oprogramowanie przerwań od timera w sam7s

Witam.

Analizuje ponizszy przyklad kodu i nie moge dojsc w ktorym to miejscu ustawiany jest stan licznika od ktorego zaczyna liczyc timer? Czy moge prosic o pomoc?

#include <targets/AT91SAM7.h>

// Interrupt definitions #define AIC_SMR(n) (*(&AIC_SMR0 + n)) #define AIC_SVR(n) (*(&AIC_SVR0 + n))

#define AIC_SRCTYPE_INT_LEVEL_SENSITIVE 0x00 /* Level Sensitive */ #define AIC_SRCTYPE_INT_EDGE_TRIGGERED 0x20 /* Edge Triggered */

#define TC0_ID 12

// Timer definitions #define TC_CLKEN 0x1 #define TC_CLKDIS 0x2 #define TC_SWTRG 0x4

#define TC_CLKS 0x7 #define TC_CLKS_MCK2 0x0 #define TC_CLKS_MCK8 0x1 #define TC_CLKS_MCK32 0x2 #define TC_CLKS_MCK128 0x3 #define TC_CLKS_MCK1024 0x4

#define TC_CLKS_SLCK 0x4

#define TC_CLKS_XC0 0x5 #define TC_CLKS_XC1 0x6 #define TC_CLKS_XC2 0x7

#define TC_COVFS 0x1 /* Counter Overflow Status */ #define TC_LOVRS 0x2 /* Load Overrun Status */ #define TC_CPAS 0x4 /* RA Compare Status */ #define TC_CPBS 0x8 /* RB Compare Status */ #define TC_CPCS 0x10 /* RC Compare Status */ #define TC_LDRAS 0x20 /* RA Loading Status */ #define TC_LDRBS 0x40 /* RB Loading Status */ #define TC_ETRGS 0x80 /* External Trigger Status */ #define TC_CLKSTA 0x10000 /* Clock Status */ #define TC_MTIOA 0x20000 /* TIOA Mirror */ #define TC_MTIOB 0x40000 /* TIOB Status */

static int count;

static void ledInit(void) { PIOA_PER = 0x0000000F; PIOA_OER = 0x0000000F; }

static void ledOn(void) { PIOA_CODR = 0xF; }

static void ledOff(void) { PIOA_SODR = 0xF; }

void timer_irq_handler(void) __attribute__ ((interrupt ("IRQ")));

void timer_irq_handler(void) { TC0_SR; if (count++ & 1) ledOn(); else ledOff();

// Signal end of interrupt AIC_EOICR = 0; }

int main(void) { ledInit();

// Put LDR PC, [PC, #-0xF20] instruction into IRQ vector in order to use // hardware interrupt vectoring. *(volatile unsigned int *)0x00000018 = 0xE51FFF20;

// Set up timer interrupt __ARMLIB_enableIRQ(); AIC_IDCR = 1 << TC0_ID; AIC_SVR(TC0_ID) = (unsigned)timer_irq_handler; AIC_SMR(TC0_ID) = AIC_SRCTYPE_INT_LEVEL_SENSITIVE; AIC_ICCR = 1 << TC0_ID; AIC_IECR = 1 << TC0_ID;

// Set up timer PMC_PCER = 1 << TC0_ID; // Enable T0 peripheral clock TC0_CCR = TC_CLKDIS; TC0_IDR = 0xFFFFFFFF; TC0_CMR = TC_CLKS_MCK128; TC0_IER = TC_COVFS; TC0_CCR = TC_CLKEN | TC_SWTRG;

while (count < 5);

return 0; }