Hello,

    anyone here have implemented a FIFO (First In, First Out) buffer for the
hardware USART of a PIC? I'm using a PIC16F877 and it does have to receive
USART and put it on a buffer for later processing.

    How do I implement it? I think I need two variables and an array, like:

        USART_BUFFER[8];    // for 8 locations
        USART_COUNTER;      // how many locations filled
        USART_POSITION;     // the last position filled

    When I receive a byte, I put it on (USART_POSITION + 1) and increment
USART_COUNTER.
    When USART_COUNTER = 8 , I generate an OVERRUN error.
    When USART_POSITION = 8, I make USART_POSITION = 0;

    This is so I don't have to waste time doing:
        USART_BUFFER[0] = USART_BUFFER[1];
        USART_BUFFER[1] = USART_BUFFER[2];
        USART_BUFFER[2] = USART_BUFFER[3];
        USART_BUFFER[3] = USART_BUFFER[4];
        USART_BUFFER[4] = USART_BUFFER[5];
        USART_BUFFER[5] = USART_BUFFER[6];
        USART_BUFFER[6] = USART_BUFFER[7];

    everytime I pull a byte.

    Is there an smarter way?

    Best regards,

    Brusque

-----------------------------------
Edson Brusque
Research and Development
C.I.Tronics Lighting Designers Ltda
(47) 323-2685  /  (47) 9993-6453
Blumenau  -  SC  -  Brazil
www.citronics.com.br
-----------------------------------

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