Serial Port Complete - Latest Microcontroller projects

Ports for Embedded Systems

If the firmware uses hserin to read multiple bytes or to wait for a byte, there is

no way to detect overrun and framing errors because firmware has no way to

read RCSTA after executing hserin but before reading RCREG. For some appli-

cations, detecting framing and overrun errors isn’t essential.

 After determining that a byte is available and before reading the byte, code can
check for overrun and framing errors.
unsigned char serial_in;

if DataRdyUSART()

{

// A character is available.

if (RCSTAbits.OERR == 1)

{

// Overrun error.

// Clear the error and re-enable the receiver.

RCSTAbits.CREN = 0;

RCSTAbits.CREN = 1;

}

if (RCSTAbits.FERR == 1)

{

// Framing error.

// Read the byte to clear the error but don't use the byte.

serial_in = getcUSART();

}

else

{

// A byte was received without error.

serial_in = getcUSART();

// Do something with the byte.

}

}

!      '    





A task loop is an endless loop that can perform serial-communications tasks and

any other tasks a device is responsible for. Firmware performs each task in