How to clear RCREG

[HenrikOlsson]

Hi,
I thought HSERIN flushed the buffer first thing - apparently not.... Or are you just concerned that what you describe MIGHT happen if you DON'T clear the buffer before issuing a HSERIN?

A quick look in the datasheet for a 18F25K22 doesn't really say (or I missed it) if RCREG is writable so I can't really answer that with certainty but how it's "usually" done is to read it untill there's no more data available.

RC1IF VAR PIR1.5   ' Alias to USART receive interrupt flag

WHILE RC1IF
  Dummy = RCREG1
WEND

Or, since the FIFO is only two bytes deep, simply

Dummy = RCREG1
Dummy = RCREG1

/Henrik.

[xapmanis]

Thank you for the info Henrik.

I thought HSERIN flushed the buffer first thing - apparently not

I used my pic as a Command Line Editor to communicate from my PC Hyperterminal with many Devices. In the past i did care only for debuging those devices so i never went into trouble looking "why the HECK" those two Bytes pop up into my array and as a result to my Hyperterminal.
Since i have to make a more stable program with many "Command Messages" comming via SMS i tried to debug those two Bytes.
After a lot of search and testing the result was that Hserin [Str Arrayvar\n\c] saves the string until the "c" char received but it doesn't clear the RCREGx after so if Hserin is used again, the last 2 Bytes that remain in the RCREGx become the 2 first received Bytes !

I believe RCREGx is both Readable/Writable register because all the codes bellow worked fine.

WHILE RC1IF
  Dummy = RCREG1
WEND

Dummy = RCREG1
Dummy = RCREG1

RCREG1= 0
RCREG1= 0

Best Regards, Kostas.

[richard]

I tend to use

RCSTA.4=0 ; (cren)
RCSTA.4=1

to clear buffer overrun etc

but now I wonder if it clears rcreg