Regarding overwriting the buffer with new data when using a static
buffer. What I do currently is something along the lines of this:

void processCommands()
{
  char tmpBuf[SERIAL_BUFFER_SIZE + 1];
  RCIE =3D 0;
  memcpy(tmpBuf, __serial.buf, SERIAL_BUFFER_SIZE + 1); // buffer
includes a "silent" extra byte to ensure a 0 terminator is always
available
  RCIE =3D 1;

  .. process tmpBu ..
}

Though the fifo seems a better option since you don't have to disable
the interrupt even for a moment. The only down side is the extra
overhead of comparing the pointers to check for a wrap around, since I
would still need to copy it into another buffer for the string
comparisons when finding a command. Though it's a minor overhead given
the large benefits for an asynchronous protocol.

Quintin Beukes



On Fri, Oct 9, 2009 at 10:20 PM, Quintin Beukes <quintin@last.za.net> wrote:
> Thanks again.
>
> Funny enough about an hour before I sent this e-mail I was
> contemplating alternatives. The head/tail index was actually something
> I though up there (though I was thinking pointers it's technically the
> same thing).
>
> Quintin Beukes
>
>
>
> On Fri, Oct 9, 2009 at 9:11 PM, Harold Hallikainen
> <harold@hallikainen.org> wrote:
>>
>>> Quintin Beukes wrote:
>>>> Re. your FIFO tip? How do you implement this fifo?
>>>
>>> My PIC development environment (http://www.embedinc.com/pic) includes
>>> template modules for interrupt driven UART I/O with FIFOs. =A0The app c=
alls
>>> UART_PUT and UART_GET to send and receive bytes. =A0These routines acce=
ss
>>> the
>>> transmit and receive FIFOs, with the interrupt routine doing the work of
>>> accessing the UART hardware. =A0In a lot of cases you don't really need=
 a
>>> output FIFO, and you can change UART_PUT to spin on TXIF then write to
>>> TXREG.
>>
>> There was also an extensive discussion of this in July. See
>> http://www.nabble.com/Task-scheduling-in-Embedded-Systems-to24735436.htm=
l#a24768292
>>
>> Harold
>>
>>
>> --
>> FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
>> opportunities available!
>> --
>> http://www.piclist.com PIC/SX FAQ & list archive
>> View/change your membership options at
>> http://mailman.mit.edu/mailman/listinfo/piclist
>>
>

-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist