diff --git a/Tlc5940.cpp b/Tlc5940.cpp
index 12a3b44..179a933 100644
--- a/Tlc5940.cpp
+++ b/Tlc5940.cpp
@@ -65,8 +65,18 @@ static inline void Tlc5940_interrupt(void)
 }
 
 #if defined(__AVR__)
-ISR(TIMER1_OVF_vect) { Tlc5940_interrupt(); }
+ISR(TIMER1_OVF_vect)
+{
+    Tlc5940_interrupt();
+}
+
 #elif defined(__arm__) && defined(TEENSYDUINO)
+void ftm1_isr(void)
+{
+    uint32_t sc = FTM1_SC;
+    if (sc & 0x80) FTM1_SC = sc & 0x7F;
+    Tlc5940_interrupt();
+}
 
 #endif
 
@@ -152,24 +162,33 @@ void Tlc5940::init(uint16_t initialValue)
     TCCR1B |= _BV(CS10);      // no prescale, (start pwm output)
 
 #elif defined(__arm__) && defined(TEENSYDUINO)
-	SIM_SCGC4 |= SIM_SCGC4_CMT;
-	CMT_MSC = 0;
-	CMT_PPS = 0;
-	CMT_CGH1 = TLC_TIMER_TEENSY3_NORMAL_CGH1;
-	CMT_CGL1 = TLC_TIMER_TEENSY3_NORMAL_CGL1;
-	CMT_CMD1 = 1;
-	CMT_CMD2 = 0;
-	CMT_CMD3 = 0;
-	CMT_CMD4 = 0;
-	CMT_OC = 0x60;
-	CMT_MSC = 0x01;
-	CORE_PIN5_CONFIG = PORT_PCR_MUX(2)|PORT_PCR_DSE|PORT_PCR_SRE;
+    clear_pin(XLAT_DDR, XLAT_PIN);
+    SIM_SCGC4 |= SIM_SCGC4_CMT;
+    CMT_MSC = 0;
+    CMT_PPS = 0;
+    CMT_CGH1 = TLC_TIMER_TEENSY3_NORMAL_CGH1;
+    CMT_CGL1 = TLC_TIMER_TEENSY3_NORMAL_CGL1;
+    CMT_CMD1 = 1;
+    CMT_CMD2 = 0;
+    CMT_CMD3 = 0;
+    CMT_CMD4 = 0;
+    CMT_OC = 0x60;
+    CMT_MSC = 0x01;
+    CORE_PIN5_CONFIG = PORT_PCR_MUX(2)|PORT_PCR_DSE|PORT_PCR_SRE;
+    FTM1_SC = 0;
+    FTM1_MOD = TLC_TIMER_TEENSY3_NORMAL_MOD;
+    FTM1_CNT = 0;
+    FTM1_C0SC = 0x24;
+    FTM1_C1SC = 0x24;
+    FTM1_C0V = TLC_TIMER_TEENSY3_NORMAL_MOD - TLC_TIMER_TEENSY3_NORMAL_CV;
+    FTM1_C1V = TLC_TIMER_TEENSY3_NORMAL_MOD - TLC_TIMER_TEENSY3_NORMAL_CV - 1;
+    FTM1_SC = FTM_SC_CLKS(1) | FTM_SC_CPWMS;
+    NVIC_ENABLE_IRQ(IRQ_FTM1);
+    CORE_PIN4_CONFIG = PORT_PCR_MUX(3)|PORT_PCR_DSE|PORT_PCR_SRE;
 #endif
     update();
 }
 
-void cmt_isr(void) { uint8_t tmp = CMT_MSC; tmp = CMT_CMD2; }
-
 /** Clears the grayscale data array, #tlc_GSData, but does not shift in any
     data.  This call should be followed by update() if you are turning off
     all the outputs. */
diff --git a/Tlc5940.h b/Tlc5940.h
index 7e30a30..64f4526 100644
--- a/Tlc5940.h
+++ b/Tlc5940.h
@@ -50,11 +50,10 @@
 #define disable_XLAT_pulses()   TCCR1A = _BV(COM1B1)
 
