UART2 is not working on pic18f46k22

ep.hobbyiest · Aug 17, 2017

Hi,
I am using PIC18F46k22 controller with 4 MHz crystal. Compiler is XC8.
I configured UART but it is not working. Not single character is transmitting.

Code:

void initUART(void)
{
    TRISBbits.TRISB6 = 1;
    TRISBbits.TRISB7 = 1;
    
    TXSTA2 = 0x00;
    BAUDCON2 = 0x00;
    SPBRG2 = 25;
    RCSTA2 = 0x90;
    
}

void UartSendChar(char ch)
{
    TXSTA2bits.TXEN = 1;
    TXREG2 = ch;
    while(PIR3bits.TX2IF==0);
    PIR3bits.TX2IF = 0;
}

What i am doing wrong?

paulfjujo · Aug 17, 2017

hello,

What about hardware init ?

ANSELB = 0;
and
PMD0bits.UART2MD=0; // USART2 enable

UART2 with C18

Code:

void Init_UART2_TeleInfo(void)
{
PMD0bits.UART2MD=0;  // USART2 enable    
Delay_mS(10);
// init 1200,E,7,1  10Mhz avec IT en rx
// voir para 18.5 spec sheet DS41159B page 186
Open2USART( USART_TX_INT_OFF &
USART_RX_INT_ON &       //interrupt  possible
USART_ASYNCH_MODE &
USART_CONT_RX &
//USART_SINGLE_RX &
USART_EIGHT_BIT &        // use of 7 bits 8em bit =Parite
USART_BRGH_LOW,208);  // 16Mhz FOSC interne sans PLL  ... OK 
// .. OK avec surcharge ci dessous ...voir dtasheet page 283 
//TXSTA2bits.BRGH=0;  //at 40MHz
TXSTA2bits.BRGH=1;  // at 20Mhz
BAUDCON2bits.BRG16=1;
//SPBRGH2=0x08; //2083 pour Q=10Mhz x 4 (PLL) => 40Mhz avec BRGH=0;
//SPBRG2=0x23;
SPBRGH2=0x10; //4160 pour Q=20Mhz avec BRGH=1;
SPBRG2=0x40;
//SPBRGH2=0x1A; //6656  pour FOSC=8x4=32Mhz avec BRGH=0;
//SPBRG2=0x00;
//SPBRGH2=0x0D; //3332  pour FOSC=16x4=64Mhz avec BRGH=0;
//SPBRG2=0x04;
}  

void Init_UART2_19200(void)
{
    
PMD0bits.UART2MD=0;  // USART2 enable    
Open2USART( USART_TX_INT_OFF &
USART_RX_INT_ON &       //interrupt  possible
USART_ASYNCH_MODE &
USART_CONT_RX &
USART_EIGHT_BIT &        
USART_BRGH_HIGH,65);   // @ 20Mhz  19200bds  // 16Mhz FOSC interne sans PLL  ... OK 

}

spudboy488 · Aug 18, 2017

Try this. Do your own BAUD calculation.

This should work for UART1 on a 44pin TQFP. Change ANSEL and TRIS bits if your UART comes out on different pins

Code:

void Init_RS232(void) {

	// RS232 Initialization

        ANSELCbits.ANSC6=0;                                                                     // Disable AN18
        ANSELCbits.ANSC7=0;                                                                     // Disable AN19
        TRISCbits.RC6=0;                                                                        // Set TX as output
        TRISCbits.RC7=1;                                                                        // Set RX as input

	RCSTA1bits.SPEN=0;									// Disable serial port to make changes	
	TXSTA1bits.SYNC=0;									// Asynchronous
	TXSTA1bits.BRGH=1;									// Enable 16 bit baud rate gen.
	SPBRG1=BAUD;										// 115,200

	TXSTA1bits.TXEN=1;									// Enable TX
	RCSTA1bits.CREN=1;									// Enable RX
	RCSTA1bits.SPEN=1;									// Enable Serial port
	PIE1bits.RC1IE=1;									// Interupt on RX
	
	INTCONbits.PEIE=1;									// Enable peripheral interrupts
	INTCONbits.GIE=1;									// Enable global interupts
}

void Send_RS232(unsigned char Tx_data) {

	TXREG1=Tx_data;										// Send it
        while (!TXSTA1bits.TRMT);							        // Wait for character to finish
}

baileychic · Aug 18, 2017

Id PIDP package then UART2 is on PORTD. Set TRISD bits accordingly and also clear ANSELD.

paulfjujo · Aug 18, 2017

Hello,

This one function ( UART1) is working.. tested in real condition
OK at 4MHz and (also tested at 16 Mhz)
BRG16 must be set ..
and also
added UART2 !

Subroutines

Code:

  void Init_UART1(void) 
  {
        ANSELC.ANSC6=0;   // Disable AN18
        ANSELC.ANSC7=0;   // Disable AN19
        TRISC.RC6=0;      // Set TX as output
        TRISC.RC7=1;      // Set RX as input


    RCSTA1.SPEN=0;    // Disable serial port to make changes
    TXSTA1.SYNC=0;    // Asynchronous


    // test at 16MHz 19200  .. OK
    //TXSTA1.BRGH=1; // Enable 16 bit baud rate gen.
    //BAUDCON1.BRG16=1;
    //SPBRG1=208;    // 19200 at 16Mhz   error -0.32%


         TXSTA1.BRGH=1;    // at 4Mhz
         BAUDCON1.BRG16=1;
         SPBRG1=52;     //19200 bauds eror 1,73%


    TXSTA1.TXEN=1;    // Enable TX
    RCSTA1.CREN=1;    // Enable RX
    RCSTA1.SPEN=1;    // Enable Serial port
    
