/*---------------------------------------------------------------------------*/
static void
owwriteb(unsigned byte)
{
int i = 7;
do {
if(byte & 0x01) {
DS2411_OUTPUT();
OUTP_0();
udelay_tA();
OUTP_1(); /* Releases the bus */
udelay(tB);
} else {
OUTP_0();
udelay(tC);
OUTP_1(); /* Releases the bus */
udelay(tD);
}
if(i == 0) {
DS2411_INPUT();
return;
}
i--;
byte >>= 1;
} while(1);
}
/*---------------------------------------------------------------------------*/
static int
owreset(void)
{
int result;
OUTP_0();
udelay(tH);
OUTP_1(); /* Releases the bus */
udelay(tI);
result = INP();
udelay(tJ);
return result;
}
/*---------------------------------------------------------------------------*/
static unsigned
owreadb(void)
{
unsigned result = 0;
int i = 7;
do {
OUTP_0();
udelay_tA();
OUTP_1(); /* Releases the bus */
udelay(tE);
if(INP()) {
result |= 0x80; /* LSbit first */
}
udelay(tF);
if(i == 0) {
return result;
}
i--;
result >>= 1;
} while(1);
}
uint8_t DHT_Read_Data(uint16_t *temperature, uint16_t *humidity){
//data[5] is 8byte table where data come from DHT are stored
//laststate holds laststate value
//counter is used to count microSeconds
uint8_t data[5], laststate = 0, counter = 0, j = 0, i = 0;
//Clear array
data[0] = data[1] = data[2] = data[3] = data[4] = 0;
uint8_t volatile sreg;
sreg = SREG; /* Save status register before disabling interrupts. */
cli(); /* Disable interrupts. */
//Set pin Output
//Pin High
DHT_DRIVE();
mdelay(100); //Wait for 100mS
//Send Request Signal
//Pin Low
OUTP_0(); //20ms Low
mdelay(20);
//Pin High
OUTP_1();
udelay(40); //40us High
//Set pin Input to read Bus
//Set pin Input
DHT_RELEASE();
laststate=DHT_INP(); //Read Pin value
//Repeat for each Transistions
for (i=0; i<MAXTIMINGS; i++) {
//While state is the same count microseconds
//led1_on();
//led1_off();
while (laststate==DHT_INP()) {
udelay(1);
counter++;
if (counter>254) break;
}
if (counter>254) break;
//laststate==_BV(DHT_PIN) checks if laststate was High
//ignore the first 2 transitions which are the DHT Response
//if (laststate==_BV(DHT_PIN) && (i > 2)) {
if ((i&0x01) && (i > 2)) {
//Save bits in segments of bytes
//Shift data[] value 1 position left
//Example. 01010100 if we shift it left one time it will be
//10101000
data[j/8]<<=1;
if (counter >= 15) { //If it was high for more than 40uS
//led1_on();
data[j/8]|=1; //it means it is bit '1' so make a logic
//led1_off();
} //OR with the value (save it)
j++; //making an OR by 1 to this value 10101000
} //we will have the resault 10101001
//1 in 8-bit binary is 00000001
//j/8 changes table record every 8 bits which means a byte has been saved
//so change to next record. 0/8=0 1/8=0 ... 7/8=0 8/8=1 ... 15/8=1 16/8=2
laststate=DHT_INP(); //save current state
counter=0; //reset counter
}
SREG = sreg; /* Enable interrupts. */
//printf("HUM %d %d %d %d %d %d",data[0],data[1],data[2],data[3],data[4],(uint8_t)(data[0] + data[1] + data[2] + data[3]) );
//Check if data received are correct by checking the CheckSum
if ((uint8_t)(data[0] + data[1] + data[2] + data[3]) == data[4]) {
#ifdef DHT11
*humidity = data[0]*100;
*temperature = data[2]*100;
#else
*humidity = ((uint16_t)data[0]<<8 | data[1])*10;
*temperature = ((uint16_t)data[2]<<8 | data[3])*10;
#endif
return 0;
}else{
*humidity = 2;
*temperature = 2;
// uart_puts("\r\nCheck Sum Error");
}
return 0xff; // Check Sum Error
}
