int OWReadByte(void)
{
int loop, result = 0;
for (loop = 0; loop < 8; loop++) {
result >>= 1;
if (OWReadBit())
result |= 0x80;
}
return result;
}
//-----------------------------------------------------------------------------
// Read 1-Wire data byte and return it
//
int OWReadByte(void)
{
int loop, result=0;
for (loop = 0; loop < 8; loop++)
{
// shift the result to get it ready for the next bit
result >>= 1;
// if result is one, then set MS bit
if (OWReadBit())
result |= 0x80;
}
return result;
}
//-----------------------------------------------------------------------------
// Write a 1-Wire data byte and return the sampled result.
//
int OWTouchByte(int data)
{
int loop, result=0;
for (loop = 0; loop < 8; loop++)
{
// shift the result to get it ready for the next bit
result >>= 1;
// If sending a '1' then read a bit else write a '0'
if (data & 0x01)
{
if (OWReadBit())
result |= 0x80;
}
else
OWWriteBit(0);
// shift the data byte for the next bit
data >>= 1;
}
return result;
}
//--------------------------------------------------------------------------
//! Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
//! search state.
//! @return TRUE : device found, ROM number in ROM_NO buffer
//! FALSE : device not found, end of search
//
int OWSearch()
{
int id_bit_number;
int last_zero, rom_byte_number, search_result;
int id_bit, cmp_id_bit;
uchar rom_byte_mask, search_direction;
// initialize for search
id_bit_number = 1;
last_zero = 0;
rom_byte_number = 0;
rom_byte_mask = 1;
search_result = 0;
crc8 = 0;
// if the last call was not the last one
if (!LastDeviceFlag)
{
// 1-Wire reset
if (!OWReset())
{
// reset the search
LastDiscrepancy = 0;
LastDeviceFlag = FALSE;
LastFamilyDiscrepancy = 0;
return FALSE;
}
// issue the search command
OWWriteByte(0xF0);
// loop to do the search
do
{
// read a bit and its complement
id_bit = OWReadBit();
cmp_id_bit = OWReadBit();
// check for no devices on 1-wire
if ((id_bit == 1) && (cmp_id_bit == 1))
break;
else
{
// all devices coupled have 0 or 1
if (id_bit != cmp_id_bit)
search_direction = id_bit; // bit write value for search
else
{
// if this discrepancy if before the Last Discrepancy
// on a previous next then pick the same as last time
if (id_bit_number < LastDiscrepancy)
search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
else
// if equal to last pick 1, if not then pick 0
if (id_bit_number == LastDiscrepancy)
search_direction = 1;
else
search_direction = 0;
// if 0 was picked then record its position in LastZero
if (search_direction == 0)
{
last_zero = id_bit_number;
// check for Last discrepancy in family
if (last_zero < 9)
LastFamilyDiscrepancy = last_zero;
}
}
// set or clear the bit in the ROM byte rom_byte_number
// with mask rom_byte_mask
if (search_direction == 1)
ROM_NO[rom_byte_number] |= rom_byte_mask;
else
ROM_NO[rom_byte_number] &= ~rom_byte_mask;
// serial number search direction write bit
OWWriteBit(search_direction);
// increment the byte counter id_bit_number
// and shift the mask rom_byte_mask
id_bit_number++;
rom_byte_mask <<= 1;
// if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
if (rom_byte_mask == 0)
{
docrc8(ROM_NO[rom_byte_number]); // accumulate the CRC
rom_byte_number++;
rom_byte_mask = 1;
}
}
}
while(rom_byte_number < 8); // loop until through all ROM bytes 0-7
// if the search was successful then
if (!((id_bit_number < 65) || (crc8 != 0)))
{
// search successful so set LastDiscrepancy,LastDeviceFlag,search_result
LastDiscrepancy = last_zero;
// check for last device
if (LastDiscrepancy == 0)
LastDeviceFlag = TRUE;
search_result = TRUE;
}
}
// if no device found then reset counters so next 'search' will be like a first
if (!search_result || !ROM_NO[0])
{
LastDiscrepancy = 0;
LastDeviceFlag = FALSE;
LastFamilyDiscrepancy = 0;
search_result = FALSE;
}
return search_result;
}
/**
* @brief Reads temperature on a ds1820 temperature sensor
* @param temperature Pointer to the measured temperature
* @return 0 if temperature read successfully
*/
int bbb_one_wire_DS1820_read(float* temperature, string* data)
{
/*
int get[10];
char temp_lsb,temp_msb;
int k;
char temp_f,temp_c;
OWTouchReset();
OWWriteByte(0xCC); //Skip ROM
OWWriteByte(0x44); // Start Conversion
tickDelay(5);
OWTouchReset();
OWWriteByte(0xCC); // Skip ROM
OWWriteByte(0xBE); // Read Scratch Pad
for (k=0;k<9;k++)
{
get[k] = OWReadByte();
}
cout << "ScratchPAD DATA = " << get[8] << get[7] << get[6] << get[5] << get[4] << get[3] << get[2] << get[1] << get[0] << endl;
temp_msb = get[1]; // Sign byte + lsbit
temp_lsb = get[0]; // Temp data plus lsb
if (temp_msb <= 0x80)
{
temp_lsb = (temp_lsb/2);
} // shift to get whole degree
temp_msb = temp_msb & 0x80; // mask all but the sign bit
if (temp_msb >= 0x80)
{
temp_lsb = (~temp_lsb)+1;
} // twos complement
if (temp_msb >= 0x80)
{
temp_lsb = (temp_lsb/2);
}// shift to get whole degree
if (temp_msb >= 0x80)
{
temp_lsb = ((-1)*temp_lsb);
} // add sign bit
//cout << "TempC= " << (int)temp_lsb << " degrees C" << endl;// print temp. C
*temperature = (int)temp_lsb;
return 1;
*/
int i = 0;
int a = 1;
unsigned short dataCRC16;
OWTouchReset();
OWWriteByte(SKIP_ROM);
OWWriteByte(CONVERT_T);
while(a)
{
tickDelay(5);
if(OWReadBit())
a = 0;
}
OWTouchReset();
OWWriteByte(SKIP_ROM);
OWWriteByte(READ_SCRATCHPAD);
*temperature = OWReadByte() + (OWReadByte() << 8);
return 1;
/*
if(OWTouchReset())
return 0;
OWWriteByte(0xCC);
OWWriteByte(0xA5);
OWWriteByte((page << 5) & 0xFF);
OWWriteByte(0);
for(i = 0; i < 32; i++)
*data += OWReadByte() + "-";
OWWriteByte(0xFF);
*/
// return result;
}
