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christophediericx/cga.ino

Created September 11, 2016 02:23
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cga.ino
#define HSYNC 8
#define VSYNC 16
#define ROWS 261
const byte buf[1][200] = {
{ 0, 5, 4, 3, 2, 1, 6, 7, 1, 2 , 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2 /* 100 */, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2, 0, 5, 4, 3, 2, 1, 6, 7, 1, 2 /* 200 */ }
};
#define SETC(x) PORTB = (PORTB & ~7) | x
#define EXEC_NOP asm volatile ("nop\n\t")
#define EXEC_10_NOPS EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP;
#define EXEC_50_NOPS EXEC_10_NOPS; EXEC_10_NOPS; EXEC_10_NOPS; EXEC_10_NOPS; EXEC_10_NOPS;
#define EXEC_100_NOPS EXEC_50_NOPS; EXEC_50_NOPS;
#define EXEC_LEFT_BLANKING_AND_OVERSCAN() { EXEC_50_NOPS; SETC(0); EXEC_10_NOPS; EXEC_NOP; EXEC_NOP; EXEC_NOP; }
#define EXEC_RIGHT_OVERSCAN_AND_BLANKING() { SETC(0); EXEC_50_NOPS; EXEC_50_NOPS; EXEC_10_NOPS; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; EXEC_NOP; }
#define EXEC_HSYNC() { PORTB |= HSYNC; EXEC_50_NOPS; EXEC_10_NOPS; EXEC_10_NOPS; EXEC_NOP; PORTB &= ~HSYNC; }
#define DRAW_PIXELS_FOR_LINE(i) { \
SETC(buf[i][0]); \
SETC(buf[i][1]); \
SETC(buf[i][2]); \
SETC(buf[i][3]); \
SETC(buf[i][4]); \
SETC(buf[i][5]); \
SETC(buf[i][6]); \
SETC(buf[i][7]); \
SETC(buf[i][8]); \
SETC(buf[i][9]); \
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SETC(buf[i][20]); \
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SETC(buf[i][22]); \
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SETC(buf[i][24]); \
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SETC(buf[i][27]); \
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SETC(buf[i][36]); \
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SETC(buf[i][161]); \
SETC(buf[i][162]); \
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SETC(buf[i][166]); \
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SETC(buf[i][178]); \
SETC(buf[i][189]); \
SETC(buf[i][190]); \
SETC(buf[i][191]); \
SETC(buf[i][192]); \
SETC(buf[i][193]); \
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SETC(buf[i][196]); \
SETC(buf[i][197]); \
SETC(buf[i][198]); \
SETC(buf[i][199]); \
}
#define DRAW_LINE(i) { \
EXEC_LEFT_BLANKING_AND_OVERSCAN(); \
DRAW_PIXELS_FOR_LINE(i); \
EXEC_RIGHT_OVERSCAN_AND_BLANKING(); \
EXEC_HSYNC(); \
}
int row = ROWS;
void setup() {
DDRB = B111111;
PORTB &= ~(HSYNC | VSYNC | 7);
noInterrupts();
}
void loop() {
DRAW_LINE(0);
switch (row++) {
case 225:
PORTB |= VSYNC; // VSYNC HIGH
break;
case 228:
PORTB &= ~VSYNC; // VSYNC LOW
break;
case 261:
row = 0;
break;
}
}
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