matrix.ino

/*
* Modified by Frederic Drago to display a panel using 24 bits hex colors and gamma correction
 * Modified by Markus Lipp adding interleaved buffers, streaming, 32x32 & 24bit support
 * Based on "_16x32_Matrix R3.0" by Creater Alex Medeiros, http://PenguinTech.tk
 * Use code freely and distort its contents as much as you want, just remeber to thank the 
 * original creaters of the code by leaving their information in the header. :)
 */

//PortA[4:5, 12:13] = {33, 24, 3, 4}
//PortB[0:3, 16:19] = {16, 17, 19, 18, 0, 1, 32, 25}
//PortC[0:11] = {15, 22, 23, 9, 10, 13, 11, 12, 28, 27, 29, 30}
//PortD[0:7] = {2, 14, 7, 8, 6, 20, 21, 5}
//PortE[0:1] = {31, 26}

// Define pins (if you cannot use portB, since pin 32 is not available by default on the Teensy, portC must be used, 
// then change also GPIOB to GPIOC in the code.

const uint8_t
//PortC
//APIN  = 15, BPIN = 22, CPIN = 23, DPIN = 9, CLOCKPIN = 10, LATCHPIN = 13, OEPIN = 11,

//PortB
APIN = 16, BPIN = 17, CPIN = 19, DPIN = 18, CLOCKPIN  = 0, LATCHPIN  = 1, OEPIN = 32,
//PortD
R1PIN = 2, R2PIN = 8,
G1PIN = 14, G2PIN = 6,
B1PIN = 7, B2PIN = 20;

uint8_t pinTable[13] = {
    R1PIN,R2PIN,G1PIN,G2PIN,B1PIN,B2PIN,
    APIN,BPIN,CPIN,DPIN,CLOCKPIN,LATCHPIN,OEPIN};

//Addresses 1/8 rows Through a decoder
uint16_t const A = 1, B = 2,C = 4, D=8;
//Acts like a 16 bit shift register
uint32_t const SCLK   = 65536;//16 if using portC
uint32_t const LATCH  = 131072;//32 if using portC
uint32_t const OE     = 262144;//64 if using portC

uint16_t const abcVar[16] = { //Decoder counter var
    //   0,A,B,A+B,C,C+A,C+B,A+B+C,0+D,A+D,B+D,A+B+D,C+D,C+A+D,C+B+D,A+B+C+D};
  0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
//Data Lines for row 1 red and row 9 red, ect.
uint16_t const RED1   = 1, RED2   = 8;
uint16_t const GREEN1 = 2, GREEN2 = 16;
uint16_t const BLUE1  = 4, BLUE2  = 32;

const uint8_t SIZEX = 32;
const uint8_t SIZEY = 32;

//BAM and interrupt variables
uint8_t rowN = 0;
uint16_t BAM;
uint8_t BAMMAX = 7; //now 24bit color! (0-7)
IntervalTimer timer1;

uint8_t gImage[1024][3];
uint8_t gr, gg, gb;

uint8_t r, g, b;
char buffer[120]; 
int bufidx = 0; 
char c;
int i = 0;
int color = 0;

