Added Volume Support

You may now set the output volume digitally using the added setVol()
function.

It takes one parameter, which is the desired volume in percent, 0-255. A
value of 100 will output the 'Max' volume, which is the normal volume
outputted by the recording.  A value of zero is mute, and a value
greater then 100 will actually boost the original volume.

Careful when boosting, if you go to high, the audio will distort when
the waveform peaks hit the roof and gets clipped off.

Talkie/talkie.cpp

@@ -30,6 +30,8 @@ int8_t tmsK8[0x08]      = {0xC0,0xD8,0xF0,0x07,0x1F,0x37,0x4F,0x66};
 int8_t tmsK9[0x08]      = {0xC0,0xD4,0xE8,0xFC,0x10,0x25,0x39,0x4D};
 int8_t tmsK10[0x08]     = {0xCD,0xDF,0xF1,0x04,0x16,0x20,0x3B,0x4D};
 
+float volumeMult = 1;	//Volume Multiplier to boost or shrink PWM strength. (1 = Normal volume)
+
 void Talkie::setPtr(uint8_t* addr) {
 	ptrAddr = addr;
 	ptrBit = 0;
@@ -143,6 +145,15 @@ void Talkie::say(uint8_t* addr) {
 	} while (energy != 0xf);
 }
 
+//Sets the volume in percentage
+//0=Mute, 100=Max(normal), 100+ = boosted
+//
+void Talkie::setVol(uint8_t volume) {
+	//Calculate the volume multiplier
+	volumeMult = volume*0.01;
+}
+
+
 #define CHIRP_SIZE 41
 int8_t chirp[CHIRP_SIZE] = {0x00,0x2a,0xd4,0x32,0xb2,0x12,0x25,0x14,0x02,0xe1,0xc5,0x02,0x5f,0x5a,0x05,0x0f,0x26,0xfc,0xa5,0xa5,0xd6,0xdd,0xdc,0xfc,0x25,0x2b,0x22,0x21,0x0f,0xff,0xf8,0xee,0xed,0xef,0xf7,0xf6,0xfa,0x00,0x03,0x02,0x01};
 
@@ -151,8 +162,11 @@ ISR(TIMER1_COMPA_vect) {
   static uint8_t periodCounter;
   static int16_t x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,x10;
   int16_t u0,u1,u2,u3,u4,u5,u6,u7,u8,u9,u10;
-
-  OCR2B = nextPwm;
+
+  uint16_t pwmWithVol = (uint16_t)(nextPwm * volumeMult);  	//Apply volume multiplier to pwm signal
+  if (pwmWithVol > 255) { pwmWithVol = 255; }				//Clamp waveform at 255 max peak
+  OCR2B = (uint8_t) pwmWithVol;								//Set PWM register
+
   sei();
   if (synthPeriod) {
     // Voiced source

Talkie/talkie.h

@@ -13,6 +13,7 @@ class Talkie
 {
 	public:
 		void say(uint8_t* address);
+		void setVol(uint8_t volume); //Set volume by percentage
 		uint8_t* ptrAddr;
 		uint8_t ptrBit;
 	private: