diff --git a/display.c b/display.c
--- a/display.c
+++ b/display.c
@@ -24,6 +24,7 @@ static uint8_t sw_right_last = 0;
 // States
 static uint8_t trigger_drawsetpoint = 1;
 static int16_t last_temp = 21245;
+static int16_t last_temp_frac = 21245;
 static int16_t last_state = STATE_IDLE;
 static uint8_t goto_mode = MODE_HEAT;
 static uint8_t reset_mode = RESET_REBOOT;
@@ -36,8 +37,9 @@ void display_process(therm_settings_t* s
     uint8_t state_changed = status->state != last_state;
     last_state = status->state;
     
-    uint8_t temp_changed = status->temp != last_temp;
+    uint8_t temp_changed = status->temp != last_temp || status->temp_frac != last_temp_frac;
     last_temp = status->temp;
+    last_temp_frac = status->temp_frac;
 
     uint8_t sw_btn = !HAL_GPIO_ReadPin(SW_BTN);
     uint8_t sw_up = !HAL_GPIO_ReadPin(SW_UP);
@@ -540,12 +542,13 @@ void display_process(therm_settings_t* s
 
 
 static int32_t temp_last = 43002;
+static int32_t temp_frac_last = 43002;
 static int32_t setpoint_last = 10023;
 
 // Draw current setpoint on display
 static void draw_setpoint(therm_status_t* status) {
     // FIXME: need to do this when switching modes too
-    if(status->temp != temp_last || trigger_drawsetpoint) { 
+    if(status->temp != temp_last || status->temp_frac != temp_frac_last || trigger_drawsetpoint) {
         char tempstr[3];
         itoa_fp(status->temp, status->temp_frac, tempstr);
         ssd1306_drawstringbig("      ", 3, 0);
@@ -565,6 +568,7 @@ static void draw_setpoint(therm_status_t
     trigger_drawsetpoint = 0;
     setpoint_last = status->setpoint;
     temp_last = status->temp;
+    temp_frac_last = status->temp_frac;
 }
 
 void display_startup_screen() {
diff --git a/max31865.c b/max31865.c
--- a/max31865.c
+++ b/max31865.c
@@ -107,15 +107,15 @@ void max31865_readtemp(SPI_HandleTypeDef
 
         	//convert adc to resistance
         	//Rrtd = adc / range * Rref
-        	status->temp = adc_count * 9830 * 10;
-        	status->temp /= 32768;
+        	status->temp = (int32_t) adc_count * 48600L;
+        	status->temp /= 32768L;
         	//resistance to temp
         	//(x - in1) * (cal2 - cal1) / (in2 - in1) + cal1
-        	status->temp = ((status->temp * 100) - 100000) * (39200 - 3200) / (175860 - 100000) + 3200;
+        	status->temp = ((status->temp) - 10000L) * (39200L - 3200L) / (17586L - 10000L) + 3200L;
         	//grab the fraction
-        	status->temp_frac = (status->temp / 10) % 10;
+        	status->temp_frac = (status->temp / 10) % 10L;
         	//scale back to degrees
-        	status->temp = status->temp / 100;
+        	status->temp = status->temp / 100L;
         	//add in the offset
             status->temp += set->val.temp_offset;
         }
@@ -127,15 +127,15 @@ void max31865_readtemp(SPI_HandleTypeDef
 
         	//convert adc to resistance
         	//Rrtd = adc / range * Rref
-        	status->temp = adc_count * 9830 * 10;
-        	status->temp /= 32768;
+        	status->temp = (int32_t) adc_count * 48600L;
+        	status->temp /= 32768L;
         	//resistance to temp
         	//(x - in1) * (cal2 - cal1) / (in2 - in1) + cal1
-        	status->temp = ((status->temp * 10) - 10000) * (20000 - 0) / (17586 - 10000) + 0;
+        	status->temp = (((status->temp) - 10000L) * (20000L- 0L)) / (17586L - 10000L) + 0L;
         	//grab the fraction
-        	status->temp_frac = (status->temp / 10) % 10;
+        	status->temp_frac = (status->temp / 10) % 100L;
         	//scale back to degrees
-        	status->temp = status->temp / 100;
+        	status->temp = status->temp / 100L;
         	//add in the offset
             status->temp += set->val.temp_offset;
         }
diff --git a/system/stringhelpers.c b/system/stringhelpers.c
--- a/system/stringhelpers.c
+++ b/system/stringhelpers.c
@@ -1,8 +1,9 @@
 #include <inttypes.h>
 
+char const digit[] = "0123456789";
+
 char* zitoa(int16_t i, char b[]){
 
-    char const digit[] = "0123456789";
     char* p = b;
     if(i<0){
         *p++ = '-';
@@ -22,7 +23,6 @@ char* zitoa(int16_t i, char b[]){
 }
 
 char* itoa_fp(int16_t i, uint8_t frac, char b[]){
-    char const digit[] = "0123456789";
 
     // set p to beginning of char array
     char* p = b;