Added sources of demo application by Milan Navratil

[mirosot.git] / navratil_ad / timer3.c

diff --git a/navratil_ad/timer3.c b/navratil_ad/timer3.c
new file mode 100644 (file)
index 0000000..a531deb
--- /dev/null
+++ b/navratil_ad/timer3.c
@@ -0,0 +1,57 @@
+#include <timer3.h>
+#include <mcu_regs.h>
+#include <cpu_def.h>
+#include <system_def.h>
+
+static volatile timer_t timer;
+
+static void  timer_isr(void) __attribute__ ((interrupt_handler));
+
+static void 
+timer_isr(void)
+{
+    timer++;
+    //*TPU_TSR3 &= ~TSR2_TCFVm ; //reset overflow flag (clear interrupt)
+    *TPU_TSR3 &= ~TSR3_TCFVm & ~TSR3_TGFAm; //reset overflow and comare match flags
+}    
+
+//timer initialisation
+/*free running counter*/
+int init_timer3(long long nsec)
+{
+#define CPU_CYCLE_NSEC (1000000000/CPU_SYS_HZ)
+  long long timer_tick = CPU_CYCLE_NSEC;
+  int presc_ind = 0;
+  const signed char presc_tab[] = {0,1,2,3,6,5,7,-1};
+  long long nsec_scaled = nsec >> 16;
+  while (presc_ind < 8 &&
+         (timer_tick < nsec_scaled
+          || presc_tab[presc_ind] < 0)) {
+    presc_ind++;
+    timer_tick <<= 2;
+  }
+  if (timer_tick < nsec_scaled)
+    return -1;
+
+
+  *SYS_MSTPCRA &= ~MSTPCRA_TPUm; // power TPU unit
+  
+  *TPU_TCR3 = TCR3_CCLR0m | presc_tab[presc_ind]; //rising edge, cleared by TGA, prescaler is calculated
+  *TPU_TMDR3 =0x00;             // normal mode
+  *TPU_TIOR3L = TIOR3L_IOC1m;   // output 1 at compare match
+  *TPU_TSR3 &= ~TSR3_TCFVm & ~TSR3_TGFAm; //reset overflow and comare match flags
+  //*TPU_TIER3 |=TIER3_TCIEVm;    //enable overflow interrupt
+  *TPU_TIER3 |=TIER3_TGIEAm;    //enable compare match interrupt
+  *TPU_TGR3A = (unsigned)(nsec/timer_tick);
+
+  *TPU_TSTR |=TSTR_CST3m;       //start timer
+  
+  //excptvec_set(EXCPTVEC_TCI3V, timer_isr);  /* handle overflow interrupt */
+  excptvec_set(EXCPTVEC_TGI3A, timer_isr); /* handle TGRA match interrupt */
+  return 0;
+}
+
+timer_t get_timer()
+{
+  return timer;
+}