Chua chaotic oscillator example
/* Chua Chaotic Oscillator v1.0 */
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;
byte fb[240][320];
#define do20(x) x x x x x x x x x x x x x x x x x x x x
#define do80(x) do20(x) do20(x) do20(x) do20(x)
#define do320(x) do80(x) do80(x) do80(x) do80(x)
#define MNOP(x) asm volatile (" .rept " #x "\n\t nop \n\t .endr \n\t")
void TC0_Handler()
{
long dummy=REG_TC0_SR0;
if(line < 480){
byte * p=fb[line>>1];
MNOP(160);
do320(REG_PIOD_ODSR = *p++;MNOP(2);)
REG_PIOD_ODSR = 0;
}
if(line==490) digitalWriteDirect(3,1); //or digitalWriteDirect(3,0); to invert vsync
if(line==492) digitalWriteDirect(3,0); //or digitalWriteDirect(3,1); to invert vsync
line++; if(line == 525) line=0;
}
void setup(){
pinMode(3,OUTPUT); pinMode(2,OUTPUT); // vsync=3 hsync=2
pinMode(25,OUTPUT); pinMode(26,OUTPUT); // blue (26=msb,25=lsb)
pinMode(27,OUTPUT); pinMode(28,OUTPUT); pinMode(14,OUTPUT); // green (14=msb,28,27=lsb)
pinMode(15,OUTPUT); pinMode(29,OUTPUT); pinMode(11,OUTPUT); // red (11=msb,29,15=lsb)
REG_PIOD_OWER= 0xff;
REG_PMC_PCER0= 1<<27;
REG_PIOB_PDR = 1<<25;
REG_PIOB_ABSR= 1<<25;
REG_TC0_WPMR = 0x54494D00;
REG_TC0_CMR0 = 0b00000000000010011100010000000000;
// REG_TC0_CMR0 = 0b00000000000001101100010000000000; // this inverts hsync
REG_TC0_RC0 = 1334;
REG_TC0_RA0 = 1174;
REG_TC0_CCR0 = 0b101;
REG_TC0_IER0 = 0b00010000;
REG_TC0_IDR0 = 0b11101111;
NVIC_EnableIRQ(TC0_IRQn);
}
float x = 0.5;
float y = 0.25;
float z = 0.125;
float h = 0;
float dt = 0.005;
float alpha = 15.6;
float beta = 28.58;
float a = -1.14286;
float b = -0.714286;
void loop(){
float oldx = x;
float oldy = y;
float oldz = z;
h = (b * x) + (0.5 * (a - b) * (abs(x+1) - abs(x-1)));
x = oldx + dt * (alpha * (oldy - oldx - h));
y = oldy + dt * (oldx - oldy + oldz);
z = oldz + dt * (-beta * oldy);
fb[120+int(65*4*y)][160+int(65*x)]=255;
}