From 3ea18e74da1cc84f09c64ce61f2b5f1ee123fb96 Mon Sep 17 00:00:00 2001
From: sheinz <shein@bk.ru>
Date: Fri, 25 Nov 2016 21:42:50 +0200
Subject: [PATCH] ds18b20 fix for temperature below zero

---
 extras/ds18b20/ds18b20.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/extras/ds18b20/ds18b20.c b/extras/ds18b20/ds18b20.c
index 36449d7..e62011d 100644
--- a/extras/ds18b20/ds18b20.c
+++ b/extras/ds18b20/ds18b20.c
@@ -33,7 +33,7 @@ uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
     uint8_t sensor_id = 0;
 
     onewire_search_start(&search);
-    
+
     while ((addr = onewire_search_next(&search, pin)) != ONEWIRE_NONE) {
         uint8_t crc = onewire_crc8((uint8_t *)&addr, 7);
         if (crc != (addr >> 56)){
@@ -44,10 +44,10 @@ uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
         onewire_reset(pin);
         onewire_select(pin, addr);
         onewire_write(pin, DS18B20_CONVERT_T);
-        
+
         onewire_power(pin);
         vTaskDelay(750 / portTICK_PERIOD_MS);
-        
+
         onewire_reset(pin);
         onewire_select(pin, addr);
         onewire_write(pin, DS18B20_READ_SCRATCHPAD);
@@ -57,7 +57,7 @@ uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
         for (int k=0;k<9;k++){
             get[k]=onewire_read(pin);
         }
-        
+
         //debug("\n ScratchPAD DATA = %X %X %X %X %X %X %X %X %X\n",get[8],get[7],get[6],get[5],get[4],get[3],get[2],get[1],get[0]);
         crc = onewire_crc8(get, 8);
 
@@ -69,7 +69,7 @@ uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
         uint8_t temp_msb = get[1]; // Sign byte + lsbit
         uint8_t temp_lsb = get[0]; // Temp data plus lsb
         uint16_t temp = temp_msb << 8 | temp_lsb;
-        
+
         float temperature;
 
         temperature = (temp * 625.0)/10000;
@@ -82,7 +82,7 @@ uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
 }
 
 float ds18b20_read_single(uint8_t pin) {
-  
+
     onewire_reset(pin);
     onewire_skip_rom(pin);
     onewire_write(pin, DS18B20_CONVERT_T);
@@ -93,13 +93,13 @@ float ds18b20_read_single(uint8_t pin) {
     onewire_reset(pin);
     onewire_skip_rom(pin);
     onewire_write(pin, DS18B20_READ_SCRATCHPAD);
-    
+
     uint8_t get[10];
 
     for (int k=0;k<9;k++){
         get[k]=onewire_read(pin);
     }
-    
+
     //debug("\n ScratchPAD DATA = %X %X %X %X %X %X %X %X %X\n",get[8],get[7],get[6],get[5],get[4],get[3],get[2],get[1],get[0]);
     uint8_t crc = onewire_crc8(get, 8);
 
@@ -110,9 +110,9 @@ float ds18b20_read_single(uint8_t pin) {
 
     uint8_t temp_msb = get[1]; // Sign byte + lsbit
     uint8_t temp_lsb = get[0]; // Temp data plus lsb
-    
+
     uint16_t temp = temp_msb << 8 | temp_lsb;
-    
+
     float temperature;
 
     temperature = (temp * 625.0)/10000;
@@ -157,7 +157,7 @@ bool ds18b20_read_scratchpad(int pin, ds18b20_addr_t addr, uint8_t *buffer) {
         onewire_select(pin, addr);
     }
     onewire_write(pin, DS18B20_READ_SCRATCHPAD);
-    
+
     for (int i = 0; i < 8; i++) {
         buffer[i] = onewire_read(pin);
     }
@@ -174,7 +174,7 @@ bool ds18b20_read_scratchpad(int pin, ds18b20_addr_t addr, uint8_t *buffer) {
 
 float ds18b20_read_temperature(int pin, ds18b20_addr_t addr) {
     uint8_t scratchpad[8];
-    int temp;
+    int16_t temp;
 
     if (!ds18b20_read_scratchpad(pin, addr, scratchpad)) {
         return NAN;