feat: Improve DS1820 driver

New features:
* Handle all types of DS1820 tempature sensors by detecting the family of the sensor and calculating the temperature accordingly
* Clean up some log prints
* Set the channel value with current temperature
* Update the reading every second instead of every 15s

src/driver/drv_ds1820_simple.c

@@ -6,6 +6,7 @@ static int Pin;
 static int t=-127;
 static int errcount=0;
 static int lastconv; // secondsElapsed on last successfull reading
+static uint8_t ds18_family = 0;
 
 
 // usleep adopted from DHT driver
@@ -366,7 +367,109 @@ void DS1820_AppendInformationToHTTPIndexPage(http_request_t *request)
  hprintf255(request, "<h5>DS1820 Temperature: %.2f C (read %i secs ago)</h5>",(float)t/100, g_secondsElapsed-lastconv);
 }
 
+// Adapted from Arduino OneWire library
+int DS1820_DiscoverFamily() {
+ uint8_t id_bit_number;
+ uint8_t last_zero, rom_byte_number;
+ int search_result;
+ uint8_t 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 = false;
+
+ uint8_t LastDiscrepancy = 0;
+ uint8_t LastFamilyDiscrepancy = 0;
+
+ char ROM_NO[8];
+ for (int i = 0; i < 8; i++) ROM_NO[i] = 0;
+
+ // 1-Wire reset
+ if (!OWReset(Pin)) {
+ addLogAdv(LOG_DEBUG, LOG_FEATURE_CFG, "DS1820 - Discover -- No device - Pin %i", Pin);
+ return false;
+ }
+
+ OWWriteByte(Pin,0xF0);
+
+ // loop to do the search
+ do
+ {
+ // read a bit and its complement
+ id_bit = OWReadBit(Pin);
+ cmp_id_bit = OWReadBit(Pin);
+
+ // 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(Pin, 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) {
+ 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
+ search_result = true;
+ }
+
+ // if no device found then reset counters so next 'search' will be like a first
+ if (!search_result || !ROM_NO[0]) {
+ addLogAdv(LOG_DEBUG, LOG_FEATURE_CFG, "DS1820 - Discover -- Search failed",Pin);
+ } else {
+ ds18_family = ROM_NO[0];
+ addLogAdv(LOG_DEBUG, LOG_FEATURE_CFG, "DS1820 - Discover -- Found device - %x%x%x%x%x%x%x%x",Pin,
+ ROM_NO[0], ROM_NO[1], ROM_NO[2], ROM_NO[3], ROM_NO[4], ROM_NO[5], ROM_NO[6], ROM_NO[7]);
+ }
+ return search_result;
+}
 
 void DS1820_OnEverySecond() {
 
@@ -379,10 +482,6 @@ void DS1820_OnEverySecond() {
  // if (dsread == 1 && g_secondsElapsed % 5 == 2) {
  // better if we don't use parasitic power, we can check if conversion is ready 
  if (dsread == 1 && DS1820TConversionDone(Pin) == 1) {
-
- uint8_t Low=0,High=0,negative=0;
- int Val,Tc;
-
  if (OWReset(Pin) == 0) addLogAdv(LOG_ERROR, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Reset failed",Pin); 
  OWWriteByte(Pin,0xCC);
  OWWriteByte(Pin,0xBE);
@@ -403,33 +502,37 @@ void DS1820_OnEverySecond() {
  } 
  else
  { 
- Low = scratchpad[0];
- High = scratchpad[1];
+ int16_t raw = (scratchpad[1] << 8) | scratchpad[0];
+
+ if (ds18_family == 0x10) { // DS18S20 or old DS1820
+ int16_t dT = 128 * (scratchpad[7] - scratchpad[6]);
+ dT /= scratchpad[7];
+ raw = 64 * (raw & 0xFFFE) - 32 + dT;
+ addLogAdv(LOG_DEBUG, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Family %x, raw %i, count_remain %i, count_per_c %i, dT %i",Pin, ds18_family, raw, scratchpad[6], scratchpad[7], dT);
+ } else {
+ uint8_t cfg = scratchpad[4] & 0x60;
+ if (cfg == 0x00) raw = raw & ~7; // 9 bit resolution, 93.75 ms
+ else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
+ else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
+ raw = raw << 3; // multiply by 8
+ addLogAdv(LOG_DEBUG, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Family %x, cfg %x, raw %i",Pin, ds18_family, cfg, raw);
+ }
 
+ // Raw is t * 128
+ t = (raw / 128) * 100; // Whole degrees
+ int frac = (raw % 128) * 100 / 128; // Fractional degrees
+ t += t > 0 ? frac : -frac;
 
- Val = (High << 8) + Low; // combine bytes to integer
- negative = (High >= 8); // negative temperature
- if (negative)
- {
- Val = (Val ^ 0xffff) + 1;
- }
- // Temperature is returned in multiples of 1/16 °C
- // we want a simple way to display e.g. xx.yy °C, so just multiply with 100 and we get xxyy 
- // --> the last two digits will be the fractional part (Val%100)
- // --> the whole part of temperature is (int)Val/100
- // so we want 100/16 = 6.25 times the value (the sign to be able to show negative temperatures is in "factor") 
- Tc = (6 * Val) + Val / 4 ;
- t = negative ? -1 : 1 * Tc ;
  dsread=0;
  lastconv=g_secondsElapsed;
- addLogAdv(LOG_INFO, LOG_FEATURE_CFG, "DS1820 - Pin=%i temp=%s%i.%02i \r\n",Pin, negative ? "-" : "+", (int)Tc/100 , (int)Tc%100);
- addLogAdv(LOG_INFO, LOG_FEATURE_CFG, "DS1820 - High=%i Low=%i Val=%i Tc=%i -- Read CRC=%x - calculated:%x \r\n",High, Low, Val,Tc,scratchpad[8],crc);
+ CHANNEL_Set(g_cfg.pins.channels[Pin], t, CHANNEL_SET_FLAG_SILENT);
+ addLogAdv(LOG_INFO, LOG_FEATURE_CFG, "DS1820 - Pin=%i temp=%i.%02i \r\n", Pin, (int)t/100 , (int)t%100);
  }
  }
- else if (g_secondsElapsed % 15 == 0) { // every 15 seconds
-  // ask for "conversion" 
-
- if (OWReset(Pin) == 0){
+ else { 
+ if (OWReset(Pin) == 0) {
+ if (g_secondsElapsed % 15 != 0) return; // only log every 15 seconds
+  
  addLogAdv(LOG_ERROR, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Reset failed",Pin);
 
  // if device is not found, maybe "usleep" is not working as expected
@@ -459,6 +562,15 @@ void DS1820_OnEverySecond() {
 
  } 
  else {
+ if (ds18_family == 0) {
+ int discovered = DS1820_DiscoverFamily();
+ if (!discovered) {
+ addLogAdv(LOG_ERROR, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Family not discovered",Pin);
+ return;
+ }
+ addLogAdv(LOG_INFO, LOG_FEATURE_CFG, "DS1820 - Pin=%i -- Family discovered %x",Pin, ds18_family);
+ }
+
  OWWriteByte(Pin,0xCC);
  OWWriteByte(Pin,0x44);
  addLogAdv(LOG_INFO, LOG_FEATURE_CFG, "DS1820 - asked for conversion - Pin %i",Pin);