PIC24H Uart send only 4 bits correct - need to split

Question

I am working with the explorer16/32 evb and trying to send data to UART. I tried UART1, UART2 with and without interrupts and got the same problem all the time.
It appeared that in order to send 1 byte I need to split it to two 4 bits with shift

code:

#define FCY 16000000 
#define BAUDRATE 9600
#define BRGVAL ((FCY/BAUDRATE)/16)-1
U2MODE = 0;
U2STA = 0;
U2MODEbits.STSEL = 0;   // 1-Stop bit
U2MODEbits.PDSEL = 0    ;   // No Parity 8 bit data
U2MODEbits.ABAUD = 0;   // Auto-Baud Disabled
U2MODEbits.BRGH  = 1;   // High Speed Mode
U2MODEbits.URXINV = 0;    
U2STAbits.UTXINV = 0;    
U2BRG = BRGVAL;         // Baud Rate Setting for 9600

U2MODEbits.UARTEN = 1;   //Enable UART module
U2STAbits.UTXEN = 1;    //Enable UART TX 


unsigned char putU2(unsigned char c) 
{       

   while (U2STAbits.TRMT == 0)
   {

   }    
   while ( CTS);                
   while ( U2STAbits.UTXBF);    
   U2TXREG = c & 0xF;
   U2TXREG = (c >> 4) & 0xF;
   return c;
}

If I am sedning that data splited to 4 bits I can see the data correct on the PC( c# serial port application) But it should not be split into two writes to U2TXREG.

I am not 100% sure that the FCY is 16000000 but this is the only value that give me reasonable result.

What could be the problem?

Answer 1

For PIC24H, in UART high speed mode ( BRGH = 1 ) to get correct value of BRGVAL you need to divide by 4, not 16. Change the formula on line 3. Also, it is helpful to be 100% sure about clock rate; if you didn't change configuration bits it is likely 8 MHz, not 16.