void DS18B20ReadRom(u8 pin, u8 *romcode)
{
u8 i;
if (!OneWireReset(pin))
{
OneWireWrite(pin, READROM);
for (i = 0; i < 8; i++) // Reads the ROM Code from a device
romcode[i] = OneWireRead(pin);
}
}
/*JSON{
"type" : "method",
"class" : "OneWire",
"name" : "read",
"generate" : "jswrap_onewire_read",
"params" : [["count","JsVar","(optional) The amount of bytes to read"]],
"return" : ["JsVar","The byte that was read, or a Uint8Array if count was specified and >=0"]
}
Read a byte
*/
JsVar *jswrap_onewire_read(JsVar *parent, JsVar *count) {
Pin pin = onewire_getpin(parent);
if (!jshIsPinValid(pin)) return 0;
if (jsvIsNumeric(count)) {
JsVarInt c = jsvGetInteger(count);
JsVar *arr = jsvNewTypedArray(ARRAYBUFFERVIEW_UINT8, c);
if (!arr) return 0;
JsvArrayBufferIterator it;
jsvArrayBufferIteratorNew(&it, arr, 0);
while (c--) {
jsvArrayBufferIteratorSetByteValue(&it, (char)OneWireRead(pin, 8));
jsvArrayBufferIteratorNext(&it);
}
jsvArrayBufferIteratorFree(&it);
return arr;
} else {
return jsvNewFromInteger(OneWireRead(pin, 8));
}
}
u8 DS18B20Read(u8 pin, u8 num, u8 resolution, DS18B20_Temperature * t)
{
u8 res, busy = LOW;
u8 temp_lsb, temp_msb;
u16 temp;
switch (resolution)
{
case RES12BIT: res = 0b01100000; break; // 12-bit resolution
case RES11BIT: res = 0b01000000; break; // 11-bit resolution
case RES10BIT: res = 0b00100000; break; // 10-bit resolution
case RES9BIT: res = 0b00000000; break; // 9-bit resolution
default: res = 0b00000000; break; // 9-bit resolution
/// NB: The power-up default of these bits is R0 = 1 and R1 = 1 (12-bit resolution)
}
if (!DS18B20Configure(pin, num, 0, 0, res)) return FALSE; // no alarm
if (OneWireReset(pin)) return FALSE;
if (num == SKIPROM)
{
// Skip ROM, address all devices
OneWireWrite(pin, SKIPROM);
}
else
{
// Talk to a particular device
if (!DS18B20MatchRom(pin, num)) return FALSE;
}
OneWireWrite(pin, CONVERT_T); // Start temperature conversion
while (busy == LOW) // Wait while busy ( = bus is low)
busy = OneWireRead(pin);
if (OneWireReset(pin)) return FALSE;
if (num == SKIPROM)
{
// Skip ROM, address all devices
OneWireWrite(pin, SKIPROM);
}
else
{
// Talk to a particular device
if (!DS18B20MatchRom(pin, num)) return FALSE;
}
OneWireWrite(pin, READ_SCRATCHPAD);// Read scratchpad
temp_lsb = OneWireRead(pin); // byte 0 of scratchpad : temperature lsb
temp_msb = OneWireRead(pin); // byte 1 of scratchpad : temperature msb
if (OneWireReset(pin)) return FALSE;
// Calculation
// ---------------------------------------------------------------------
// Temperature Register Format
// BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
// LS BYTE 2^3 2^2 2^1 2^0 2^-1 2^-2 2^-3 2^-4
// BIT15 BIT14 BIT13 BIT12 BIT11 BIT10 BIT9 BIT8
// MS BYTE S S S S S 2^6 2^5 2^4
// S = SIGN
temp = temp_msb;
temp = (temp << 8) + temp_lsb; // combine msb & lsb into 16 bit variable
if (temp_msb & 0b11111000) // test if sign is set, i.e. negative
{
t->sign = 1;
temp = (temp ^ 0xFFFF) + 1; // 2's complement conversion
}
else
{
t->sign = 0;
}
t->integer = (temp >> 4) & 0x7F; // fractional part is removed, leaving only integer part
/*
t->fraction = 0; // fractional part
if (BitRead(temp, 0)) t->fraction += 625;
if (BitRead(temp, 1)) t->fraction += 1250;
if (BitRead(temp, 2)) t->fraction += 2500;
if (BitRead(temp, 3)) t->fraction += 5000;
*/
t->fraction = (temp & 0x0F) * 625;
t->fraction /= 100; // two digits after decimal
return TRUE;
}
u8 DS18B20ReadMeasure(u8 pin, u8 num, DS18B20_Temperature * t)
{
u8 res, busy = LOW;
u8 temp_lsb, temp_msb;
u16 temp;
if (OneWireReset(pin)) return FALSE;
if (num == SKIPROM)
{
// Skip ROM, address all devices
OneWireWrite(pin, SKIPROM);
}
else
{
// Talk to a particular device
if (!DS18B20MatchRom(pin, num)) return FALSE;
}
OneWireWrite(pin, READ_SCRATCHPAD);// Read scratchpad
temp_lsb = OneWireRead(pin); // byte 0 of scratchpad : temperature lsb
temp_msb = OneWireRead(pin); // byte 1 of scratchpad : temperature msb
if (OneWireReset(pin)) return FALSE;
// Calculation
// ---------------------------------------------------------------------
// Temperature Register Format
// BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
// LS BYTE 2^3 2^2 2^1 2^0 2^-1 2^-2 2^-3 2^-4
// BIT15 BIT14 BIT13 BIT12 BIT11 BIT10 BIT9 BIT8
// MS BYTE S S S S S 2^6 2^5 2^4
// S = SIGN
temp = temp_msb;
temp = (temp << 8) + temp_lsb; // combine msb & lsb into 16 bit variable
if (temp_msb & 0b11111000) // test if sign is set, i.e. negative
{
t->sign = 1;
temp = (temp ^ 0xFFFF) + 1; // 2's complement conversion
}
else
{
t->sign = 0;
}
t->integer = (temp >> 4) & 0x7F; // fractional part is removed, leaving only integer part
/*
t->fraction = 0; // fractional part
if (BitRead(temp, 0)) t->fraction += 625;
if (BitRead(temp, 1)) t->fraction += 1250;
if (BitRead(temp, 2)) t->fraction += 2500;
if (BitRead(temp, 3)) t->fraction += 5000;
*/
t->fraction = (temp & 0x0F) * 625;
t->fraction /= 100; // two digits after decimal
return TRUE;
}
/*JSON{
"type" : "method",
"class" : "OneWire",
"name" : "search",
"generate" : "jswrap_onewire_search",
"params" : [
["command","int32","(Optional) command byte. If not specified (or zero), this defaults to 0xF0. This can could be set to 0xEC to perform a DS18B20 'Alarm Search Command'"]
],
"return" : ["JsVar","An array of devices that were found"]
}
Search for devices
*/
JsVar *jswrap_onewire_search(JsVar *parent, int command) {
// search - code from http://www.maximintegrated.com/app-notes/index.mvp/id/187
Pin pin = onewire_getpin(parent);
if (!jshIsPinValid(pin)) return 0;
JsVar *array = jsvNewEmptyArray();
if (!array) return 0;
if (command<=0 || command>255)
command = 0xF0; // normal search command
// global search state
unsigned char ROM_NO[8];
int LastDiscrepancy;
int LastFamilyDiscrepancy;
int LastDeviceFlag;
// reset the search state
LastDiscrepancy = 0;
LastDeviceFlag = FALSE;
LastFamilyDiscrepancy = 0;
int search_result = true;
while (search_result) {
int id_bit_number;
int last_zero, rom_byte_number;
unsigned char 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;
// if the last call was not the last one
if (!LastDeviceFlag)
{
// 1-Wire reset
if (!OneWireReset(pin))
{
// reset the search
LastDiscrepancy = 0;
LastDeviceFlag = FALSE;
LastFamilyDiscrepancy = 0;
return array;
}
// issue the search command
