Brandon:
Here's some SPI code I wrote for the PIC16F877. Hope it works for you. If
you have any questions, let me know.
        Sam....
        "May the roof over your head
        never leak until it rains gold."

     ("`-''-/").___..--''"`-._
      `6_ 6  )   `-.  (     ).`-.__.`)
      (_Y_.)'  ._   )  `._ `. ``-..-'
    _..`--'_..-_/  /--'_.' ,'
   (il),-''  (li),'  ((!.-'


// *****************************************************************
// spi.c
//
// Author:  Sam R. Linder
//
//
// *****************************************************************


// external functions


// external global variables


// internal functions
unsigned char ReadByteSPI(void);
void WriteByteSPI(unsigned char writebyte);


// global variables
unsigned char rdataval;
unsigned char wdataval;
unsigned char loopcount;


//*****************
// Bit Declarations
//*****************
// SPIPORT = Port-C
// SPICLK_OUT = pin-3
// SPIDATA_IN = pin-4
// SPIDATA_OUT = pin-5
#define SCLK    SPIPORT,SPICLK_OUT
#define DATAIN  SPIPORT,SPIDATA_IN
#define DATAOUT SPIPORT,SPIDATA_OUT



unsigned char
ReadByteSPI(void)
{
#asm
    CLRF    STATUS                  // select bank-0
    clrf    _rdataval
    movlw   08                      // set loop count
    movwf   _loopcount              // save it
    bcf     STATUS,C                // clear Carry

R0:
    bsf     SCLK                    // set SCLK high
    bcf     SCLK                    // set SCLK low
    bcf     STATUS,C                // clear Carry
    btfsc   SPIPORT,SPIDATA_IN
    bsf     STATUS,C                // set Carry
    rlf     _rdataval,f             // rotate Carry bit into memory location
    decfsz  _loopcount,f            // decrement loop count, skip next line
if zero (we're done)
    goto    R0                      // else loop back to read next data bit
#endasm
    return (rdataval);
} // end of ReadByteSPI()



void
WriteByteSPI(unsigned char dataval)
{
#asm
    clrf    STATUS              // select bank-0
    movwf   _wdataval           // save data byte to write
    movlw   08                  // set loop count
    movwf   _loopcount          // save it
    bcf     STATUS,C            // clear Carry

W0:
    rlf     _wdataval,f         // rotate msb of _zdataval into Carry

    bcf     DATAOUT             // assume bit = 0 (set DATAOUT low)
    btfsc   STATUS,C            // test Carry bit (skip next line if Carry =
0)
    bsf     DATAOUT             // set DATAOUT high
    bsf     SCLK                // set SCLK high
    bcf     SCLK                //   then low
    decfsz  _loopcount,f        // decrement loop count, skip next line if
zero (we're done)
    goto   W0                   // else loop back to output next data bit
#endasm
} // end of WriteByteSPI()

// end of module spi.c


-----Original Message-----
From: Brandon Fosdick [mailto:bfoz@GLUE.UMD.EDU]
Sent: Sunday, August 05, 2001 2:03 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: [PIC]: Need SPI code for 16F877


As I've mentioned before, I'm trying to use the MCP2510 in a project.
The SPI module on the 16F877 is driving me crazy. Does anybody have code
for it that I can use? Or even just some helpful hints? I'm about ready
to forget the hardware module and just bit-bang it, but I didn't see any
code on piclist for that either. A quick search of google didn't provide
any usefull answers.

I think I can TX a byte by just loading it into SSPBUF and then waiting
for it to leave. But I have no idea how to get the thing to receive a
byte. I keep getting the last byte that I wrote to SSPBUF.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics