//----------------------------------------------------------------------------------
char sht_read_statusreg(void)
//----------------------------------------------------------------------------------
// reads the status register with checksum (8-bit)
{
unsigned char error=0;
unsigned char tmp = 0;
unsigned char bits = 8;
sht_crc_init();
sht_transstart(); //transmission start
error=sht_write_byte(STATUS_REG_R); //send command to sensor
sht_crc_shuffle_byte(STATUS_REG_R);
StatusReg =sht_read_byte(ACK); //read status register (8-bit)
sht_crc_shuffle_byte(StatusReg);
CheckSum =sht_read_byte(noACK); //read checksum (8-bit)
while( bits--)
{
tmp >>=1;
if( sht_crc & 0b10000000)
tmp |= 0b10000000;
sht_crc <<=1;
}
if (tmp != CheckSum) {
SHTdevice_table[CurrentSensorIndex].crc++;
error++;
}
return error; //error=1 in case of no response form the sensor
}
//----------------------------------------------------------------------------------
// writes the status register with checksum (8-bit)
//----------------------------------------------------------------------------------
char sht_write_statusreg(unsigned char *p_value)
{
unsigned char error=0;
sht_transstart(); //transmission start
error+=sht_write_byte(STATUS_REG_W);//send command to sensor
error+=sht_write_byte(*p_value); //send value of status register
return error; //error>=1 in case of no response form the sensor
}
//----------------------------------------------------------------------------------
// reads the status register with checksum (8-bit)
//----------------------------------------------------------------------------------
char sht_read_statusreg(unsigned char *p_value, unsigned char *p_checksum)
{
unsigned char error=0;
sht_transstart(); //transmission start
error=sht_write_byte(STATUS_REG_R); //send command to sensor
*p_value=sht_read_byte(ACK); //read status register (8-bit)
*p_checksum=sht_read_byte(noACK); //read checksum (8-bit)
return error; //error=1 in case of no response form the sensor
}
//----------------------------------------------------------------------------------
// start measurement (humidity/temperature)
//----------------------------------------------------------------------------------
char sht_measure_start(unsigned char mode)
{
sht_transstart(); // transmission start
switch(mode) { // send command to sensor
case TEMP: return(sht_write_byte(MEASURE_TEMP)); //break;
case HUMI: return(sht_write_byte(MEASURE_HUMI)); //break;
default: break;
}
return 1; // error
}
//----------------------------------------------------------------------------------
unsigned char sht_write_statusreg(unsigned char *p_sht_value, unsigned char pin)
//----------------------------------------------------------------------------------
// writes the status register with checksum (8-bit)
{
unsigned char error=0;
sht_transstart(pin); //transmission start
error+=sht_write_byte(STATUS_REG_W, pin);//send command to sensor
error+=sht_write_byte(*p_sht_value, pin); //send value of status register
return error; //error>=1 in case of no response form the sensor
}
void sht_connectionreset(void)
{
unsigned char i;
SHT_DATA_OUT(0); SHT_SCK(0); //Initial state
//for(i=0;i<9;i++) //9 SCK cycles
for(i=9;i!=0;i--) //9 SCK cycles (detecting 0 is easier - says TI)
{
SHT_SCK(1);
delay_us(1);
SHT_SCK(0);
}
sht_transstart(); //transmission start
}
//----------------------------------------------------------------------------------
char sht_measure(unsigned char mode)
//----------------------------------------------------------------------------------
