CODEWITHSUNDEEP
microcontrollerpicuartmicrochip
Gorgi Vladimirov
Gorgi Vladimirov

Reputation: 1

UART communication PIC16f877A

I've been working on a project which requires communication with my laptop and the microchip Pic 16f877a and the communication is not working properly, but When i put this example on Proteus 8 works just fine.
I don't have RS232(serial port) on my laptop, but i had bought TTL module. I use external oscillator 8MHz on the board and baud rate of 9600 bps.

When i connect with my laptop and i send to the TTL module the A symbol nothing hapens and when i send a couple of times A fast i recieve strange symbol like '?' or '#' back.

Here's the code for the Pic:

char x;
void main(){
  TRISB = 0x00;
  PORTB = 0x00;
  UART1_Init(9600);
  delay_ms(10);
while(1){
  if(UART1_Data_Ready())
  {
     x = UART1_Read();
     if(x == 'A')
     {
         PORTB = 0xFF;
         UART1_Write(13);
         UART1_Write_Text("A");
         UART1_Write(13);
     }
     else
     {
        PORTB = 0x00;
     }
  }
 x= '\0';
}
}

Can someone help me ? What's the problem ?

Upvotes: 0

Views: 1688

Answers (2)

honeybee1881
honeybee1881

Reputation: 44

give 

SPBRG = 139

Refer this link to set the respective Baud Rate Generator

Upvotes: 0

DiBosco
DiBosco

Reputation: 876

Two possibilities as far as I can see (assuming UART1_Init(9600); is a correct library function):

  1. You don't have the Rx pin set up as an input; setting TRIS registers to 0 makes all the pins on that port outputs.

  2. You are using incorrect parity.

Have you set a breakpoint at line 

x = UART1_Read();

To see what you actually get in when you send from your terminal program?

Have you looked on youe scope to see what is actually coming in on the Rx pin?

delay_ms(10); is completely unnecessary.

Upvotes: 0

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