OneWireWrite(pin, 8, (unsigned long long)command);
// loop to do the search
do
{
// read a bit and its complement
id_bit = (unsigned char)OneWireRead(pin, 1);
cmp_id_bit = (unsigned char)OneWireRead(pin, 1);
// 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] &= (unsigned char)~rom_byte_mask;
// serial number search direction write bit
OneWireWrite(pin, 1, search_direction);
// increment the byte counter id_bit_number
// and shift the mask rom_byte_mask
id_bit_number++;
rom_byte_mask = (unsigned char)(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)
{
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)))
{
// 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;
}
if (search_result) {
int i;
char buf[17];
for (i=0;i<8;i++) {
buf[i*2] = itoch((ROM_NO[i]>>4) & 15);
buf[i*2+1] = itoch(ROM_NO[i] & 15);
}
buf[16]=0;
jsvArrayPushAndUnLock(array, jsvNewFromString(buf));
}
NOT_USED(LastFamilyDiscrepancy);
}
return array;
}
u8 DS18B20Read(u8 pin, u8 num, u8 resolution, TEMPERATURE * t)
{
u8 res, busy = 0;
u8 temp_lsb, temp_msb;
switch (resolution)
{
case RES12BIT: res = Bin(01100000); break; // 12-bit resolution
case RES11BIT: res = Bin(01000000); break; // 11-bit resolution
case RES10BIT: res = Bin(00100000); break; // 10-bit resolution
case RES9BIT: res = Bin(00000000); break; // 9-bit resolution
default: res = Bin(00000000); break; // 9-bit resolution
/// NB: The power-up default of these bits is R0 = 1 and R1 = 1 (12-bit resolution)
}
DS18B20Configure(pin, num, 0, 0, res); // no alarm
if (OneWireReset(pin)) return FALSE;
if (num == SKIPROM)
{
// Skip ROM, address all devices
OneWireWrite(pin, SKIPROM);
}
else
{
// Talk to a particular device
DS18B20MatchRom(pin, num);
}
OneWireWrite(pin, CONVERT_T); // Start temperature conversion
while (busy == 0) // Wait while busy ( = bus is low)
busy = OneWireRead(pin);
if (OneWireReset(pin)) return FALSE;
if (num == SKIPROM)
{
// Skip ROM, address all devices
OneWireWrite(pin, SKIPROM);
}
else
{
// Talk to a particular device
DS18B20MatchRom(pin, num);
}
OneWireWrite(pin, READ_SCRATCHPAD);// Read scratchpad
temp_lsb = OneWireRead(pin); // byte 0 of scratchpad : temperature lsb
temp_msb = OneWireRead(pin); // byte 1 of scratchpad : temperature msb
OneWireReset(pin);
// Calculation
// ---------------------------------------------------------------------
// Temperature Register Format
// BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
// LS BYTE 2^3 2^2 2^1 2^0 2^-1 2^-2 2^-3 2^-4
// BIT15 BIT14 BIT13 BIT12 BIT11 BIT10 BIT9 BIT8
// MS BYTE S S S S S 2^6 2^5 2^4
// S = SIGN
if (temp_msb >= Bin(11111000)) // test if temperature is negative
{
t->sign = 1;
temp_msb -= Bin(11111000);
}
else
{
t->sign = 0;
}
t->integer = temp_lsb >> 4; // fractional part is removed, it remains only integer part
t->integer |= (temp_msb << 4); // integer part from temp_msb is added
t->fraction = 0; // fractional part (
if (BitRead(temp_lsb, 0)) t->fraction += 625;
if (BitRead(temp_lsb, 1)) t->fraction += 1250;
if (BitRead(temp_lsb, 2)) t->fraction += 2500;
if (BitRead(temp_lsb, 3)) t->fraction += 5000;
t->fraction /= 100; // two digits after decimal
return TRUE;
}