// -------------------------------- sample image to display by default -----------------------------------------------------
static int hello[1024] = {
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,
0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,
0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFFFFFF,0x000000,
0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x00000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,
0x000000,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0xFBA904,
0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0x000000,0xFFFFFF,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0x000000,0x000000,
0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,
0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFFFFFF,0x000000,0x000000,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,
0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,
0x000000,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,
0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0x000000,0x000000,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0x000000,0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0x000000,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0x000000,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,
0xFBA904,0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0x000000,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0xFBA904,0x000000,0x000000,0xFFFFFF,0xFFFFFF,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0x000000,0xFFFFFF,0xFFFFFF,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFC02B5,0xFC02B5,0xFC02B5,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFB0412,0xFB0412,0xFB0412,0xFFFFFF,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0x000000,
0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFC02B5,0xF7FB04,0xF7FB04,0xF7FB04,0xFC02B5,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFB0412,0xF7FB04,0xF7FB04,0xF7FB04,0x000000,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0x000000,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFC02B5,0xF7FB04,0xF7FB04,0xF7FB04,0xFC02B5,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFB0412,0xF7FB04,0xF7FB04,0xF7FB04,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFC02B5,0x2AF60A,0xFC02B5,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFB0412,0x2AF60A,0xFB0412,0x000000,0xFB0412,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0x000000,0xFB0412,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x2AF60A,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x2AF60A,0xFFFFFF,0x000000,0xFB0412,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0x000000,0xFB0412,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x2AF60A,0xFFFFFF,0x2AF60A,0xFFFFFF,0x2AF60A,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x2AF60A,0x2AF60A,0x2AF60A,0x000000,0xFB0412,0x000000,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0xFB0412,0x000000,0xFB0412,
0x000000,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF,0x2AF60A,0x2AF60A,0x2AF60A,0xFFFFFF,0xFFFFFF,0xFFFFFF,0xFFFFFF
};

// ----------------------------------------------------------------------------------------------------------------------------------
void setup() {
    for(uint8_t i = 0; i < 13; i++){
        pinMode(pinTable[i], OUTPUT);
    }
    // Prepare a default image
    for (int i = 0; i < 1024; i++) {
        gammaCorrect(hello[i]);
        gImage[i][0] = gr;
        gImage[i][1] = gg;
        gImage[i][2] = gb;
    }
    Serial.begin(250000);
    timerInit();
}
// ----------------------------------------------------------------------------------------------------------------------------------
void loop() {      

     // Normal serial from USB
     // format to change a led is c,led number, color in hexadecimal ex: c,0,FF00FF (will change the first led to magenta)
    Serial.flush();
    if (Serial.available() > 0) { 
        c = (char)Serial.read(); 
        buffer[bufidx++] = c; 

        if (c == '\n') { 
            buffer[bufidx++] = '\n'; 
            bufidx = 0; 
            parseBuffer(); 
            //gammaCorrectRGB(r, g, b); // works but takes too much time (could use a table), implemented in processing anyway
            gImage[i][0] = r;
            gImage[i][1] = g;
            gImage[i][2] = b;    
        } 
    } 
  
}
// ---------------------------------------------------END LOOP----------------------------------------------------------------

void timerInit() {
    BAM = 0;
    attackMatrix();
}

//The updating matrix stuff happens here
//each pair of rows is taken through its BAM cycle
//then the rowNumber is increased and is done again
void attackMatrix() {
    timer1.end();    

    uint16_t portData;
    portData = 0; // Clear data to enter
    portData |= (abcVar[rowN])|OE; // abc, OE
    portData &=~ LATCH;        //LATCH LOW
    GPIOB_PDOR = portData;  // Write to Port
    
    for(uint8_t i = 0; i < 32; i++){
        uint16_t row = (rowN<<5)+i;
        uint16_t row16 = ((rowN+16)<<5)+i;
        uint16_t tempC[6] = { //Prepare data in correct place
            ((gImage[row][0])<<1)   , ((gImage[row16][0])<<4), //3
            ((gImage[row][1])<<1), ((gImage[row16][1])<<4), //4
            (gImage[row][2]<<1), (gImage[row16][2])<<4          };  //6         
        uint16_t allC =//Put OUTPUT data into temp variable
        ((tempC[0]>>BAM)&RED1)|((tempC[1]>>BAM)&RED2)|
            ((tempC[2]>>BAM)&GREEN1)|((tempC[3]>>BAM)&GREEN2)|
            ((tempC[4]>>BAM)&BLUE1)|((tempC[5]>>BAM)&BLUE2);

        GPIOD_PDOR = (allC); // Transfer data    
        GPIOB_PDOR |=  SCLK;// Clock HIGH
        GPIOB_PDOR &=~ SCLK;// Clock LOW
    }

