Test sample rates for CW Modulator

Author: boblark

examples/CWSendTest4Rate/CWSendTest4Rate.ino

@@ -0,0 +1,88 @@
+/*
+* CWSendTest4Rate.ino  Test the
+* F32 library CW Modulator at four sample rates.
+* Bob Larkin 29 August 2025
+* Public Domain
+*/
+
+// This is a test of the CW Modulator
+// Runs at 12, 24, 48 and 96 ksps.  Sends a test string out
+// to both Left and Right channels.
+
+#include "OpenAudio_ArduinoLibrary.h"
+#include "AudioStream_F32.h"
+#include <Audio.h>
+// Next include has set_audioClock(  )
+#include <utility/imxrt_hw.h> 
+
+radioCWModulator_F32     CWMod1;         //xy=414,332
+AudioOutputI2S_F32       audioOutI2S1;   //xy=595,327
+AudioConnection_F32      patchCord1(CWMod1, 0, audioOutI2S1, 0);
+AudioConnection_F32      patchCord2(CWMod1, 0, audioOutI2S1, 1);
+AudioControlSGTL5000     sgtl5000_1;     //xy=509,390
+
+char test12Str[] = "test 12  ";
+char test24Str[] = "test 24  ";
+char test48Str[] = "test 48  ";
+char test96Str[] = "test 96  ";
+
+void setup(void)
+   {
+   Serial.begin(9600);
+   delay(1000);
+   AudioMemory_F32(20);
+   Serial.println("Test CW Transmit");
+
+   setI2SFreq(12000);                  // Sets I2S clocks
+
+   CWMod1.setSampleRate_Hz(12000.0f);  // Sets CW functions, only
+   CWMod1.setCWSpeedWPM(13);
+   CWMod1.setFrequency(700.0f);
+   CWMod1.amplitude(0.3f);  // <== IMPORTANT Set before using headphones
+   CWMod1.sendStringCW(test12Str);
+   CWMod1.enableTransmit(true);
+   Serial.println("Going to 12 ksps Sample Rate");
+   while(CWMod1.getBufferSpace() < 512) delay(1);  // Send at 12 ksps
+
+   setI2SFreq(24000);
+   CWMod1.setSampleRate_Hz(24000.0f);
+   CWMod1.sendStringCW(test24Str);
+   Serial.println("Going to 24 ksps Sample Rate");
+   while(CWMod1.getBufferSpace() < 512) delay(1);   // Send at 24 ksps
+
+   setI2SFreq(48000);
+   CWMod1.setSampleRate_Hz(48000.0f);
+   CWMod1.sendStringCW(test48Str);
+   Serial.println("Going to 48 ksps Sample Rate");
+   while(CWMod1.getBufferSpace() < 512) delay(1);   // Send at 48 ksps
+
+   setI2SFreq(96000);
+   CWMod1.setSampleRate_Hz(96000.0f);
+   CWMod1.sendStringCW(test96Str);
+   Serial.println("Going to 96 ksps Sample Rate");
+   while(CWMod1.getBufferSpace() < 512) delay(1);   // Send at 96 ksps
+   delay(5);
+
+   Serial.println("End of Transmission");
+   }
+
+void loop(void)
+   {
+   delay(1);
+   }
+
+// Frank B's routine for setting I2S clocks. *** FOR T4.x ONLY ***
+void setI2SFreq(int freq1)    // Thank ypu, Frank B.
+   {
+   // PLL between 27*24 = 648MHz und 54*24=1296MHz
+   int n1 = 4; //SAI prescaler 4 => (n1*n2) = multiple of 4
+   int n2 = 1 + (24000000 * 27) / (freq1 * 256 * n1);
+   double C = ((double)freq1 * 256 * n1 * n2) / 24000000;
+   int c0 = C;
+   int c2 = 10000;
+   int c1 = C * c2 - (c0 * c2);
+   set_audioClock(c0, c1, c2, true);
+   CCM_CS1CDR = (CCM_CS1CDR & ~(CCM_CS1CDR_SAI1_CLK_PRED_MASK | CCM_CS1CDR_SAI1_CLK_PODF_MASK))
+       | CCM_CS1CDR_SAI1_CLK_PRED(n1-1)                                // &0x07
+       | CCM_CS1CDR_SAI1_CLK_PODF(n2-1);                               // &0x3f 
+   }