comparison core/I2c_Codec.cpp @ 145:8ff5668bbbad

Further updates and refactoring of the I2c_Codec class

 int I2c_Codec::startAudio(int dual_rate)
 {
 	// see datasehet for TLV320AIC3104 from page 44
 	if(writeRegister(0x02, 0x00))	// Codec sample rate register: fs_ref / 1
 		return 1;
+	//	The sampling frequency is given as f_{S(ref)} = (PLLCLK_IN × K × R)/(2048 × P)
+	// The master clock PLLCLK_IN is 12MHz
+	// K can be varied in intervals of resolution of 0.0001 up to 63.9999
+	// using P=8 and R=1 gives a resolution of 0.0732421875Hz ( 0.000166% at 44.1kHz)
+	// to obtain Fs=44100 we need to have K=60.2112
+
+	if(setPllP(8))
+		return 1;
+	if(setPllR(1))
+		return 1;
+	if(setAudioSamplingRate(44100)) //this will automatically find and set K for the given P and R so that Fs=44100
+		return 1;
 //	if(writeRegister(0x03, 0x91))	// PLL register A: enable
 //		return 1;
-	if(setPllP(1))
-		return 1;
 //	if(writeRegister(0x04, 0x1C))	// PLL register B
 //		return 1;
 //	if(writeRegister(0x05, 0x52))	// PLL register C
 //		return 1;
 //	if(writeRegister(0x06, 0x40))	// PLL register D
 //		return 1;
-	if(setPllD(5264)) //7.5264 gives 44.1kHz nominal value with a 12MHz master clock
-		return 1;
-	if(setPllJ(7))
-		return 1;
+//	if(writeRegister(0x0B, 0x01))	// Audio codec overflow flag register: PLL R = 1
+//		return 1;
+
+//	if(setPllD(5264)) //7.5264 gives 44.1kHz nominal value with a 12MHz master clock
+//		return 1;
+//	if(setPllJ(7))
+//		return 1;
 	if(dual_rate) {
 		if(writeRegister(0x07, 0xEA))	// Codec datapath register: 44.1kHz; dual rate; standard datapath
 			return 1;
 	}
 	else {

 	if(writeRegister(0x08, 0xC0))	// Audio serial control register A: BLCK, WCLK outputs
 		return 1;
 	if(writeRegister(0x09, 0x40))	// Audio serial control register B: DSP mode, word len 16 bits
 		return 1;
 	if(writeRegister(0x0A, 0x00))	// Audio serial control register C: 0 bit offset
-		return 1;
-//	if(writeRegister(0x0B, 0x01))	// Audio codec overflow flag register: PLL R = 1
-//		return 1;
-	if(setPllR(1))
 		return 1;
 	if(writeRegister(0x0C, 0x00))	// Digital filter register: disabled
 		return 1;
 	if(writeRegister(0x0D, 0x00))	// Headset / button press register A: disabled
 		return 1;

 		}
 	pllR = r;
 	return 0;
 }
 int I2c_Codec::setAudioSamplingRate(float newSamplingRate){
-	int pllP=getPllP(); //TODO: create get/set for pllP and pllR
-	int pllR=1;
 	long int PLLCLK_IN=12000000;
 	//	f_{S(ref)} = (PLLCLK_IN × K × R)/(2048 × P)
 	float k = ((double)(newSamplingRate * pllP * 2048.0f/(float)pllR)) / PLLCLK_IN ;
 	return (setPllK(k));
 }