[syntax=c]//------------------------------------------------------------------------
// Find the 'first' devices on the 1-Wire bus
// Return TRUE : device found, ROM number in ROM_NO buffer
// FALSE : no device present
//
int OWFirst(void)
{
// reset the search state
LastDiscrepancy = 0;
LastDeviceFlag = FALSE;
LastFamilyDiscrepancy = 0;
return OWSearch();
}
//------------------------------------------------------------------------
// Find the 'next' devices on the 1-Wire bus
// Return TRUE : device found, ROM number in ROM_NO buffer
// FALSE : device not found, end of search
//
int OWNext(void)
{
// leave the search state alone
return OWSearch();
}
//------------------------------------------------------------------------
// 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(void)
{
int id_bit_number;
int last_zero, rom_byte_number, search_result;
int id_bit, cmp_id_bit;
unsigned char 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(Search_ROM);
// 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
search_direction = (id_bit_number == LastDiscrepancy);
// 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)
{
OWCalcCRC(ROM_NO[rom_byte_number]); // accumulate the CRC
//OWcrc8(ROM_NO[rom_byte_number]); //druga metoda poszukiwania 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;
}
//--------------------------------------------------------------------------
// Verify the device with the ROM number in ROM_NO buffer is present.
// Return TRUE : device verified present
// FALSE : device not present
//
int OWVerify(void)
{
unsigned char rom_backup[8];
int i,rslt,ld_backup,ldf_backup,lfd_backup;
// keep a backup copy of the current state
for (i = 0; i < 8; i++)
rom_backup[i] = ROM_NO[i];
ld_backup = LastDiscrepancy;
ldf_backup = LastDeviceFlag;
lfd_backup = LastFamilyDiscrepancy;
// set search to find the same device
LastDiscrepancy = 64;
LastDeviceFlag = FALSE;
if (OWSearch())
{
// check if same device found
rslt = TRUE;
for (i = 0; i < 8; i++)
{
if (rom_backup[i] != ROM_NO[i])
{
rslt = FALSE;
break;
}
}
}
else
rslt = FALSE;
// restore the search state
for (i = 0; i < 8; i++)
ROM_NO[i] = rom_backup[i];
LastDiscrepancy = ld_backup;
LastDeviceFlag = ldf_backup;
LastFamilyDiscrepancy = lfd_backup;
// return the result of the verify
return(rslt);
}
//--------------------------------------------------------------------------
// Verify the device with the ROM number in EEPROM_ROM_NO buffer is present.
// Return TRUE : device verified present
// FALSE : device not present
//
int OWVerifyEEPROM(unsigned char *wsk)
{
unsigned char rom_backup[8];
int i,rslt,ld_backup,ldf_backup,lfd_backup;
// keep a backup copy of the current state
for (i = 0; i < 8; i++)
rom_backup[i] = eeprom_read_byte(wsk++);
ld_backup = LastDiscrepancy;
ldf_backup = LastDeviceFlag;
lfd_backup = LastFamilyDiscrepancy;
// set search to find the same device
LastDiscrepancy = 64;
LastDeviceFlag = FALSE;
if (OWSearch())
{
// check if same device found
rslt = TRUE;
for (i = 0; i < 8; i++)
{
if (rom_backup[i] != ROM_NO[i])
{
rslt = FALSE;
break;
}
}
}
else
rslt = FALSE;
// restore the search state
for (i = 0; i < 8; i++)
ROM_NO[i] = rom_backup[i];
LastDiscrepancy = ld_backup;
LastDeviceFlag = ldf_backup;
LastFamilyDiscrepancy = lfd_backup;
// return the result of the verify
return(rslt);
}
//--------------------------------------------------------------------------
// Setup the search to find the device type 'family_code' on the next call
// to OWNext() if it is present.
//
void OWTargetSetup(unsigned char family_code)
{
int i;
// set the search state to find SearchFamily type devices
ROM_NO[0] = family_code;
for (i = 1; i < 8; i++)
ROM_NO[i] = 0;
LastDiscrepancy = 64;
LastFamilyDiscrepancy = 0;
LastDeviceFlag = FALSE;
}
//--------------------------------------------------------------------------
// Setup the search to skip the current device type on the next call
// to OWNext().
//
void OWFamilySkipSetup(void)
{
// set the Last discrepancy to last family discrepancy
LastDiscrepancy = LastFamilyDiscrepancy;
LastFamilyDiscrepancy = 0;
// check for end of list
if (LastDiscrepancy == 0)
LastDeviceFlag = TRUE;
}[/syntax]Statystyki: Napisane przez janusz17 — 23 paź 2016, o 16:45
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