From cba63c074818afb0ac1c16a6aba25e73b5a95744 Mon Sep 17 00:00:00 2001
From: Colin <fireplanet.ca@gmail.com>
Date: Mon, 16 Feb 2015 00:14:16 -0500
Subject: [PATCH] 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 | 18 ++++++++++++++++--
 Talkie/talkie.h   |  1 +
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/Talkie/talkie.cpp b/Talkie/talkie.cpp
index ab850e5..edae320 100644
--- a/Talkie/talkie.cpp
+++ b/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
diff --git a/Talkie/talkie.h b/Talkie/talkie.h
index a56bcb3..2442d35 100644
--- a/Talkie/talkie.h
+++ b/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: