app/shodiny/hodiny.c

   1 /* ustredni hodiny Spejbla */
   2
   3 #include <types.h>
   4 #include <lpc21xx.h>
   5 #include <periph/can.h>
   6
   7 #define CANLOAD_ID (*((volatile unsigned long *) 0x40000120))
   8
   9 void timer_irq() __attribute__((interrupt));
  10
  11 void timer_init(uint32_t prescale, uint32_t period) {
  12   T0PR = prescale - 1;
  13   T0MR1 = period - 1;
  14   T0MCR = 0x3<<3; /* interrupt and counter reset on match1 */
  15   T0EMR = 0x1<<6 | 0x2; /* set MAT0.1 low on match and high now */
  16   T0CCR = 0x0; /* no capture */
  17   T0TCR |= 0x1; /* go! */
  18 }
  19
  20 void timer_init_irq(unsigned irq_vect) {
  21   /* set interrupt vector */
  22   ((uint32_t*)&VICVectAddr0)[irq_vect] = (uint32_t)timer_irq;
  23   ((uint32_t*)&VICVectCntl0)[irq_vect] = 0x20 | 4;
  24   /* enable timer int */
  25   VICIntEnable = 0x00000010;
  26 }
  27
  28 can_msg_t msg = {.flags = 0, .dlc = 1};
  29 uint8_t seq_num = 0;
  30
  31 void timer_irq() {
  32   msg.data[0] = seq_num++;
  33   while (can_tx_msg(&msg));
  34   /* clear int flag */
  35   T0IR = 0xffffffff;
  36   /* int acknowledge */
  37   VICVectAddr = 0;
  38 }
  39
  40 int main() {
  41   /* peripheral clock = CPU clock (10MHz) */
  42   VPBDIV = 1;
  43   /** map exception handling to RAM **/
  44   MEMMAP = 0x2;
  45   /* init Vector Interrupt Controller */
  46   VICIntEnClr = 0xFFFFFFFF;
  47   VICIntSelect = 0x00000000;
  48   /* 10MHz VPB, 1000kb/s TSEG1=6, TSEG2=3, SJW= */
  49   can_init(0x250000, 14, NULL);
  50   msg.id = CANLOAD_ID;
  51   /* * */
  52   timer_init(10, 4000 /*250Hz*/);
  53   timer_init_irq(13);
  54   /* jamais fatigue */
  55   for (;;);
  56 }