Freq count t4 branch

FreqCount.cpp

@@ -26,14 +26,11 @@
 #include "FreqCount.h"
 #include "util/FreqCountTimers.h"
 
+#if(!defined(__IMXRT1062__))
 static uint16_t count_msw;
-static uint32_t count_prev;
-static volatile uint32_t count_output;
-static volatile uint8_t count_ready;
 static uint16_t gate_length;
 static uint16_t gate_index;
 
-
 void FreqCountClass::begin(uint16_t msec)
 {
 	if (msec < 1) return;
@@ -113,6 +110,28 @@ ISR(TIMER_ISR_VECTOR)
 	}
 }
 
+#else
+void FreqCountClass::begin(uint32_t msec)
+{
+  counter_init();
+  timer_init(msec);  // us
+  counter_start();
+}
+
+uint8_t FreqCountClass::available(void)
+{
+	return count_ready;
+}
+
+uint32_t FreqCountClass::read(void)
+{
+  if (count_ready) {
+    count_ready = 0;
+  }
+    return count_output;
+}
+
+#endif
 
 FreqCountClass FreqCount;
 

FreqCount.h

@@ -5,7 +5,11 @@
 
 class FreqCountClass {
 public:
-	static void begin(uint16_t msec);
+	#if(!defined(__IMXRT1062__))
+		static void begin(uint16_t msec);
+	#else
+		static void begin(uint32_t msec);
+	#endif
 	static uint8_t available(void);
 	static uint32_t read(void);
 	static void end(void);

examples/Serial_Output_T4/Serial_Output_T4.ino

@@ -0,0 +1,28 @@
+/* FreqCount - Example with serial output
+ * http://www.pjrc.com/teensy/td_libs_FreqCount.html
+ *
+ * This example code is in the public domain.
+ *
+ * For the Teensy 4.0 pin 14 is used to measure the freq
+ * FreqCount.begin time is in microseconds vs milliseconds
+ * for other boards.
+ */
+#include <FreqCount.h>
+
+void setup() {
+  Serial.begin(57600);
+
+  delay(2000);
+  analogWriteFrequency(11, 123456);  // test jumper 11 to 25
+  analogWrite(11, 128);
+
+  FreqCount.begin(1000000);  //Time in microseconds
+}
+
+void loop() {
+  if (FreqCount.available()) {
+    unsigned long count = FreqCount.read();
+    Serial.println(count);
+  }
+}
+

util/FreqCountTimers.h

@@ -26,6 +26,10 @@
 #ifndef FreqCount_timers_h_
 #define FreqCount_timers_h_
 
+static uint32_t count_prev;
+static volatile uint32_t count_output;
+static volatile uint8_t count_ready;
+
 // Arduino Mega
 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
   // #define COUNTER_USE_TIMER1 // T1 is not connected
@@ -34,6 +38,11 @@
   #define COUNTER_USE_TIMER5    // T5 is pin 47
   #define TIMER_USE_TIMER2
 
+//Teensy 4.0
+#elif defined(__IMXRT1062__)
+	#define COUNTER_USE_GPT
+    #define TIMER_USE_INTERVALTIMER_T4
+
 // Teensy 3.0 & 3.1 & LC
 #elif defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MKL26Z64__) || defined(__MK64FX512__) || defined(__MK66FX1M0__)
   #define COUNTER_USE_LPTMR     // LPTMR is pin 13  (has LED connected)
@@ -109,6 +118,42 @@ static inline void counter_overflow_reset(void)
 }
 
 
+#elif defined(COUNTER_USE_GPT)
+static inline void counter_init(void)
+{
+  CCM_CCGR0 |= CCM_CCGR0_GPT2_BUS(CCM_CCGR_ON) ;  // enable GPT2 module
+  GPT2_CR = 0;
+  GPT2_SR = 0x3F; // clear all prior status
+  GPT2_CR =  GPT_CR_CLKSRC(3);// | GPT_CR_FRR ;// 3 external clock
+  IOMUXC_SW_MUX_CTL_PAD_GPIO_AD_B1_02 = 0x08;  //uses pin 14
+  IOMUXC_GPT2_IPP_IND_CLKIN_SELECT_INPUT = 0x01;
+}
+
+static inline void counter_start(void)
+{
+  GPT2_CR |= GPT_CR_EN; // enable
+}
+
+static inline void counter_shutdown(void)
+{
+  GPT2_CR = 0;
+}
+
+static inline uint32_t counter_read(void)  // was uint16_t in FreqCount?
+{
+  return GPT2_CNT;
+}
+
+static inline uint8_t counter_overflow(void)
+{
+  return GPT2_SR & GPT_SR_ROV;
+}
+
+static inline void counter_overflow_reset(void)
+{
+  GPT2_SR |= GPT_SR_ROV;
+}
+
 
 
 #elif defined(COUNTER_USE_TIMER1) // 16 bit Timer 1 on Atmel AVR
@@ -296,7 +341,7 @@ static inline void counter_overflow_reset(void)
 #if defined(TIMER_USE_INTERVALTIMER) // Teensyduino IntervalTimer
 
 static IntervalTimer itimer;
-static void timer_interrupt(void);
+static void timer_callback(void);
 
 static inline uint16_t timer_init(uint16_t msec)
 {
@@ -308,7 +353,7 @@ static inline void timer_start(void)
 	// IntervalTimer is capable of longer intervals, but
 	// LPTMR can overflow.  Limiting to 1 ms allows counting
 	// up to 65.535 MHz... LPTMR on Teensy 3.1 can do 65 MHz!
-	itimer.begin(timer_interrupt, 1000);
+	itimer.begin(timer_callback, 1000000);
 }
 
 static inline void timer_shutdown(void)
@@ -322,7 +367,21 @@ static inline void timer_shutdown(void)
 #endif
 #define ISR(name) void name (void)
 
+#elif defined(TIMER_USE_INTERVALTIMER_T4)
+static IntervalTimer itimer;
+
+void timer_callback() {
+  uint32_t count = counter_read();
 
+  //track rollover ?
+  count_output = count - count_prev;
+  count_prev = count;
+  count_ready = 1;
+}
+
+void timer_init(uint32_t msec){
+	itimer.begin(timer_callback, msec);
+}
 
 
 #elif defined(TIMER_USE_TIMER2) // 8 bit Timer 2 on Atmel AVR