diff --git a/display.c b/display.c
--- a/display.c
+++ b/display.c
@@ -335,7 +335,7 @@ void display_process(therm_settings_t* s
                 status->state = STATE_IDLE;
             }
             else {
-                user_input_signed((int16_t*)(&set->val.temp_offset));
+                user_input_signed(&set->val.temp_offset);
             }
 
             // Event Handler
@@ -354,7 +354,7 @@ void display_process(therm_settings_t* s
             draw_setpoint(status);
 
             status->pid_enabled = 1;
-	    status->setpoint = set->val.setpoint_brew;
+            status->setpoint = set->val.setpoint_brew;
 
             // Button handler
             if(SW_BTN_PRESSED) {
@@ -380,7 +380,7 @@ void display_process(therm_settings_t* s
             //ssd1306_drawlogo();
             draw_setpoint(status);
             status->pid_enabled = 1;
-	    status->setpoint = set->val.setpoint_brew;
+            status->setpoint = set->val.setpoint_brew;
 
             // Button handler
             if(SW_BTN_PRESSED) {
@@ -567,4 +567,10 @@ static void draw_setpoint(therm_status_t
     temp_last = status->temp;
 }
 
+void display_startup_screen() {
+    ssd1306_clearscreen();
+    ssd1306_drawstring("therm v0.2", 1, 40);
+    ssd1306_drawstring("protofusion.org/therm", 3, 0);
+}
+
 // vim:softtabstop=4 shiftwidth=4 expandtab 
diff --git a/display.h b/display.h
--- a/display.h
+++ b/display.h
@@ -15,6 +15,7 @@
 #include "max31865.h"
 #endif
 
+void display_startup_screen();
 void display_process(therm_settings_t* set, therm_status_t* status);
 
 #endif
diff --git a/gpio.c b/gpio.c
--- a/gpio.c
+++ b/gpio.c
@@ -21,17 +21,19 @@ void user_input(uint16_t* to_modify)
 
 
 // Increment/decrement signed variable with up/down buttons
-void user_input_signed(int16_t* to_modify)
+void user_input_signed(int32_t* to_modify)
 {
-    // TODO: Bounds check on int16_t
+	//fixme: need to cast to 16/32 bits correctly
     if(CHANGE_ELAPSED) {
         if(!HAL_GPIO_ReadPin(SW_UP) ) {
             CHANGE_RESET;
-            (*to_modify)++;
+            if (*to_modify < 32768)
+            	(*to_modify)++;
         }
         else if(!HAL_GPIO_ReadPin(SW_DOWN)) {
             CHANGE_RESET;
-            (*to_modify)--;
+            if (*to_modify >= -32768)
+            	(*to_modify)--;
         }
     }
 }
diff --git a/gpio.h b/gpio.h
--- a/gpio.h
+++ b/gpio.h
@@ -12,7 +12,7 @@
 
 
 void user_input(uint16_t* to_modify);
-void user_input_signed(int16_t* to_modify);
+void user_input_signed(int32_t* to_modify);
 void gpio_init(void);
 
 #endif
diff --git a/main.c b/main.c
--- a/main.c
+++ b/main.c
@@ -5,11 +5,10 @@
 #include "pid.h"
 #include "states.h"
 #include "ssd1306.h"
-#ifdef MAX31855_TC_SENSOR
-#include "max31855.h"
-#endif
 #ifdef MAX31865_RTD_SENSOR
 #include "max31865.h"
+#else
+#include "max31855.h"
 #endif
 #include "gpio.h"
 #include "spi.h"
@@ -22,6 +21,7 @@
 
 therm_settings_t set;
 therm_status_t status;
+pid_state_t pid_state;
 
 int main(void)
 {
@@ -53,13 +53,16 @@ int main(void)
     // Init SPI busses
     spi_init();
     
+    // Init RTD chip
     #ifdef MAX31865_RTD_SENSOR
     max31865_config(spi_get());
     #endif
 
