diff --git a/analog-stm32.c b/analog-stm32.c
index 959e204..897d64c 100644
--- a/analog-stm32.c
+++ b/analog-stm32.c
@@ -78,7 +78,7 @@ void init_analog() {
   // subt line is to keep compiler happy
   #define DEFINE_TEMP_SENSOR(name, type, pin, additional) \
   if (NUM_TEMP_SENSORS) { \
-    uint8_t subt = (pin ## _ADC >= 10) ? 10 : 0; \
+    uint32_t subt = (pin ## _ADC >= 10) ? 10 : 0; \
     if (pin ## _ADC >= 10) { \
       ADC1->SMPR1 |= (uint32_t)0x06 << (3 * ((pin ## _ADC) - subt)); \
     } else { \
@@ -186,8 +186,8 @@ uint16_t analog_read(uint8_t index) {
   if (NUM_TEMP_SENSORS > 0) {
     uint16_t r = 0;
     uint16_t temp;
-    uint16_t max_temp = 0;
-    uint16_t min_temp = 0xffff;
+    uint32_t max_temp = 0;
+    uint32_t min_temp = UINT32_MAX;
 
     for (uint8_t i = 0; i < OVERSAMPLE; i++) {
       temp = adc_buffer[i][index];
diff --git a/clock.c b/clock.c
index 01a8ab1..0af23fe 100644
--- a/clock.c
+++ b/clock.c
@@ -30,16 +30,16 @@
   Every time our clock fires we increment this,
   so we know when 10ms/250ms/1s has elapsed.
 */
-static uint8_t clock_counter_10ms = 0;
-static uint8_t clock_counter_250ms = 0;
-static uint8_t clock_counter_1s = 0;
+static uint_fast8_t clock_counter_10ms = 0;
+static uint_fast8_t clock_counter_250ms = 0;
+static uint_fast8_t clock_counter_1s = 0;
 
 /**
   Flags to tell clock() when above have elapsed.
 */
-static volatile uint8_t clock_flag_10ms = 0;
-static volatile uint8_t clock_flag_250ms = 0;
-static volatile uint8_t clock_flag_1s = 0;
+static volatile uint_fast8_t clock_flag_10ms = 0;
+static volatile uint_fast8_t clock_flag_250ms = 0;
+static volatile uint_fast8_t clock_flag_1s = 0;
 
 
 /** Advance our clock by a tick.
diff --git a/dda_queue.c b/dda_queue.c
index 0ddd35c..d77efb4 100644
--- a/dda_queue.c
+++ b/dda_queue.c
@@ -21,11 +21,11 @@
   is used both in and out of interrupts, but is only written outside of
   interrupts.
 */
-static uint8_t mb_head = 0;
+static uint_fast8_t mb_head = 0;
 
 /// movebuffer tail pointer. Points to the currently executing move
 /// this variable is read/written both in and out of interrupts.
-uint8_t	mb_tail = 0;
+uint_fast8_t	mb_tail = 0;
 
 /// move buffer.
 /// holds move queue
@@ -46,7 +46,7 @@ DDA *mb_tail_dda;
 #define MB_NEXT(x) ((x) < MOVEBUFFER_SIZE - 1 ? (x) + 1 : 0)
 
 /// check if the queue is completely full
-uint8_t queue_full() {
+uint_fast8_t queue_full() {
 	MEMORY_BARRIER();
   return MB_NEXT(mb_head) == mb_tail;
 }
@@ -87,7 +87,7 @@ void enqueue_home(TARGET *t, uint8_t endstop_check, uint8_t endstop_stop_cond) {
 	while (queue_full())
 		delay_us(100);
 
-  uint8_t h = MB_NEXT(mb_head);
+  uint_fast8_t h = MB_NEXT(mb_head);
 
 	DDA* new_movebuffer = &(movebuffer[h]);
 
diff --git a/dda_queue.h b/dda_queue.h
index 888124b..914f0ce 100644
--- a/dda_queue.h
+++ b/dda_queue.h
@@ -11,7 +11,7 @@
 */
 
 // this is the ringbuffer that holds the current and pending moves.
-extern uint8_t mb_tail;
+extern uint_fast8_t mb_tail;
 extern DDA movebuffer[MOVEBUFFER_SIZE];
 extern DDA *mb_tail_dda;
 
@@ -21,7 +21,7 @@ extern DDA *mb_tail_dda;
 */
 
 // queue status methods
-uint8_t queue_full(void);
+uint_fast8_t queue_full(void);
 
 // take one step
 void queue_step(void);
diff --git a/temp.c b/temp.c
index 1784c91..37ad925 100644
--- a/temp.c
+++ b/temp.c
@@ -75,12 +75,12 @@ static const temp_sensor_definition_t temp_sensors[NUM_TEMP_SENSORS] =
 
 /// this struct holds the runtime sensor data- read temperatures, targets, etc
 static struct {
-	uint16_t					last_read_temp; ///< last received reading
-	uint16_t					target_temp;		///< manipulate attached heater to attempt to achieve this value
+  uint_fast16_t         last_read_temp; ///< last received reading
+  uint_fast16_t         target_temp;    ///< manipulate attached heater to attempt to achieve this value
 
-	uint16_t					temp_residency; ///< how long have we been close to target temperature in temp ticks?
+  uint_fast16_t         temp_residency; ///< how long have we been close to target temperature in temp ticks?
 
-  uint8_t  active;          ///< State machine tracker for readers that need it.
+  uint_fast8_t  active;          ///< State machine tracker for readers that need it.
 } temp_sensors_runtime[NUM_TEMP_SENSORS];
 
 /** \def TEMP_EWMA