EX_SLAVE.C
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///////////////////////////////////////////////////////////////////////////
//// 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. ////
//// ////
//// 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 1996,2001 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 <16c74.h>
#fuses HS,NOWDT,NOPROTECT
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
#elif defined(__PCH__)
#include <18c452.h>
#fuses HS,NOPROTECT
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
#endif
#use i2c(SLAVE, SDA=PIN_C4, SCL=PIN_C3, address=0xa0)
typedef enum {NOTHING, CONTROL_READ,
ADDRESS_READ, READ_COMMAND_READ} I2C_STATE;
I2C_STATE fState;
byte address, buffer[0x10];
#INT_SSP
void ssp_interupt ()
{
byte incoming;
if (i2c_poll() == FALSE) {
if (fState == ADDRESS_READ) { //i2c_poll() returns false on the
i2c_write (buffer[address]);//interupt receiving the second
fState = NOTHING; //command byte for random read operation
}
}
else {
incoming = i2c_read();
if (fState == NOTHING){
fState = CONTROL_READ;
}
else if (fState == CONTROL_READ) {
address = incoming;
fState = ADDRESS_READ;
}
else if (fState == ADDRESS_READ) {
buffer[address] = incoming;
fState = NOTHING;
}
}
}
void main ()
{
int i;
fState = NOTHING;
address = 0x00;
for (i=0;i<0x10;i++)
buffer[i] = 0x00;
enable_interrupts(GLOBAL);
enable_interrupts(INT_SSP);
while (TRUE) {}
}
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