/*#--------------------------------------------------------------------------- *# *# FUNCTION NAME: I2C::sendAck *# *# DESCRIPTION : Send ACK on received data *# *#--------------------------------------------------------------------------*/ void i2c_sendack(void) { /* * enable output */ i2c_delay(CLOCK_LOW_TIME); i2c_dir_out(); /* * set ack pulse high */ i2c_data(I2C_DATA_LOW); /* * generate clock pulse */ i2c_delay(CLOCK_HIGH_TIME/6); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME/6); /* * reset data out */ i2c_data(I2C_DATA_HIGH); i2c_delay(CLOCK_LOW_TIME); i2c_dir_in(); }
void i2c_outbyte(unsigned char x) { int i; i2c_dir_out(); for (i = 0; i < 8; i++) { if (x & 0x80) { i2c_data(I2C_DATA_HIGH); } else { i2c_data(I2C_DATA_LOW); } i2c_delay(CLOCK_LOW_TIME/2); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME/2); x <<= 1; } i2c_data(I2C_DATA_LOW); i2c_delay(CLOCK_LOW_TIME/2); /* * enable input */ i2c_dir_in(); }
void i2c_start(void) { i2c_dir_out(); i2c_delay(CLOCK_HIGH_TIME/6); i2c_data(I2C_DATA_HIGH); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_data(I2C_DATA_LOW); i2c_delay(START_CONDITION_HOLD_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); }
void i2c_sendnack(void) { i2c_delay(CLOCK_LOW_TIME); i2c_dir_out(); i2c_data(I2C_DATA_HIGH); i2c_delay(CLOCK_HIGH_TIME/6); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_dir_in(); }
void i2c_stop(void) { i2c_dir_out(); i2c_clk(I2C_CLOCK_LOW); i2c_data(I2C_DATA_LOW); i2c_delay(CLOCK_LOW_TIME*2); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME*2); i2c_data(I2C_DATA_HIGH); i2c_delay(STOP_CONDITION_HOLD_TIME); i2c_dir_in(); }
unsigned char i2c_inbyte(void) { unsigned char aBitByte = 0; int i; /* Switch off I2C to get bit */ i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); /* Get bit */ aBitByte |= i2c_getbit(); /* Enable I2C */ i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); for (i = 1; i < 8; i++) { aBitByte <<= 1; /* Clock pulse */ i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); /* Switch off I2C to get bit */ i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); /* Get bit */ aBitByte |= i2c_getbit(); /* Enable I2C */ i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); } i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); /* * we leave the clock low, getbyte is usually followed * by sendack/nack, they assume the clock to be low */ i2c_clk(I2C_CLOCK_LOW); return aBitByte; }
// Send a stop sequence to I2C bus void i2c_stop(void) { i2c_dir_out(); i2c_clk(1); i2c_data(0); udelay(5); i2c_data(1); }
// Open the GPIOG dev int i2c_open(void) { i2c_fd = open("/dev/gpiog", O_RDWR); i2c_data(I2C_DATA_HIGH); i2c_dir_out(); i2c_clk(I2C_CLOCK_HIGH); i2c_data(I2C_DATA_HIGH); i2c_delay(100); return i2c_fd; }
unsigned char i2c_inbyte(void) { unsigned char aBitByte = 0; int i; i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); aBitByte |= i2c_getbit(); i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); for (i = 1; i < 8; i++) { aBitByte <<= 1; i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); aBitByte |= i2c_getbit(); i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); } i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); return aBitByte; }
unsigned char i2c_inbyte(void) { unsigned char aBitByte = 0; int i; /* Switch off I2C to get bit */ i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); /* Get bit */ aBitByte |= i2c_getbit(); /* Enable I2C */ i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); for (i = 1; i < 8; i++) { aBitByte <<= 1; /* Clock pulse */ i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); /* Switch off I2C to get bit */ i2c_disable(); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/2); /* Get bit */ aBitByte |= i2c_getbit(); /* Enable I2C */ i2c_enable(); i2c_delay(CLOCK_LOW_TIME/2); } i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); return aBitByte; }
int i2c_getack(void) { int ack = 1; i2c_dir_out(); i2c_data(I2C_DATA_HIGH); i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/4); i2c_clk(I2C_CLOCK_HIGH); #if 0 i2c_clk(1); i2c_data(1); i2c_data(1); i2c_disable(); i2c_dir_in(); #endif i2c_delay(CLOCK_HIGH_TIME/2); if (i2c_getbit()) ack = 0; i2c_delay(CLOCK_HIGH_TIME/2); if (!ack) { if (!i2c_getbit()) ack = 1; i2c_delay(CLOCK_HIGH_TIME/2); } #if 0 i2c_data(I2C_DATA_LOW); i2c_enable(); i2c_dir_out(); #endif i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_HIGH_TIME/4); i2c_dir_out(); i2c_data(I2C_DATA_HIGH); i2c_delay(CLOCK_LOW_TIME/2); return ack; }