// makes a measurement (humidity/temperature) with checksum
{
unsigned error=0;
unsigned int i;
unsigned char LSB;
unsigned char MSB;
unsigned char tmp = 0;
unsigned char bits = 8;
sht_crc_init();
sht_transstart(); //transmission start
switch(mode){ //send command to sensor
case TEMP : error+=sht_write_byte(MEASURE_TEMP); sht_crc_shuffle_byte(MEASURE_TEMP);break;
case HUMI : error+=sht_write_byte(MEASURE_HUMI); sht_crc_shuffle_byte(MEASURE_HUMI);break;
default : break;
}
for (i=0;i<40000;i++) {
if(DATA_IN==0) {
break; //wait until sensor has finished the measurement
}
Delay100TCYx(4); //50 us
}
if(DATA_IN)
{
error+=1; // or timeout (~2 sec.) is reached
}
MSB = sht_read_byte(ACK); //read the first byte (MSB)
sht_crc_shuffle_byte(MSB);
LSB = sht_read_byte(ACK); //read the second byte (LSB)
sht_crc_shuffle_byte(LSB);
CurrentValue = MSB * 256 + LSB;
CheckSum = sht_read_byte(noACK); //read checksum
while( bits--)
{
tmp >>=1;
if( sht_crc & 0b10000000)
tmp |= 0b10000000;
sht_crc <<=1;
}
if (tmp != CheckSum) {
SHTdevice_table[CurrentSensorIndex].crc++;
return 1;
}
return error;
}
void sht_connectionreset( void )
{
unsigned char i;
// Make RC5 input
TRISCbits.TRISC5 = 1;
PORTCbits.RC5 = 1; // DATA = 1
PORTCbits.RC3 = 0; // CLK = 0
for( i = 0; i < 9; i++ ) { // 9 SCK cycles
PORTCbits.RC3 = 1; // CLK = 1
PORTCbits.RC3 = 0; // CLK = 0
}
sht_transstart(); // transmission start
}
//----------------------------------------------------------------------------------
void sht_connectionreset(void)
//----------------------------------------------------------------------------------
// communication reset: DATA-line=1 and at least 9 SCK cycles followed by transstart
// _____________________________________________________ ________
// DATA: |_______|
// _ _ _ _ _ _ _ _ _ ___ ___
// SCK : __| |__| |__| |__| |__| |__| |__| |__| |__| |______| |___| |______
{
unsigned char i;
DATA(1);//TRISCbits.RC5 = 1;
Delay10TCYx(2*sht_speed);
SCK(0); //Initial state
Delay10TCYx(2*sht_speed);
for(i=0;i<9;i++) //9 SCK cycles
{ SCK(1);
Delay10TCYx(2*sht_speed);
SCK(0);
Delay10TCYx(2*sht_speed);
}
sht_transstart(); //transmission start
}
char sht_measure( unsigned char *p_value, unsigned char *p_checksum, unsigned char mode )
{
unsigned error=0;
unsigned long i;
sht_transstart(); // transmission start
switch( mode ) { // send command to sensor
case SHT_MODE_TEMP:
error += sht_write_byte( MEASURE_TEMP );
break;
case SHT_MODE_HUMI:
error += sht_write_byte( MEASURE_HUMI );
break;
default:
break;
}
// wait until sensor has finished the measurement
sht_measure_timer = 0;
while ( sht_measure_timer < SHT_READ_TIMEOUT ) {
if ( 0 == ( PORTCbits.RC5 ) ) {
break;
}
}
if ( PORTCbits.RC5 ) { // or timeout (~2 sec.) is reached
error += 1;
}
*(p_value) = sht_read_byte( ACK ); // read the first byte (MSB)
*(p_value+1)= sht_read_byte( ACK ); // read the second byte (LSB)
*p_checksum = sht_read_byte( noACK ); // read checksum
return error;
}
//----------------------------------------------------------------------------------
void sht_connectionreset(unsigned char pin)
//----------------------------------------------------------------------------------
// communication reset: DATA-line=1 and at least 9 SCK cycles followed by transstart
{
unsigned char i;
MAKE_SHT_DATA_PIN_OUTPUT(pin);
asm volatile ("nop"::);
SET_SHT_DATA(pin); CLEAR_SHT_SCK; //Initial state
for(i=0;i<9;i++) //9 SCK cycles
{
SET_SHT_SCK;
asm volatile ("nop"::);
asm volatile ("nop"::);
CLEAR_SHT_SCK;
asm volatile ("nop"::);
asm volatile ("nop"::);
}
sht_transstart(pin); //transmission start
}
