1 files changed, 76 insertions, 0 deletions
diff --git a/app/ticker.c b/app/ticker.c
new file mode 100644
index 0000000..0f7d856
--- /dev/null
+++ b/app/ticker.c
@@ -0,0 +1,76 @@
+#include "project.h"
+
+
+static volatile uint32_t delay_ms_count;
+volatile uint32_t ticks;
+static uint32_t scale=10;
+
+void
+delay_us (uint32_t d)
+{
+  d *= scale;
+  while (d--)
+    {
+      __asm__ ("nop");
+    }
+}
+
+void
+sys_tick_handler (void)
+{
+  if (delay_ms_count)
+    delay_ms_count--;
+
+  ticks++;
+}
+
+
+
+void
+delay_ms (uint32_t d)
+{
+  delay_ms_count = d;
+  while (delay_ms_count);
+}
+
+int  timed_out(uint32_t then,unsigned int ms)
+{
+then=ticks-then;
+
+if (then>ms) return 1;
+return 0;
+}
+
+
+void ticker_init(void)
+{
+  uint32_t v,w;
+
+  /*Start periodic timer*/
+
+  systick_set_clocksource (STK_CSR_CLKSOURCE_AHB_DIV8);
+  /* 48MHz / 8 = > 6Mhz */
+  systick_set_reload (6000);
+  /* 6MHz / 6000 => 1kHz */
+  systick_interrupt_enable ();
+  systick_counter_enable ();
+
+  /*Calibrate the delay loop */
+
+
+  do
+    {
+      scale--;
+      v = ticks;
+      while (v == ticks);
+      delay_us (1000);
+      w = ticks;
+      v++;
+      w -= v;
+    }
+  while (w);
+
+
+}
+
+