diff --git a/display.c b/display.c
--- a/display.c
+++ b/display.c
@@ -8,14 +8,14 @@
 #include "flash.h"
 #include "gpio.h"
 
-uint8_t goto_mode = 2;
+static uint8_t goto_mode = 2;
 
 // State machine
-uint8_t sw_btn_last = 0;
-uint8_t sw_up_last = 0;
-uint8_t sw_down_last = 0;
-uint8_t sw_left_last = 0;
-uint8_t sw_right_last = 0;
+static uint8_t sw_btn_last = 0;
+static uint8_t sw_up_last = 0;
+static uint8_t sw_down_last = 0;
+static uint8_t sw_left_last = 0;
+static uint8_t sw_right_last = 0;
 
 #define SW_BTN_PRESSED (sw_btn_last == 0 && sw_btn == 1) // rising edge on buttonpress
 #define SW_UP_PRESSED (sw_up_last == 0 && sw_up == 1)
@@ -24,9 +24,9 @@ uint8_t sw_right_last = 0;
 #define SW_RIGHT_PRESSED (sw_right_last == 0 && sw_right == 1)
 
 
-uint8_t trigger_drawsetpoint = 1;
+static uint8_t trigger_drawsetpoint = 1;
 
-int16_t last_temp = 21245;
+static int16_t last_temp = 21245;
 
 void display_process(therm_settings_t* set, therm_status_t* status)
 {
@@ -505,8 +505,8 @@ void display_process(therm_settings_t* s
 }
 
 
-int32_t temp_last = 43002;
-int32_t setpoint_last = 10023;
+static int32_t temp_last = 43002;
+static int32_t setpoint_last = 10023;
 void draw_setpoint(therm_status_t* status) {
     // FIXME: need to do this when switching modes too
     if(status->temp != temp_last || trigger_drawsetpoint) {