2 files changed, 12 insertions, 6 deletions
diff --git a/src/temperature.c b/src/temperature.c
index b804fc9..72e4875 100644
--- a/src/temperature.c
+++ b/src/temperature.c
@@ -37,13 +37,17 @@ uint16_t spi_read16(void) {
 
 float temperature_read(void) {
   THERMO_PORT &= ~(1 << THERMO_CS);
-  uint16_t v = spi_read16();
+  uint16_t out = spi_read16();
   THERMO_PORT |= (1 << THERMO_CS);
 
-  // invalid temp
-  if (v & 0x4)
-    return 999.9;
+  // thermocouple open (invalid read) D2 bit
+  if (out & 0b100)
+    return 0.0;
 
-  v >>= 3;
-  return v * 0.25;
+  out >>= 3; // Skip D0,D1,D2
+
+  float temperature = out * THERMO_RESOLUTION;
+  if (temperature > 100)
+    temperature *= 1.05;
+  return temperature;
 }
diff --git a/src/temperature.h b/src/temperature.h
index 31fa92a..c15fe22 100644
--- a/src/temperature.h
+++ b/src/temperature.h
@@ -4,6 +4,8 @@
 #define THERMO_PORT PORTA
 #define THERMO_DDR DDRA
 
+#define THERMO_RESOLUTION 0.25
+
 #define SPI_DELAY_US 10
 
 void temperature_init(void);