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i2c1.c
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i2c1.c
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#include "mcc.h"
#include "protocol.h"
#define I2C_SLAVE_ADDRESS 0x01
#define I2C_SLAVE_MASK 0x7F
#define DEFAULT 0x00
#define SET_VALUE 0x01
#define EXT_LENGTH 0x02
#define EXT_VALUE 0x03
typedef enum
{
SLAVE_NORMAL_DATA,
SLAVE_DATA_ADDRESS,
SLAVE_GENERAL_CALL,
} SLAVE_WRITE_DATA_TYPE;
/**
Section: Global Variables
*/
volatile uint8_t I2C_slaveWriteData = 0x55;
/**
Section: Local Functions
*/
void I2C1_StatusCallback(I2C1_SLAVE_DRIVER_STATUS i2c_bus_state);
void I2C1_Initialize(void)
{
// delay 2 sec for the master to finish its start up process
__delay_ms(2000);
// initialize the hardware
// R_nW write_noTX; P stopbit_notdetected; S startbit_notdetected; BF RCinprocess_TXcomplete; SMP Standard Speed; UA dontupdate; CKE disabled; D_nA lastbyte_address;
SSP1STAT = 0x80;
// SSPEN enabled; WCOL no_collision; CKP disabled; SSPM 7 Bit Polling; SSPOV no_overflow;
SSP1CON1 = 0x26;
// ACKEN disabled; GCEN enabled; PEN disabled; ACKDT acknowledge; RSEN disabled; RCEN disabled; ACKSTAT received; SEN enabled;
SSP1CON2 = 0x81;
// ACKTIM ackseq; SBCDE disabled; BOEN disabled; SCIE disabled; PCIE disabled; DHEN disabled; SDAHT 100ns; AHEN disabled;
SSP1CON3 = 0x00;
// SSPMSK 127;
SSP1MSK = (I2C_SLAVE_MASK << 1); // adjust UI mask for R/nW bit
// SSPADD 8;
SSP1ADD = (PROTOCOL_Read_Device_Address() << 1); // adjust UI address for R/nW bit
// clear the slave interrupt flag
PIR1bits.SSP1IF = 0;
// enable the master interrupt
PIE1bits.SSP1IE = 1;
}
void I2C1_ISR ( void )
{
uint8_t i2c_data = 0x55;
// NOTE: The slave driver will always acknowledge
// any address match.
PIR1bits.SSP1IF = 0; // clear the slave interrupt flag
i2c_data = SSP1BUF; // read SSPBUF to clear BF
if(1 == SSP1STATbits.R_nW)
{
if((1 == SSP1STATbits.D_nA) && (1 == SSP1CON2bits.ACKSTAT))
{
// callback routine can perform any post-read processing
I2C1_StatusCallback(I2C1_SLAVE_READ_COMPLETED);
}
else
{
// callback routine should write data into SSPBUF
I2C1_StatusCallback(I2C1_SLAVE_READ_REQUEST);
}
}
else if(0 == SSP1STATbits.D_nA)
{
// this is an I2C address
if(0x00 == i2c_data)
{
// this is the General Call address
I2C1_StatusCallback(I2C1_SLAVE_GENERAL_CALL_REQUEST);
}
else
{
// callback routine should prepare to receive data from the master
I2C1_StatusCallback(I2C1_SLAVE_WRITE_REQUEST);
}
}
else
{
I2C_slaveWriteData = i2c_data;
// callback routine should process I2C_slaveWriteData from the master
I2C1_StatusCallback(I2C1_SLAVE_WRITE_COMPLETED);
}
SSP1CON1bits.CKP = 1; // release SCL
}
void I2C1_StatusCallback(I2C1_SLAVE_DRIVER_STATUS i2c_bus_state)
{
static uint8_t slaveWriteType = SLAVE_NORMAL_DATA;
static uint8_t next = DEFAULT;
static uint8_t ext_len = 0;
static uint8_t ext_cnt = 0;
static char ext_buf[BUF_SIZE];
uint8_t *pdata;
switch (i2c_bus_state)
{
case I2C1_SLAVE_WRITE_REQUEST:
slaveWriteType = SLAVE_DATA_ADDRESS;
break;
case I2C1_SLAVE_GENERAL_CALL_REQUEST:
// the master will be sending general call data next
slaveWriteType = SLAVE_GENERAL_CALL;
break;
case I2C1_SLAVE_WRITE_COMPLETED:
switch(slaveWriteType)
{
case SLAVE_DATA_ADDRESS:
switch(next) {
case SET_VALUE:
PROTOCOL_SET(I2C_slaveWriteData);
next = DEFAULT;
break;
case DEFAULT:
switch(I2C_slaveWriteData) {
case STA_I2C:
PROTOCOL_STA();
break;
case STP_I2C:
PROTOCOL_STP();
break;
case SAV_I2C:
PROTOCOL_SAV();
break;
case INV_I2C:
PROTOCOL_INV();
break;
case RST_I2C:
PROTOCOL_RST();
break;
case SET_I2C:
next = SET_VALUE;
break;
case EXT_I2C:
next = EXT_LENGTH;
break;
}
break;
}
break;
case SLAVE_GENERAL_CALL:
if (I2C_slaveWriteData == PLG_I2C) {
SSP1CON2bits.GCEN = 0; // Disable General Call reception
PROTOCOL_Backplane_Slave_Enabled();
}
break;
case SLAVE_NORMAL_DATA:
switch(next) {
case EXT_LENGTH:
ext_len = I2C_slaveWriteData;
ext_cnt = 0;
next = EXT_VALUE;
break;
case EXT_VALUE:
ext_buf[ext_cnt++] = (char)I2C_slaveWriteData;
if (ext_cnt >= ext_len) {
if (!PROTOCOL_Read_Lock()) PROTOCOL_EXT(&ext_buf[0]);
next = DEFAULT;
}
break;
}
break;
default:
break;
}
slaveWriteType = SLAVE_NORMAL_DATA;
break;
case I2C1_SLAVE_READ_REQUEST:
switch (I2C_slaveWriteData)
{
case WHO_I2C:
SSP1BUF = PROTOCOL_I2C_WHO();
break;
case SEN_I2C:
pdata = PROTOCOL_I2C_SEN();
SSP1BUF = *pdata;
break;
case GET_I2C:
SSP1BUF = PROTOCOL_I2C_GET();
break;
}
break;
case I2C1_SLAVE_READ_COMPLETED:
break;
default:
break;
}
}