// write to an address
void I2Cwrite(char addr, char subaddr, char value)
{
char tmp;
i2c_start();
tmp = send_i2c_byte(addr);
tmp = send_i2c_byte(subaddr);
tmp = send_i2c_byte(value);
reset_i2c_bus();
}
//read from an address
char I2Cread(char addr, char subaddr)
{
char temp;
i2c_start();
send_i2c_byte(addr);
send_i2c_byte(subaddr);
microcontroller_delay_us(10);
i2c_restart();
send_i2c_byte(addr | 0x01);
temp = i2c_read_byte();
reset_i2c_bus();
return temp;
}
/*
* Function: firmwareTest()
* --------------------
*
* Requests the firmare version from si7020. Function used to test i2c communication.
*
*/
void firmwareTest() {
i2c_start();
send_i2c_byte(0x80); // address +0 write
send_i2c_byte(0x84); /// FIRMWARE!!!!!!!!!
send_i2c_byte(0xB8); /// FIRMWARE!!!!!!!!!
//0x84 =0b10000100
//0xB8 =0b10111000
i2c_start(); /// FIRMWARE!!!!!!!!!
send_i2c_byte(0x81); /// FIRMWARE!!!!!!!!!
// cc3=i2c_read();
// i2c_stop();
}
/*
* Function: measureRH()
* --------------------
* Used to send the RH measurement command and read the result
*/
void measureRH() {
i2c_start();
send_i2c_byte(SI7020ADR_W); // address +0 write
send_i2c_byte(MEASURE_HUM_HOLD_CMD); //0xE5 =0b11100101
i2c_repeatedStart();
send_i2c_byte(SI7020ADR_R); //adresss +1 read
i2c_mIdleI2C1();
hhLSB = i2c_read_ack();
i2c_ack();
i2c_mIdleI2C1();
i2c_ack();
hhMSB = i2c_read_ack();
i2c_mIdleI2C1(); /////////////////////// maybe?
i2c_nack();
i2c_stop();
humidityCode.b[0] = hhLSB;
humidityCode.b[1] = hhMSB;
}
/*
* Function: measureT()
* --------------------
* Used to send the temperature measurement command and read the result
*/
void measureT() {
i2c_start();
send_i2c_byte(SI7020ADR_W); // address +0 write
send_i2c_byte(MEASURE_TEMP_HOLD_CMD); //0xE3 =0b11100011
i2c_repeatedStart();
//i2c_start();
send_i2c_byte(SI7020ADR_R); //adresss +1 read
i2c_mIdleI2C1();
ttLSB = i2c_read_ack();
i2c_ack();
i2c_mIdleI2C1();
i2c_ack();
ttMSB = i2c_read_ack();
i2c_mIdleI2C1(); /////////////////////// maybe?
i2c_nack();
i2c_stop();
temperatureCode.b[0] = ttLSB;
temperatureCode.b[1] = ttMSB;
}
/*
* Function: getLastTemp()
* --------------------
* Used to retrieve last temperature measurement, idea is to save some time on
* conversion-> because SI7020 does relative humidity(RH) measurement it also measures
* temperature.
*/
void getLastTemp() {
i2c_start();
send_i2c_byte(SI7020ADR_W); // address +0 write
send_i2c_byte(READ_LAST_TEMP_CMD);
i2c_repeatedStart();
//i2c_start();
send_i2c_byte(SI7020ADR_R); //adresss +1 read
i2c_mIdleI2C1();
ttLSB = i2c_read_ack();
i2c_ack();
i2c_mIdleI2C1();
i2c_ack();
ttMSB = i2c_read_ack();
i2c_mIdleI2C1(); /////////////////////// maybe?
i2c_nack();
i2c_stop();
temperatureCode.b[0] = ttLSB;
temperatureCode.b[1] = ttMSB;
}