     // Init OLED over SPI
     ssd1306_init();
-    ssd1306_clearscreen();
+
+    // Startup screen
+    display_startup_screen();
 
     // Default status
     status.temp = 0;
@@ -69,20 +72,16 @@ int main(void)
     status.setpoint = 70;
     status.pid_enabled = 0;
 
+    pid_init(&pid_state);
+
     // Go to brew instead of idle if configured thusly
     if(set.val.boottobrew)
       status.state = STATE_PREHEAT; 
 
-    // Startup screen 
-    ssd1306_drawstring("therm v0.2", 1, 40);
-    ssd1306_drawstring("protofusion.org/therm", 3, 0);
-
-    HAL_Delay(1000);
-
     // Restore settings from flash memory
     flash_restore(&set);
 
-    HAL_Delay(1000);
+    HAL_Delay(2000);
     ssd1306_clearscreen();
 
     // Soft timers
@@ -104,21 +103,27 @@ int main(void)
 
         if((HAL_GetTick() - last_pid > PID_PERIOD))
         {
-            #ifdef MAX31855_TC_SENSOR
-            max31855_readtemp(spi_get(), &set, &status); // Read MAX31855
-            #endif
 
             #ifdef MAX31865_RTD_SENSOR
             max31865_readtemp(spi_get(), &set, &status);
-            #endif
+			#else
+			max31855_readtemp(spi_get(), &set, &status); // Read MAX31855
+			#endif
 
 
             if(status.pid_enabled) 
             {
                 // Get ssr output for next time
-                int16_t power_percent = pid_update(set.val.k_p, set.val.k_i, set.val.k_d, status.temp, status.temp_frac, status.setpoint, &set, &status);
+                int16_t power_percent = pid_update(&set, &status, &pid_state);
                 //power-percent is 0-1000?
                 ssr_output = power_percent; //(((uint32_t)SSR_PERIOD * (uint32_t)10 * (uint32_t)100) * power_percent) / (uint32_t)1000000;
+
+
+            	// put ssr output on display
+                ssd1306_drawstring("      ", 0, 90); //fixme: this is bad, but I can't get the old digits to clear otherwise
+                char tempstr[6];
+                itoa(ssr_output, tempstr, 10);
+                ssd1306_drawstring(tempstr, 0, 90);
             }
             else 
             {
@@ -138,12 +143,10 @@ int main(void)
         // Every 200ms, set the SSR on unless output is 0
         if(HAL_GetTick() - last_ssr_on > SSR_PERIOD)
         {
+
             // Only support heating (ssr_output > 0) right now
             if(ssr_output > 0) 
             {
-                char tempstr[6];
-                itoa(ssr_output, tempstr, 10);
-                ssd1306_drawstring(tempstr, 0, 90);
 
                 HAL_GPIO_WritePin(SSR_PIN, 1);
                 HAL_GPIO_WritePin(LED_POWER, 1);
@@ -157,7 +160,7 @@ int main(void)
             
         }
         
-        // Transmit temperature over USB-CDC on a regulat basis
+        // Transmit temperature over USB-CDC on a regular basis
         if(HAL_GetTick() - last_vcp_tx > VCP_TX_FREQ)
         {
             // Print temp to cdc
diff --git a/max31865.c b/max31865.c
--- a/max31865.c
+++ b/max31865.c
@@ -53,14 +53,8 @@ void max31865_clear_errors(SPI_HandleTyp
 // Grab temperature reading from MAX31865
 void max31865_readtemp(SPI_HandleTypeDef* hspi1, therm_settings_t* set, therm_status_t* status)
 {
-    ///////////////////////////////////
-    // This is duplicated from MAX31855, update for MAX31865 registers/etc
-    /////////////////////////////////// 
 
-    // TODO: Set configuration register based on params in config.h (2-wire, 4-wire, etc RTD). This is register 0x00.
-        // 2-wire RTC or 2-wire (duh) NTC thermistor will be the only options
-        // Need option for resistance of RTD
-        // These options should be stored in the set structure and should be menu-selectable
+    // TODO: Set RTD ref resistance in set struct
 