    GPIOB_PDOR |= LATCH;// Latch HIGH
    GPIOB_PDOR &=~ OE;// OE LOW, Displays line

#define LOOPTIME 1 //trial&error to get both smooth gradients & little flicker
#define CALLOVERHEAD 1
    timer1.begin(attackMatrix,((LOOPTIME+CALLOVERHEAD)<<BAM)-CALLOVERHEAD);

    if(BAM >= BAMMAX) { //Checks the BAM cycle for next time.    
        if(rowN == 15){
            rowN = 0;
        } 
        else {
            rowN ++;
        }        
        BAM = 0;
    } 
    else {
        BAM ++;
    }
}

// Choose appropriate gamma value by comparison with computer monitor
void gammaCorrect(int pixel)
{
    float gammaCorrect = 1.0 /0.28;
    gr = uint8_t((255.0 * (pow(((pixel  >> 16) & 0xFF) / 255.0, gammaCorrect))));
    gg = uint8_t((255.0 * (pow(((pixel  >> 8) & 0xFF) / 255.0, gammaCorrect))));
    gb = uint8_t((255.0 * (pow((pixel  & 0xFF) / 255.0, gammaCorrect))));
    // following gives the best color reproduction, however brightness is lost
//  float gammaCorrect = 1.0 /0.45;
 //   gr = uint8_t((255.0 * (pow(((pixel  >> 16) & 0xFF) / 255.0, gammaCorrect)))*0.33);
 //   gg = uint8_t((255.0 * (pow(((pixel  >> 8) & 0xFF) / 255.0, gammaCorrect))))*0.33;
 //   gb = uint8_t((255.0 * (pow((pixel  & 0xFF) / 255.0, gammaCorrect)))*0.15);
}

void gammaCorrectRGB(uint8_t r, uint8_t g, uint8_t b)
{
    float gammaCorrect = 1.0 /0.28;
    gr = uint8_t((255.0 * (pow(r / 255.0, gammaCorrect))));
    gg = uint8_t((255.0 * (pow(g / 255.0, gammaCorrect))));
    gb = uint8_t((255.0 * (pow(b / 255.0, gammaCorrect))));
}

void hexToColor(int pixel)
{
    gr = uint8_t((pixel  >> 16) & 0xFF);
    gg = uint8_t((pixel  >> 8) & 0xFF);
    gb = uint8_t(pixel  & 0xFF);   
}

void parseBuffer(void) 
{ 
    char *parseptr; 
    
    if (strncmp(buffer,"C",1) == 0 || strncmp(buffer,"c",1) == 0){ 
        parseptr = strchr(buffer, ',')+1; 
        i = parsenumber(parseptr,0); 
        parseptr = strchr(parseptr, ',')+1;
        r = parseHex(parseptr[0])* 16 + parseHex(parseptr[1]) ; 
        g = parseHex(parseptr[2])* 16 + parseHex(parseptr[3]) ; 
        b = parseHex(parseptr[4])* 16 + parseHex(parseptr[5]) ; 
    } 
} 

// Function to parse fixed point numbers (numdec=number of decimals) 
long parsenumber(char *str,byte numdec) { 
    long d = 0; 
    byte ndec = 0; 

    while (str[0] != 0) { 
        if (str[0] == '.'){ 
            ndec = 1; 
        } 
        else { 
            if ((str[0] > '9') || (str[0] < '0')) 
                return d; 
            d *= 10; 
            d += str[0] - '0'; 
            if (ndec > 0) 
                ndec++; 
            if (ndec > numdec)   // we reach the number of decimals... 
                return d; 
        } 
        str++; 
    } 
    return d; 
} 

byte parseHex(char c) { 
    if (c < '0') 
        return (0); 
    if (c <= '9') 
        return (c - '0'); 
    if (c < 'A') 
        return (0); 
    if (c <= 'F') 
        return ((c - 'A')+10); 
}