tx_Char(unsigned char);
void main(void)
   {							  unsigned char z;
   
   
						   TMOD=0x20;
						   TH1=0xFD;
						   SCON=0x50;
						   TR1=1;
						  
						   
						  
						   
			while(1)
{

	while(RI==0)
	z=SBUF;
	Tx_Char(z);
	RI=0;

}
}
	void Tx_Char(unsigned char c)
	{SBUF=c;
	while(TI==0);
	TI=0;
	}

This i modified and tried,YEt VT is blank.

 

[jayanth.devarayanadurga]

remove cts to rts connection in com pin. if that doesn't work then connect VT before MAX232 i.e., between MAX232 and COMPIN.

 

[kishore680]

IF i connect COMPIM to virtual terminal.I m getting exact result.But how do i knw microcontroller has received exact data?

 

[jayanth.devarayanadurga]

Receive data in MCU and resend it. It will appear in VT. Just connect Tx pin of MCU to RxD pin of VT. Don't connect any other connections for RTS, CTS and Rx of MCU to TxD of VT.

 

[kishore680]

Code is the modified one. But didnt get..I tried sending from 8051 to VT. I got output!

 

[jayanth.devarayanadurga]

You can place multiple VTs in Proteus. Put one between COMPIN and MAX232 and another between MAX232 and MCU.

 

[kishore680]

No thats not coming the one between max232 and MCU!

 

[jayanth.devarayanadurga]

Post your project files and also proteus file. Zip it before posting.

 

[kishore680]

Thank you. i have attached!Hex file is in keil folder. you have to load that into 8051

 

[jayanth.devarayanadurga]

See this image.

I finally found the problem and its solution. See image 2. The data out of the MAX232 is inverted. In VT between COMPIN and MAX232 select invert.

 

[kishore680]

Thank you very much for finding the problem.. sir can u attach that proteus file?. And what about code.Did u modify

 

[jayanth.devarayanadurga]

See attached file. I didn't change any code. The MAX232 output will be inverted.