VGA output

Hardware Arduino Due
31

SVGA Quadrup Two Orbit Fractal :slight_smile:

/* Quadrup Two Orbit Fractal v1.1 by JLS 2012 */

/* Arduino Due SVGA-Out 800x600 v0.3 by stimmer
http://arduino.cc/forum/index.php/topic,130742.0.html 
Please do not attempt to understand this code :-) */

int bins[256];
void  __attribute__((aligned(64))) doLine(byte *p){
        asm volatile (        
        "isb \n\t"
        "dsb \n\t" 
        "movw r1,#0x4254 \n\t"
        "movt r1,#0x4009 \n\t"
        "ldr r0,[r1] \n\t"
        "subs r0,#40 \n\t"
        "lsls r0,r0,#1 \n\t"
        "orr r0,#1 \n\t"  
        "add r0,pc \n\t"
        "isb \n\t"
        ".align 5 \n\t"
        "bx r0 \n\t"
        ".rept 90 \n\t"
        "nop \n\t"
        ".endr \n\t"
                
        //this is debugging code, but because the timimg is so sensitive I have to leave it in
        "ldr r0,[r1] \n\t"
        "subs r0,#128 \n\t"
        "ldr r2,[%[bins],r0,lsl #2] \n\t"
        "adds r2,#1 \n\t"
        "str r2,[%[bins],r0,lsl #2] \n\t" 
        
        //"movw r1,#0x40DC \n\t"
        //"movt r1,#0x400C \n\t"
        //"str %[bytes],[r1] \n\t"
        "movw r1,#0x40E8 \n\t"
        "movt r1,#0x400C \n\t"
        "movw r0,26 \n\t"
        "movt r0,#0x1203 \n\t"
        "str r0,[r1] \n\t"
        "movw r1,#0x4028 \n\t"
        "movt r1,#0x400C \n\t"
        "mov r0,1<<4 \n\t"
        "str r0,[r1] \n\t"
        "movw r1,#0x0e04 \n\t"
        "movt r1,#0x400e \n\t"
        "mov r0,1<<26 \n\t"
        ".rept 12\n\t nop\n\t .endr\n\t"
        "str r0,[r1] \n\t"
              
        :[bytes]"+r"(p)
        :[bins]"r"(bins)
        :"r0","r1","r2"
        );  
          
}

void __attribute__((aligned(64))) DMAC_Handler()
{
    REG_PIOA_PER  = 1<<26;     
    uint32_t dummy=REG_DMAC_EBCISR;
}

inline void digitalWriteDirect(int pin, boolean val){
  if(val) g_APinDescription[pin].pPort -> PIO_SODR = g_APinDescription[pin].ulPin;
  else    g_APinDescription[pin].pPort -> PIO_CODR = g_APinDescription[pin].ulPin;
}

volatile short line;
uint16_t fb[600][52] __attribute__((aligned(256)));

void __attribute__((aligned(64))) PWM_Handler()
{
    long dummy=REG_PWM_ISR1; 
                 
    if(line < 600){        
        //byte * p=fb[line];
        doLine(0);
    }      
    if(line==601) digitalWriteDirect(42,1); //or digitalWriteDirect(42,0); to invert vsync
    if(line==605) digitalWriteDirect(42,0); //or digitalWriteDirect(42,1); 
    
    line++; if(line == 628){
      REG_DMAC_SADDR4=(uint32_t)fb;
      line=0;
    }
}

void setup(){
    
  pinMode(42,OUTPUT); pinMode(43,OUTPUT);                     // vsync=42 hsync=43
  // video output is on SPI MOSI pin (bottom middle on SAM3 3x2 SPI connector)                                      
  
  REG_PIOA_PDR  =1<<20;
  REG_PIOA_ABSR|=1<<20;
  REG_PMC_PCER1= 1<<4;
  REG_PWM_WPCR= 0x50574dfc;
  REG_PWM_CLK= 0x00010001;
  REG_PWM_DIS= 1<<2;
  REG_PWM_CMR2=0x0;   //  REG_PWM_CMR2=0x200;  //to invert hsync polarity
  REG_PWM_CPRD2=2218;
  REG_PWM_CDTY2=1949;
  REG_PWM_SCM=0;
  REG_PWM_IER1=1<<2;
  REG_PWM_ENA= 1<<2;  
  NVIC_EnableIRQ(PWM_IRQn);

  REG_PMC_PCER1= 1<<7;  
  REG_DMAC_WPMR=DMAC_WPMR_WPKEY(0x444d4143);
  REG_DMAC_EN=1;
  REG_DMAC_GCFG=0x00;
  REG_DMAC_EBCIER=1<<4;
  REG_DMAC_DADDR4=(uint32_t)&REG_SPI0_TDR;  
  REG_DMAC_DSCR4=0;
  REG_DMAC_CTRLB4=0x20310000;
  REG_DMAC_CFG4=  0x01412210;
    
  NVIC_EnableIRQ(DMAC_IRQn);

  REG_PIOA_PDR  = (1<<25)|(1<<27)|(1<<28);
  REG_PIOA_PER  = 1<<26;
  REG_PIOA_ABSR&=~((1<<25)|(1<<27)|(1<<28));
  REG_PMC_PCER0= 1<<24;
  REG_SPI0_WPMR=0x53504900; 
  REG_SPI0_CR=0x1;
  REG_SPI0_MR=0x00000011;
  SPI0->SPI_CSR[0]=0x00000280; 
  
  Serial.begin(9600);
}

inline void putPixel(int x,int y,byte c=1){
  if((x<0)||(x>=800)||(y<0)||(y>=600))return;
  uint16_t mask=1<<((~x)&15);
  if(c) fb[y][x>>4]|= mask;
  else  fb[y][x>>4]&=~mask;
}

inline int getPixel(int x,int y){
  if((x<0)||(x>=800)||(y<0)||(y>=600))return -1;
  uint16_t mask=1<<((~x)&15);
  return (fb[y][x>>4] & mask)?1:0;
}

#define sgn(x) (((x)>0)?1:((x)<0)?-1:0)
void drawLine(int x0, int y0, int x1, int y1,int c){
   int dx=abs(x1-x0), dy=abs(y1-y0),sx=sgn(x1-x0),sy=sgn(y1-y0);
   int err=dx-dy; 
   do{ putPixel(x0,y0,c<2?c:!getPixel(x0,y0));
       int e2=2*err;
       if (e2 > -dy){err-=dy;x0+=sx;}
       if (e2 <  dx){err+=dx;y0+=sy;}
   }   while ((x0!=x1)||(y0!=y1));
}

    float a = 34;
    float b = 0.9;
    float c = 5;
    float x = 1;
    float y = 0;
   
    int xx,yy;
   
    int cnt = 0;
    int col = 1;

void loop(){  
         
    double oldx = x;
    double oldy = y;
    
    x = oldy-(oldx/abs(oldx))*sin(log(abs(b*oldx-c)))*atan(abs((pow(c*oldx-b,2))));
    y = a-oldx;
    
    xx = 285+7*x;
    yy = 210+5.5*y;
    
    if (cnt == 1000) {
	col = rand()%2;
	cnt = 0; }
		
    cnt++; 
    
    if ((xx>=0)&(xx<=799)&(yy>=0)&(yy<=599)) putPixel(xx,yy,col);
}