ex_slave.c

PIC单片机从SPI

///////////////////////////////////////////////////////////////////////////
////                         EX_SLAVE.C                                ////
////                                                                   ////
////  This program uses the PIC in I2C slave mode to emulate the       ////
////  24LC01 EEPROM. You can write to addresses 00h to 0Fh with it.    ////
////                                                                   ////
////  This program is to be used in conjunction with the ex_extee.c    ////
////  sample.  Use the "#include <2402.C>" or "#include <2401.c>".     ////
////  Only 16 bytes of address space are implemented, however.         ////
////                                                                   ////
////  If using a compiler version before 2.639 add "*0x14 = 0x3E;" to  ////
////  the begining of main(), and add "NOFORCE_SW" as the last         ////
////  parameter in the #use i2c directive.                             ////
////                                                                   ////
////  Jumpers:                                                         ////
////     PCM,PCH    pin C7 to RS232 RX, pin C6 to RS232 TX             ////
////                                                                   ////
////  This example will work with the PCM and PCH compilers.  The      ////
////  following conditional compilation lines are used to include a    ////
////  valid device for each compiler.  Change the device, clock and    ////
////  RS232 pins for your hardware if needed.                          ////
///////////////////////////////////////////////////////////////////////////
////        (C) Copyright 1996,2003 Custom Computer Services           ////
//// This source code may only be used by licensed users of the CCS    ////
//// C compiler.  This source code may only be distributed to other    ////
//// licensed users of the CCS C compiler.  No other use,              ////
//// reproduction or distribution is permitted without written         ////
//// permission.  Derivative programs created using this software      ////
//// in object code form are not restricted in any way.                ////
///////////////////////////////////////////////////////////////////////////


#if defined(__PCM__)
#include <16F877.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)

#elif defined(__PCH__)
#include <18F452.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#endif

#use i2c(SLAVE, SDA=PIN_C4, SCL=PIN_C3, address=0xa0)

BYTE address, buffer[0x10];

#INT_SSP
void ssp_interupt ()
{
   BYTE incoming, state;

	state = i2c_isr_state();

	if(state < 0x80)							//Master is sending data
	{
		incoming = i2c_read();
		if(state == 1)							//First received byte is address
			address = incoming;
		if(state == 2)							//Second received byte is data
			buffer[address] = incoming;
	}
	if(state == 0x80)							//Master is requesting data
	{
		i2c_write(buffer[address]);
	}
}

void main ()
{
   enable_interrupts(GLOBAL);
   enable_interrupts(INT_SSP);

   while (TRUE) {}
}