control_aic3206: clarify that volume_dB() changes the DAC volume, not…

… the headphone amp

src/control_aic3206.cpp

@@ -481,7 +481,7 @@ bool AudioControlAIC3206::enableAutoMuteDAC(bool enable, uint8_t mute_delay_code
 	return enable;
 }
 
-// -63.6 to +24 dB in 0.5dB steps.  uses signed 8-bit
+// Changes the DAC ouput volume from -63.6 dB to +24 dB in 0.5dB steps.  uses signed 8-bit
 float AudioControlAIC3206::applyLimitsOnVolumeSetting(float vol_dB) {
 	// Constrain to limits
 	if (vol_dB > 24.0) {
@@ -494,6 +494,7 @@ float AudioControlAIC3206::applyLimitsOnVolumeSetting(float vol_dB) {
 	}
 	return vol_dB;
 }
+// Changes the DAC ouput volume from -63.6 dB to +24 dB in 0.5dB steps.  
 float AudioControlAIC3206::volume_dB(float orig_vol_dB, int Ichan) {  // 0 = Left; 1 = right;
 	float vol_dB = applyLimitsOnVolumeSetting(orig_vol_dB);
 	if (abs(vol_dB - orig_vol_dB) > 0.01) {

src/control_aic3206.h

@@ -78,9 +78,9 @@ class AudioControlAIC3206: public TeensyAudioControl
 	virtual bool disable(void);
 	bool outputSelect(int n, bool flag_full = true); //flag_full is whether to do a full reconfiguration.  True is more complete but false is faster.
 	bool volume(float n);
-	static float applyLimitsOnVolumeSetting(float vol_dB);
-	float volume_dB(float vol_dB);  //set both channels to the same volume
-	float volume_dB(float vol_left_dB, float vol_right_dB); //set both channels, but to their own values
+	static float applyLimitsOnVolumeSetting(float vol_dB);  //uses limits (using the limits on the DAC gain in the AIC)
+	float volume_dB(float vol_dB);  //set both channels to the same volume (via the DAC output volume)
+	float volume_dB(float vol_left_dB, float vol_right_dB); //set both channels (via the DAC output volume), but to their own values
 	float volume_dB(float vol_left_dB, int chan); //set each channel seperately (0 = left; 1 = right)
 	int muteDAC(int chan = BOTH_CHAN);  //mutes the output DAC
 	int unmuteDAC(int chan = BOTH_CHAN); //unmutes the output DAC

src/output_i2s_f32.cpp

@@ -844,6 +844,8 @@ void AudioOutputI2S_F32::config_i2s(float fs_Hz) { config_i2s(false, fs_Hz); }
 void AudioOutputI2S_F32::config_i2s(bool transferUsing32bit, float fs_Hz)
 {
 #if defined(KINETISK) || defined(KINETISL)
+	//Tympan Revs A-D will be here (based on Teensy 3.6, which is Kinetis K)
+
 	SIM_SCGC6 |= SIM_SCGC6_I2S;
 	SIM_SCGC7 |= SIM_SCGC7_DMA;
 	SIM_SCGC6 |= SIM_SCGC6_DMAMUX;
@@ -887,7 +889,8 @@ void AudioOutputI2S_F32::config_i2s(bool transferUsing32bit, float fs_Hz)
 
 
 #elif defined(__IMXRT1062__)
-
+	//Tympan Revs E-F will be here (based on Teensy 4.1, which is IMXRT1062)
+
 	CCM_CCGR5 |= CCM_CCGR5_SAI1(CCM_CCGR_ON);
 
 	// if either transmitter or receiver is enabled, do nothing