   // Interrupt  not yet enable
    PIE1.RC1IE=1;
    INTCON.PEIE=0;
    INTCON.GIE=0;
}


void Send_UART1(unsigned char Tx_data)
{
        while (TXSTA1.TRMT==0);
    TXREG1=Tx_data;
}


void UART1_Print_CText(const char *txt)
 { char cx;
   cx=*(txt);
   while (cx>0)
   {  cx=*(txt++);
      Send_UART1(cx);
      }
}


  void Init_UART2(void) 
  {
        ANSELB=0;   // NO analog on port B
        TRISB.B6=0;      // Set TX as output
        TRISB.B7=1;      // Set RX as input
        PMD0.UART2MD=0;  // USART2 enable
    RCSTA2.SPEN=0;    // Disable serial port to make changes
    TXSTA2.SYNC=0;    // Asynchronous


    // test at 16MHz 19200  .. OK
    //TXSTA1.BRGH=1; // Enable 16 bit baud rate gen.
    //BAUDCON1.BRG16=1;
    //SPBRG1=208;    // 19200 at 16Mhz   error -0.32%


         TXSTA2.BRGH=1;
         BAUDCON2.BRG16=1;
         SPBRG2=52;     //19200 bauds eror 1,73%


    TXSTA2.TXEN=1;    // Enable TX
    RCSTA2.CREN=1;    // Enable RX
    RCSTA2.SPEN=1;    // Enable Serial port
 // RX Interrupt  not yet enable
        PIE1.RC2IE=0;
    INTCON.PEIE=0;    // disable peripheral interrupts
    INTCON.GIE=0;    // disable global interupts
}


void Send_UART2(unsigned char Tx_data)
{
        while (TXSTA2.TRMT==0);
    TXREG2=Tx_data;
}


void UART2_Print_CText(const char *txt)
 { char cx;
   cx=*(txt);
   while (cx>0)
   {  cx=*(txt++);
      Send_UART2(cx);
      }
}

code for testing ...

Code:

void main() 
{


 #ifdef OSCILLATEUR_INTERNE
 // 1MHz par defaut car OSCON RAZ au reset
    OSCCON=0;
 // OSCCON=0b01110000;
 // OSCCONbits.IRCF2=1; //HFINTOSC - (16 MHz)
 // OSCCONbits.IRCF1=1;
 // OSCCONbits.IRCF0=1;
   OSCCON.IRCF2=1; //HFINTOSC - (4 MHz)
   OSCCON.IRCF1=0;
   OSCCON.IRCF0=1;
  // SCS<1:0> System Clock Select bit
  // 1x = Internal oscillator block
  // 01 = Secondary (SOSC) oscillator
  // 00 = Primary clock (determined by FOSC<3:0> in CONFIG1H).
  OSCCON.SCS1=1;
  OSCCON.SCS0=0;
  OSCTUNE=0;
  OSCTUNE.PLLEN=0;  // 1= avec PLL => 64Mhz ou 40Mhz   0 =sans PLL => 16Mhz  ou 10Mhz
  #else
  // FOSC=Q=20MHz
 #endif
 




  Init_UART1();
  Delay_ms(10);
  Send_UART1(10);Send_UART1(13); // CRLF
  UART1_Print_CText("Debut de test UART1 RC6=TX RC7=RX  19200,8,N,1  Fosc=4 Mhz\r\n");
  Send_UART1(65);Send_UART1(66);Send_UART1(67);  // send ABC
  Send_UART1(10);Send_UART1(13); // CRLF
  for (i=65;i<128;i++)
  {
   Send_UART1((unsigned char)i);
   }
   Send_UART1(10);Send_UART1(13);
   UART1_Print_CText("Fin test UART1 \r\n");
   Send_UART1(10);Send_UART1(13);
   
   UART1_Print_CText("Debut de test UART2 ..\r\n");


    Init_UART2();
    Delay_ms(10);
  Send_UART2(10);Send_UART2(13);
  UART2_Print_CText("Debut de test  UART2 RB6=TX  RB7=RX  19200,8,N,1  Fosc=4 Mhz\r\n");
  Send_UART2(65);Send_UART2(66);Send_UART2(67);
  Send_UART2(10);Send_UART2(13); // CRLF
  for (i=65;i<128;i++)
  {
   Send_UART2((unsigned char)i);
   }
   Send_UART2(10);Send_UART2(13);
   UART2_Print_CText("Fin test UART2 \r\n");
   Send_UART2(10);Send_UART2(13);
   
    while(1);
    
}

display result for UART1 test

Debut de test RS232 19200,8,N,1 Fosc=4 Mhz
ABC
ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
Fin test RS232

UART2 test

Debut de test UART2 RB6=TX RB7=RX 19200,8,N,1 Fosc=4 Mhz
ABC
ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
Fin test UART2

paulfjujo · Aug 18, 2017

sorry,i didn't pay attention for theMCU type,
my example is for 18F26K22 .. without port D
just adapt input and output UART2

Code:

ANSELD=0;   // NO analog on port B
TRISD.B6=0;      // Set TX as output (TX2  EUSART asynchronous transmit data output)
TRISD.B7=1;      // Set RX as input  (RX2  EUSART asynchronous receive data in.)

ep.hobbyiest · Aug 18, 2017

I tried example gave by you and its working.
I change the port setting and change the confi and its start working.

Code:

    ANSELD = 0x00;
    TRISDbits.TRISD6 = 1;
    TRISDbits.TRISD7 = 1;

UART2 is not working on pic18f46k22

ep.hobbyiest

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paulfjujo

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spudboy488

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baileychic

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UART2 is not working on pic18f46k22

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