     // Assert CS
     HAL_GPIO_WritePin(MAX_CS, 0);
diff --git a/pid.c b/pid.c
--- a/pid.c
+++ b/pid.c
@@ -1,22 +1,24 @@
-#include "stm32f0xx_hal.h"
-#include "states.h"
+#include "pid.h"
 
 // PID implementation
-// TODO: Make struct that has the last_temp and i_state in it, pass by ref. Make struct that has other input values maybe.
-static int16_t last_pid_temp = 0;
-static uint8_t last_pid_temp_frac = 0;
-static int32_t i_state = 0;
 
-int16_t pid_update(uint16_t k_p, uint16_t k_i, uint16_t k_d, int16_t temp, uint8_t temp_frac, int16_t setpoint, therm_settings_t* set, therm_status_t* status) 
+void pid_init(pid_state_t* state)
+{
+	state->i_state = 0;
+	state->last_pid_temp = 0;
+	state->last_pid_temp_frac = 0;
+}
+
+int16_t pid_update(therm_settings_t* set, therm_status_t* status, pid_state_t *state)
 {
   // Calculate instantaneous error
-  int16_t error = setpoint - temp; // TODO: Use fixed point fraction
+  int16_t error = status->setpoint - status->temp; // TODO: Use fixed point fraction
 
   // Proportional component
-  int32_t p_term = k_p * error;
+  int32_t p_term = set->val.k_p * error;
 
   // Error accumulator (integrator)
-  i_state += error;
+  state->i_state += error;
 
   // to prevent the iTerm getting huge from lots of 
   //  error, we use a "windup guard" 
@@ -24,22 +26,22 @@ int16_t pid_update(uint16_t k_p, uint16_
   // it cant help be cold despite its best efforts)
   // not necessary, but this makes windup guard values 
   // relative to the current iGain
-  int32_t windup_guard_res = set->val.windup_guard / k_i;  
+  int32_t windup_guard_res = set->val.windup_guard / set->val.k_i;
 
   // Calculate integral term with windup guard 
-  if (i_state > windup_guard_res) 
-    i_state = windup_guard_res;
-  else if (i_state < -windup_guard_res) 
-    i_state = -windup_guard_res;
+  if (state->i_state > windup_guard_res)
+	  state->i_state = windup_guard_res;
+  else if (state->i_state < -windup_guard_res)
+	  state->i_state = -windup_guard_res;
 
-  int32_t i_term = k_i * i_state;
+  int32_t i_term = set->val.k_i * state->i_state;
 
   // Calculate differential term (slope since last iteration)
-  int32_t d_term = (k_d * (status->temp - last_pid_temp));
+  int32_t d_term = (set->val.k_d * (status->temp - state->last_pid_temp));
 
   // Save temperature for next iteration
-  last_pid_temp = status->temp;
-  last_pid_temp_frac = status->temp_frac;
+  state->last_pid_temp = status->temp;
+  state->last_pid_temp_frac = status->temp_frac;
 
   int16_t result = p_term + i_term - d_term;
 
diff --git a/pid.h b/pid.h
--- a/pid.h
+++ b/pid.h
@@ -1,8 +1,16 @@
 #ifndef PIDS_H
 #define PIDS_H
 
+#include "stm32f0xx_hal.h"
 #include "states.h"
 
-int16_t pid_update(uint16_t k_p, uint16_t k_i, uint16_t k_d, int16_t temp, uint8_t temp_frac, int16_t setpoint, therm_settings_t* set, therm_status_t* status);
+typedef struct {
+	int16_t last_pid_temp;
+	uint8_t last_pid_temp_frac;
+	int32_t i_state;
+} pid_state_t;
+
+void pid_init(pid_state_t* state);
+int16_t pid_update(therm_settings_t* set, therm_status_t* status, pid_state_t* state);
 
 #endif