firmware: recalculate SAMPLE_FREQ for accurate frequency output

Firmware/include/sine.h

@@ -4,7 +4,7 @@
 
 // Sampling frequency of the DAC
 // Since the teensy runs on 168MHz and Fastest + LTO, using the DAC sampling frequency (1428571Hz) from the Datasheet kinda falls apart
-#define SAMPLE_FREQ 5316436 
+#define SAMPLE_FREQ 6222000 
 
 //Max Freq with good results achievable with Teensy 3.5 DAC
 #define MAX_ACHIEVABLE_FREQ 1000000

Firmware/include/square.h

@@ -1,7 +1,9 @@
 #pragma once
 
-#define SQUARE_PIN 33
+#define SQUARE_PIN A22 //DAC1
+
 
 void setupSquare();
 void generateSquare(float, int);
+void generateSquareDAC1(float, int);
 

Firmware/include/wave.h

@@ -8,8 +8,8 @@
 #define extr extern
 #endif
 
-#define MAX_VALUE 1024
-#define MAX_VALUE_HALF 512
+#define MAX_VALUE 4096
+#define MAX_VALUE_HALF 2048
 
 //How much time (nanoseconds) is required for an analogWriteDAC0() call
 #define ANALOG_WRITE_TIME_NS 477
@@ -20,6 +20,10 @@
 // Overhead when counting cycles
 #define CYCLE_OVERHEAD 0
 
+
+#define DAC1_SEL 23
+#define DAC0_SEL 22
+
 FASTRUN void startGenerating();
 FASTRUN void stopGenerating();
 FASTRUN void delayCycles(unsigned long);

Firmware/src/main.cpp

@@ -4,11 +4,15 @@
 #include "sine.h"
 
 void setup() {
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, HIGH);
+
+
   setupWaves();
   setupSine();
   setupSquare();
 }
 
 FASTRUN void loop() {
-  generateSine(1000000);
+  generateSine(8150);
 }

Firmware/src/sine.cpp

@@ -30,6 +30,9 @@ typedef int16_t __attribute__((__may_alias__)) aliased_int16_t;
 
 FASTRUN void generateSine(float frequency){
     startGenerating();
+    
+    digitalWriteFast(DAC0_SEL, HIGH);
+    digitalWriteFast(DAC1_SEL, LOW);  
 
     // Phase accumulator
     float phase = 0;

Firmware/src/square.cpp

@@ -11,6 +11,9 @@ Lower frequency waves using nanoseconds is not needed and could actually causes
 // Use FASTRUN to run code in RAM
 FASTRUN void generateSquare(float frequency, int duty){
 
+  digitalWriteFast(DAC1_SEL, HIGH);
+  digitalWriteFast(DAC0_SEL, LOW);
+
     startGenerating();
     if(frequency < 1000){
       unsigned long periodMS = (1/ frequency) * pow(10, 6);      
@@ -42,5 +45,39 @@ FASTRUN void generateSquare(float frequency, int duty){
           delayCycles(dutyLowCycles);
       }
     }
+}
 
+FASTRUN void generateSquareDAC1(float frequency, int duty){
+
+    startGenerating();
+    if(frequency < 1000){
+      unsigned long periodMS = (1/ frequency) * pow(10, 6);      
+      unsigned long dutyHigh = periodMS * duty * 0.01;
+      unsigned long dutyLow = periodMS * duty * 0.01;
+
+      while(generateWave){
+          analogWriteDAC1(MAX_VALUE);
+          delayMicroseconds(dutyHigh);
+          analogWriteDAC1(0);
+          delayMicroseconds(dutyLow);
+      }
+
+    }else{
+      unsigned long periodNS = (1/ frequency) * pow(10, 9);
+
+      //Duration of the logic HIGH level
+      unsigned long dutyHigh = periodNS * duty * 0.01;
+      //Duration of the logic LOW level
+      unsigned long dutyLow = periodNS - dutyHigh;
+
+      unsigned long dutyHighCycles = (unsigned long) (dutyHigh/CLOCK_TO_NS);
+      unsigned long dutyLowCycles = (unsigned long)(dutyLow/CLOCK_TO_NS);
+
+      while(generateWave){
+          analogWriteDAC1(MAX_VALUE);
+          delayCycles(dutyHighCycles);
+          analogWriteDAC1(0);
+          delayCycles(dutyLowCycles);
+      }
+    }
 }

Firmware/src/wave.cpp

@@ -4,6 +4,9 @@
 #include "wave.h"
 
 void setupWaves(){
+  pinMode(DAC0_SEL, OUTPUT);
+  pinMode(DAC1_SEL, OUTPUT);
+
   // Info from teensy forum, access cycle counter. This will be needed for square waves in particular
   ARM_DEMCR |= ARM_DEMCR_TRCENA;
   ARM_DWT_CTRL |= ARM_DWT_CTRL_CYCCNTENA;