//main function
int main(void) {
char key ;
//1. system initialazation
STARTUP;
//2. initialise peripherals
init_pioa() ;
//3. initially turn led off
led_off() ;
//4. initialize timer
init_tc() ;
//5. initialize interrupt controller
init_aic() ;
tc -> Channel_0.CCR = 0x5; //6. start the timer
//7. wait until the user presses 'x'
while ( (key = getchar() != 'x'))
{}
//8. then cleanup peripherals and system
clear_aic();
clear_tc() ;
led_off() ; //9. turn off led
CLEANUP;
//and exit
return 0 ;
}
//FIQ handler
void FIQ_handler(void) {
unsigned int data_in = 0;
unsigned int fiq = 0 ;
unsigned int data_out;
fiq = aic -> IPR ; // read the IRQ source
if (fiq & (1<<PIOA_ID)) {
data_in = pioa->ISR; //clear the interrupt source of pioa
aic->ICCR = AIC(PIOA_ID); //then clears the interrupt from aic
data_in = pioa->PDSR; //read input of PDSR (line 1)
if ( data_in & 0x01 ) { //button pressed
if (button_state == BUT_IDLE) {
button_state = BUT_PRESSED;
if ( led_state == LED_IDLE ){
tc -> Channel_0.CCR = 0x5 ; // start the timer
led_state = LED_FLASHING ;
}else{
clear_tc();
led_state = LED_IDLE;
}
}
}else{
if(button_state == BUT_PRESSED)
button_state = BUT_IDLE;
}
}
if (fiq & (1<<TC0_ID)) { //if source of interrupt is 17 timer/counter 0
data_out = tc -> Channel_0.SR ; // clear timer IRQ
aic -> ICCR = (1<<TC0_ID) ; // then clear pending from aic
data_out = pioa->ODSR;
pioa->SODR = data_out & PIO(OBIT);
pioa->CODR = data_out & PIO(OBIT);
tc -> Channel_0.CCR = 0x5 ; // start the timer
}
}
//main function
int main(void) {
char key ;
STARTUP;
init_pioa() ;
init_tc() ;
init_aic() ;
while ( (key = getchar() != 'e'))
{}
clear_aic();
clear_tc() ;
CLEANUP;
//and exit
return 0 ;
}
static irqreturn_t txdtc_interrupt_handler(int irq, void *dev_id)
{
static int cycle = 0;
static char bits[10]; /* 11 send clock */
static char in_byte = 0x00;
int j=0;
clear_tc(TXD_CLOCK_CHN);
/* The data bit send cycle */
if( in_byte )
{
at91_set_gpio_value(AT91_PIN_PB4, bits[cycle]);
if(unlikely(STOP_BIT == cycle))
{
/* A byte data send over, tx_ring tail head on */
tx_ring.tail = (tx_ring.tail + 1) & (CIRC_BUF_SIZE - 1);
/* All the bit in a bytes send over */
in_byte = 0x00;
}
cycle++;
}
/* First cycle used to prepare the send data */
else if ( CIRC_CNT(tx_ring.head, tx_ring.tail, CIRC_BUF_SIZE) > 0 )
{
/* Start bit send low level*/
bits[START_BIT]=LOWLEVEL;
/* 8bits data in a byte */
for(j=0; j<8; j++)
bits[j+START_BIT+1]=(tx_ring.buf[tx_ring.tail]>>j) & 0x01;
/* Stop bit send high level*/
bits[STOP_BIT]=HIGHLEVEL;
/* Goes to next cycle start to send every bit in a bytes */
in_byte = 0x01;
cycle = START_BIT;
send_over = 0;
}
