Diff: MicIO.cpp

Revision:

0:294495efee3f

Child:

1:1dfc4deed2cb

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MicIO.cpp	Sun Mar 23 00:45:30 2014 +0000
@@ -0,0 +1,125 @@
+#include "MicIO.h"
+#include "TextLCD.h"
+MicIO::MicIO(PinName micOut, PinName clockIn) : _micOut(micOut), _clockIn(clockIn) {
+    wait(0.015);        // Wait 15ms to ensure powered up
+    _genSinTable();    //Generate the sin table
+}
+
+TextLCD lcd(p24, p25, p26, p27, p28, p29);
+/* Send byte array through micIO */
+void MicIO::send(const char * inputStr, int length) {
+    unsigned char * outputStr;
+    outputStr = (unsigned char*) inputStr;
+    int numberOf4BitPairs = length * 2;
+    int current4BitIndex = 0;
+    int fourBits;
+    float sinSeed; //default at something ridculously high to stop an inf loop occuring
+    int clockState = clock(); //default the clock state to correct value
+    
+    /*
+                Parse out the 4 bits we're sending this clock cycle
+        */
+        if(current4BitIndex %2 == 0) { //upper 4 bits
+            fourBits = upper4Bits(outputStr[current4BitIndex/2]);
+        } else { //lower 4 bits
+            fourBits = lower4Bits(outputStr[current4BitIndex/2]);
+        }
+        sinSeed = _getSinSeed(fourBits); //get new sinSeed
+    
+    
+    while(current4BitIndex < numberOf4BitPairs) {
+        if(clock() == 0) { //Clock changed to high
+            
+            /*
+                Output sinusoid pulse
+            */
+             _sendSin(sinSeed);
+            /*
+                We're at the next clock cycle, and recieved a low. 
+                master done reading the sinusoid. Lets move on to the next 4bits
+            */
+            clockState = 0;
+            ++current4BitIndex;
+            /*
+                Parse out the next 4 bits we're sending this clock cycle
+            */
+            if(current4BitIndex %2 == 0) { //upper 4 bits
+                fourBits = upper4Bits(outputStr[current4BitIndex/2]);
+            } else { //lower 4 bits
+                fourBits = lower4Bits(outputStr[current4BitIndex/2]);
+            }
+            sinSeed = _getSinSeed(fourBits); //get new sinSeed
+        }
+    }
+}
+/* Read the current value of the input clock */
+int MicIO::clock() {
+    static int clockState = 0; //start clock @ low
+    float average = 0;
+    //ANalog In could have noise, averaging filter helps reduce it
+    for(int i = 0; i < 5; ++i) {
+        average += _clockIn.read();
+    }
+    average = average/5;
+    //Foce there to be high->low->high->low pattery w/clockState static int
+    if(average > 0.6 && clockState == 0){ //actually ~0.71
+        clockState = 1;
+        return 1;
+    } else if (average < 0.485 && clockState == 1) { //actually ~0.43
+        clockState = 0;
+        return 0;
+    } 
+    return -1; //NO CHANGE TO CLOCK
+}
+/* Extracts the lower 4 bits of a byte */
+unsigned char MicIO::lower4Bits(unsigned char byte) {
+    return (byte & 0x0F);
+}
+/* Extracts the upper 4 bits of a byte */
+unsigned char MicIO::upper4Bits(unsigned char byte) {
+    return (byte >> 4) & 0x0F;
+}
+/* Send a sin Wave  - bursts of 40 cycles*/
+void MicIO::_sendSin(float sinSeed) {
+    for(int c = 0; c < 50; ++c) {
+        for(float i = 0; i < 360; i+=sinSeed) {
+            _micOut = _sinTable[(int) i];
+        }
+    }
+    _micOut = 0.5; //Null Output
+        
+}
+/* Generate a sin Table */
+void MicIO::_genSinTable() {
+    for(int i = 0; i < 361; ++i) {
+        float temp = i;
+        _sinTable[i] = sin(temp/180*3.141)*0.5+0.5;
+    }
+}
+/* Go from 4 bits to a sin seed */
+float MicIO::_getSinSeed(unsigned char bits4) {
+    /*
+        By having sinSeed @ 1024 by default, if for some reason its not assigned, graceful
+        degradation occurs.
+    */
+    float sinSeed = 1024; //Default it to a large number for graceful degregation.
+    switch(bits4 & 0xF) { //switch just the 4 bits (force to 4 bits)
+        case 0x0 : sinSeed = 0.75; break;
+        case 0x1 : sinSeed = 1.00; break;
+        case 0x2 : sinSeed = 1.25; break;
+        case 0x3 : sinSeed = 1.50; break;
+        case 0x4 : sinSeed = 1.75; break;
+        case 0x5 : sinSeed = 2.00; break;
+        case 0x6 : sinSeed = 2.25; break;
+        case 0x7 : sinSeed = 2.50; break;
+        case 0x8 : sinSeed = 2.75; break;
+        case 0x9 : sinSeed = 3.00; break;
+        case 0xA : sinSeed = 3.25; break;
+        case 0xB : sinSeed = 3.50; break;
+        case 0xC : sinSeed = 3.75; break;
+        case 0xD : sinSeed = 4.00; break; 
+        case 0xE : sinSeed = 4.25; break;
+        case 0xF : sinSeed = 4.50; break;
+    }
+    return sinSeed;
+}