 #elif defined(__arm__) && defined(TEENSYDUINO)
-
-#define set_XLAT_interrupt()    
-#define clear_XLAT_interrupt()  
-#define enable_XLAT_pulses()    
-#define disable_XLAT_pulses()   
+#define set_XLAT_interrupt()    { uint32_t tmp __attribute__((unused)) = FTM1_SC; FTM1_SC = FTM_SC_CLKS(1) | FTM_SC_CPWMS | FTM_SC_TOIE; }
+#define clear_XLAT_interrupt()  FTM1_SC = FTM_SC_CLKS(1) | FTM_SC_CPWMS
+#define enable_XLAT_pulses()    CORE_PIN3_CONFIG = PORT_PCR_MUX(3)|PORT_PCR_DSE|PORT_PCR_SRE
+#define disable_XLAT_pulses()   CORE_PIN3_CONFIG = PORT_PCR_MUX(1)|PORT_PCR_DSE|PORT_PCR_SRE
 
 #endif
 
diff --git a/pinouts/Teensy_KinetisK20.h b/pinouts/Teensy_KinetisK20.h
index c81f480..eed07e5 100644
--- a/pinouts/Teensy_KinetisK20.h
+++ b/pinouts/Teensy_KinetisK20.h
@@ -37,24 +37,38 @@
 #if F_BUS == 60000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		4
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		11
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		30720
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		4
 #elif F_BUS == 56000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		3
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		11
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		28672
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		3
 #elif F_BUS == 48000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		3
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		9
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		24576
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		3
 #elif F_BUS == 36000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		2
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		7
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		18432
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		2
 #elif F_BUS == 24000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		2
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		4
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		12288
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		2
 #elif F_BUS == 16000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		1
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		3
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		8192
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		1
 #elif F_BUS <= 8000000
   #define TLC_TIMER_TEENSY3_NORMAL_CGH1		1
   #define TLC_TIMER_TEENSY3_NORMAL_CGL1		1
+  #define TLC_TIMER_TEENSY3_NORMAL_MOD		4096
+  #define TLC_TIMER_TEENSY3_NORMAL_CV		1
 #else
 #error "F_BUS must be 60, 56, 48, 36, 24, 16, 8, 4, or 2 MHz"
 #endif
diff --git a/pinouts/pin_functions.h b/pinouts/pin_functions.h
index 5a716a1..52ea0f3 100644
--- a/pinouts/pin_functions.h
+++ b/pinouts/pin_functions.h
@@ -8,13 +8,13 @@
   #define output_pin(ddr, pin)        ddr |= _BV(pin)
   #define pullup_pin(ddr, port, pin)  ddr &= ~_BV(pin); port |= _BV(pin)
 #elif defined(TEENSYDUINO)
-  #define pulse_pin(port, pin)        digitalWriteFast(pin, LOW); digitalWriteFast(pin, HIGH)
+  #define pulse_pin(port, pin)        digitalWriteFast(pin, HIGH); digitalWriteFast(pin, LOW)
   #define set_pin(port, pin)          digitalWriteFast(pin, HIGH)
   #define clear_pin(port, pin)        digitalWriteFast(pin, LOW)
   #define output_pin(ddr, pin)        pinMode(pin, OUTPUT)
   #define pullup_pin(ddr, port, pin)  pinMode(pin, INPUT_PULLUP)
 #else
-  #define pulse_pin(port, pin)        digitalWrite(pin, LOW); digitalWrite(pin, HIGH)
+  #define pulse_pin(port, pin)        digitalWrite(pin, HIGH); digitalWrite(pin, LOW)
   #define set_pin(port, pin)          digitalWrite(pin, HIGH)
   #define clear_pin(port, pin)        digitalWrite(pin, LOW)
   #define output_pin(ddr, pin)        pinMode(pin, OUTPUT)