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#define HAVE_TICK
static union {
uint32_t u32;
uint8_t u8[4];
} systick = { .u32 = 0 };
ISR(TIMER1_COMPA_vect)
{
systick.u32++;
}
static void uart_puttick(void)
{
uint16_t frac = TCNT1;
_uart_putch('@');
uart_puthex(systick.u8[3]);
uart_puthex(systick.u8[2]);
uart_puthex(systick.u8[1]);
uart_puthex(systick.u8[0]);
_uart_putch('.');
uart_puthex16(frac);
#if DEBUG_SP
_uart_putch('~');
uint8_t spl, sph;
asm ("\n\
in %[spl], 0x3d\n\
in %[sph], 0x3e\n\
" : [spl] "=r" (spl), [sph] "=r" (sph));
uart_puthex(sph);
uart_puthex(spl);
#endif
_uart_putch(' ');
}
static void tick_init(void)
{
TCCR1A = 0;
TCCR1B = (1 << WGM12) | (1 << CS12) | (0 << CS11) | (0 << CS10); // 8 MHz / 256 = 31250 Hz
asm volatile ("" ::: "memory");
TCNT1 = 0;
OCR1A = 31249; // 1 Hz
asm volatile ("" ::: "memory");
TIFR1 = (1 << OCF1A);
TIMSK1 = (1 << OCIE1A);
}
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