int i2c_getack(void) { int ack = 1; /* * enable output */ i2c_dir_out(); /* * Release data bus by setting * data high */ i2c_data(I2C_DATA_HIGH); /* * enable input */ i2c_dir_in(); i2c_delay(CLOCK_HIGH_TIME/4); /* * generate ACK clock pulse */ i2c_clk(I2C_CLOCK_HIGH); /* * Use PORT PB instead of I2C * for input. (I2C not working) */ i2c_clk(1); i2c_data(1); /* * switch off I2C */ i2c_data(1); i2c_disable(); i2c_dir_in(); /* * now wait for ack */ i2c_delay(CLOCK_HIGH_TIME/2); /* * check for ack */ if(i2c_getbit()) ack = 0; i2c_delay(CLOCK_HIGH_TIME/2); if(!ack){ if(!i2c_getbit()) /* receiver pulld SDA low */ ack = 1; i2c_delay(CLOCK_HIGH_TIME/2); } /* * our clock is high now, make sure data is low * before we enable our output. If we keep data high * and enable output, we would generate a stop condition. */ i2c_data(I2C_DATA_LOW); /* * end clock pulse */ i2c_enable(); i2c_dir_out(); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_HIGH_TIME/4); /* * enable output */ i2c_dir_out(); /* * remove ACK clock pulse */ i2c_data(I2C_DATA_HIGH); i2c_delay(CLOCK_LOW_TIME/2); return ack; }
/*#--------------------------------------------------------------------------- *# *# FUNCTION NAME: i2c_readreg *# *# DESCRIPTION : Reads a value from the decoder registers. *# *#--------------------------------------------------------------------------*/ unsigned char i2c_readreg(unsigned char theSlave, unsigned char theReg) { unsigned char b = 0; int error, cntr = 3; unsigned long flags; do { error = 0; /* * we don't like to be interrupted */ save_flags(flags); cli(); /* * generate start condition */ i2c_start(); /* * dummy preamble */ i2c_outbyte(0x01); i2c_data(I2C_DATA_HIGH); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); /* Dummy Acknowledge */ i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_LOW_TIME); /* Repeated Start Condition */ i2c_data(I2C_DATA_LOW); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_start(); /* * send slave address */ i2c_outbyte(theSlave); /* * wait for ack */ if(!i2c_getack()) error = 1; /* * now select register */ i2c_dir_out(); i2c_outbyte(theReg); /* * now it's time to wait for ack */ if(!i2c_getack()) error = 1; /* * repeat start condition */ i2c_delay(CLOCK_LOW_TIME); i2c_start(); /* * send slave address */ i2c_outbyte(theSlave | 0x01); /* * wait for ack */ if(!i2c_getack()) error = 1; /* * fetch register */ b = i2c_inbyte(); /* * send Ack */ i2c_sendack(); /* * end sequence */ i2c_stop(); /* * enable interrupt again */ restore_flags(flags); } while(error && cntr--); return b; }
/*#--------------------------------------------------------------------------- *# *# FUNCTION NAME: i2c_writereg *# *# DESCRIPTION : Writes a value to an I2C device *# *#--------------------------------------------------------------------------*/ int i2c_writereg(unsigned char theSlave, unsigned char theReg, unsigned char theValue) { int error, cntr = 3; unsigned long flags; do { error = 0; /* * we don't like to be interrupted */ save_flags(flags); cli(); /* * generate start condition */ i2c_start(); /* * dummy preamble */ i2c_outbyte(0x01); i2c_data(I2C_DATA_HIGH); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_HIGH_TIME); /* Dummy Acknowledge */ i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_clk(I2C_CLOCK_HIGH); i2c_delay(CLOCK_LOW_TIME); /* Repeated Start Condition */ i2c_data(I2C_DATA_LOW); i2c_delay(CLOCK_HIGH_TIME); i2c_clk(I2C_CLOCK_LOW); i2c_delay(CLOCK_LOW_TIME); i2c_start(); /* * send slave address */ i2c_outbyte(theSlave); /* * wait for ack */ if(!i2c_getack()) error = 1; /* * now select register */ i2c_dir_out(); i2c_outbyte(theReg); /* * now it's time to wait for ack */ if(!i2c_getack()) error |= 2; /* * send register register data */ i2c_outbyte(theValue); /* * now it's time to wait for ack */ if(!i2c_getack()) error |= 4; /* * end byte stream */ i2c_stop(); /* * enable interrupt again */ restore_flags(flags); } while(error && cntr--); i2c_delay(CLOCK_LOW_TIME); return -error; }
unsigned char i2c_inbyte(void) { unsigned char aBitByte = 0; int i; int iaa; /* * enable output */ i2c_dir_out(); /* * Release data bus by setting * data high */ i2c_data(I2C_DATA_HIGH); /* * enable input */ i2c_dir_in(); /* * Use PORT PB instead of I2C * for input. (I2C not working) */ i2c_clk(1); i2c_data(1); /* * get bits */ for (i = 0; i < 8; i++) { i2c_delay(CLOCK_LOW_TIME/2); /* * low clock period */ i2c_clk(I2C_CLOCK_HIGH); /* * switch off I2C */ i2c_data(1); i2c_disable(); i2c_dir_in(); /* * wait before getting bit */ i2c_delay(CLOCK_HIGH_TIME/2); aBitByte = (aBitByte << 1); iaa = i2c_getbit(); aBitByte = aBitByte | iaa ; /* * wait */ i2c_delay(CLOCK_HIGH_TIME/2); /* * end clock puls */ i2c_enable(); i2c_dir_out(); i2c_clk(I2C_CLOCK_LOW); /* * low clock period */ i2c_delay(CLOCK_LOW_TIME/2); } i2c_dir_out(); return aBitByte; }