PIC16f1527 UART baudrate formula

[ragav4456]

Hi friends

I doubt in PIC uart baudrate formula calculation in Program.

BRGH=1;BRG16=1; kindly send the sample code.

Sample code for PIC16f877A ic UART

int X;
	
	/* calculate and set baud rate register */ 
	/* for asynchronous mode */
	tmp = 16UL * baud;
	X = (int)(FOSC/tmp) - 1;
	if((X>255) || (X<0))
	{
		tmp = 64UL * baud;
		X = (int)(FOSC/tmp) - 1;
		if((X>255) || (X<0))
		{
			return 1;	/* panic - baud rate unobtainable */
		}
		else
			BRGH=0;	/* low baud rate */
        }

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how to change this code for pic16f1527 ic?

 

[jayanth.devarayanadurga]

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Code C - [expand]
1
X = (FOSC/(16UL * baud)) - 1

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[ragav4456]

Baudrate formula depends upon this bits BRGH=1; BRG16=1;


BRG16 meaning?

 

[jayanth.devarayanadurga]

See the images.

 

[ragav4456]

I have doubt in 57600 is 16 bit baudrate or 8 bit baudrate.?

 

[jayanth.devarayanadurga]

See this table. What is your Fosc?

For Fosc = 20 MHz, SYNC = 0, BRGH = 1, BRG16 = 1, and baudrate 57600 bps, SPBRG value = 86. So, it is 0086. SPBRGH = 00, SPBRGL = 86.

 

[ragav4456]

FOSC-20MHZ Baud rate-57600

 

[jayanth.devarayanadurga]

See my last post.

 

[ragav4456]

SPBRG= 86; means UART not working. what is the reason?
the first post is automatic calculation of SPBRG=X.

UART output is varied. My program starting bit is 35, but output is 82 or 80 and some other else.

 

[jayanth.devarayanadurga]

Are you testing on Hardware or Proteus? If on Hardware maybe your PIC UART is damaged.

 

[ragav4456]

I am testing in HARDWARE.

 

[jayanth.devarayanadurga]

Test in Proteus. if it works then the problem is in your PIC. Post your circuit, hex and cof files and I will test in Proteus.

 

[hemporer]

just change associate register.

 

[ragav4456]

associate register means?

 

[jayanth.devarayanadurga]

Use UART2 instead of UART1.