You don't specify which PIC you're using, but the UARTs tend to be
similar. From http://ww1.microchip.com/downloads/en/DeviceDoc/41350C.pdf,
we find:

16.1.2.4 Receive Interrupts
The RCIF interrupt flag bit of the PIR1 register is set
whenever the EUSART receiver is enabled and there is
an unread character in the receive FIFO. The RCIF
interrupt flag bit is read-only, it cannot be set or cleared
by software.

So, the RCIF=0 does nothing since the bit is read only. As others have
pointed out, there is a small FIFO in the UART. Because of this, I'd
change the if(RCIF) to while(RCIF). This will loop the routine that pulls
data from the UART until it is empty.

Finally, I like putting stuff from the UART ISR into a FIFO instead of a
linear buffer. In your non-interrupt code, you can pull data from the FIFO
and put it in the linear buffer for command interpretation at your
leisure. Putting data into the command interpreter buffer in the interrupt
requires the mainline code to act quickly on finding the end of command
before new data comes in and overwrites the command. Or, the command
interpreter could be in the ISR, but I like to keep them small and fast.
Of course, if the other end does not send a new command before getting a
response from this end, dropping directly into the linear buffer would
work fine.

In a recent project (movie theater closed captioning receiver), I have
packets of data coming in at 10kbps. It takes a variable amount of time to
deal with the data (most of the time just sticking it in a linear array,
but at the end of a packet doing a CRC check and then acting on it if
good), so the amount of data in the FIFO between the ISR and the mainline
code grows and shrinks as required so nothing gets lost.

Good luck!

Harold




>
>     if (RCIF)
>
>     {
>
>         char c = RCREG;
>
>
>
>         SerialRecordCharacter(c);
>
>
>
>         RCIF = 0;
>
>     }
>


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