diff --git a/fw/HackSpaceCon/src/isr.cpp b/fw/HackSpaceCon/src/isr.cpp
new file mode 100644
index 0000000..896eeba
--- /dev/null
+++ b/fw/HackSpaceCon/src/isr.cpp
@@ -0,0 +1,37 @@
+#include <Arduino.h>
+
+
+extern uint8_t run_rgb_program;
+
+
+// TCB0 general interrupt
+ISR(TCB0_INT_vect)
+{
+    // reset the INTFLAGS - necessary on this series
+    uint8_t intflags = TCB0.INTFLAGS;
+    TCB0.INTFLAGS = intflags;
+
+    // in this program, this interrupt is only used for timing.
+    // we'll now return to executing loop()
+}
+
+// button interrupt
+ISR(PORTA_PORT_vect)
+{
+    // reset the INTFLAGS - necessary on this series
+    uint8_t intflags = PORTA.INTFLAGS;
+    PORTA.INTFLAGS = intflags;
+
+	// was our pin changed?
+    if (intflags & PIN3_bm) {
+		// is the pin low?
+		if (!digitalRead(PIN_PA3)) {
+			// start running a program if one isn't running already
+        	if (!run_rgb_program) run_rgb_program = 1;
+		} else if (run_rgb_program == 2) {
+			// if we're running a program when the button is released (likely),
+			// then skip this interrupt
+			run_rgb_program++;
+		}
+    }
+}
\ No newline at end of file
diff --git a/fw/HackSpaceCon/src/main.cpp b/fw/HackSpaceCon/src/main.cpp
index be526d0..8c61625 100644
--- a/fw/HackSpaceCon/src/main.cpp
+++ b/fw/HackSpaceCon/src/main.cpp
@@ -71,14 +71,14 @@ void idle_cpu()
 	__asm("sleep");
 }
 
-inline void sleep_cpu()
+void sleep_cpu()
 {
 	SLPCTRL.CTRLA = SLPCTRL_SMODE_STDBY_gc | SLPCTRL_SEN_bm;
 	__asm("sleep");
 }
 
 
-
+// mcu init
 void setup() {
 	// configure PA3 as both edge interrupt input for button
 	// note: only PA2 and PA6 support async wakeup and thus we can't check for
@@ -105,6 +105,7 @@ void setup() {
 	sei();
 }
 
+// mcu program loop
 void loop() {
 	switch (run_rgb_program) {
 		case RGB_PROG_INIT: {					// just started running a program
@@ -153,24 +154,3 @@ void loop() {
 		}
 	}
 }
-
-// button interrupt
-ISR(PORTA_PORT_vect)
-{
-    // reset the INTFLAGS - necessary on this series
-    uint8_t intflags = PORTA.INTFLAGS;
-    PORTA.INTFLAGS = intflags;
-
-	// was our pin changed?
-    if (intflags & PIN3_bm) {
-		// is the pin low?
-		if (!digitalRead(PIN_PA3)) {
-			// start running a program if one isn't running already
-        	if (!run_rgb_program) run_rgb_program = 1;
-		} else if (run_rgb_program == 2) {
-			// if we're running a program when the button is released (likely),
-			// then skip this interrupt
-			run_rgb_program++;
-		}
-    }
-}
\ No newline at end of file
diff --git a/fw/HackSpaceCon/src/rgbled.cpp b/fw/HackSpaceCon/src/rgbled.cpp
index 8974901..9920eef 100644
--- a/fw/HackSpaceCon/src/rgbled.cpp
+++ b/fw/HackSpaceCon/src/rgbled.cpp
@@ -37,15 +37,9 @@ void conf_rgb_timer()
     TCB0.CNT = 0;
 }
 
-ISR(TCB0_INT_vect)
-{
-    // reset the INTFLAGS - necessary on this series
-    uint8_t intflags = TCB0.INTFLAGS;
-    TCB0.INTFLAGS = intflags;
 
-    // we don't care why we interrupted.
-    // we'll now return to executing loop()
-}
+// globals for all rgb programs
+uint16_t prog_timeout;
 
 
 // rgb program 0: rainbow puke
@@ -56,7 +50,6 @@ ISR(TCB0_INT_vect)
 #define RAINBOW_VAL         0x40                // value (brightness); keep low enough to keep average current down
 
 uint16_t rainbow_hue = 0;
-uint16_t rainbow_timeout;
 
 uint8_t rgbp_rainbow(uint8_t init)
 {
@@ -66,10 +59,10 @@ uint8_t rgbp_rainbow(uint8_t init)
 
     // set our timer when initializing. otherwise every call is identical
     if (init) {
-        rainbow_timeout = RAINBOW_TIMEOUT;
+        prog_timeout = RAINBOW_TIMEOUT;
     }
 
-    if (--rainbow_timeout) {
+    if (--prog_timeout) {
         // copy stored hue to working hue
         hue = rainbow_hue;