1 files changed, 74 insertions, 0 deletions
diff --git a/stm32/app/ticker.c b/stm32/app/ticker.c
new file mode 100644
index 0000000..f124307
--- /dev/null
+++ b/stm32/app/ticker.c
@@ -0,0 +1,74 @@
+#include "project.h"
+
+
+volatile uint32_t ticks;
+static uint32_t scale = 7;
+
+unsigned  led2 = 1000;
+
+
+
+void
+delay_us (uint32_t d)
+{
+  d *= scale;
+
+  while (d--)
+    __asm__ ("nop");
+}
+
+void
+sys_tick_handler (void)
+{
+  ticks++;
+  cdcacm_tick();
+  hands_tick();
+  motor_tick();
+
+  if (led2)
+    led2--;
+
+  if (led2)
+    CLEAR (LED2);
+
+  else
+    SET (LED2);
+}
+
+void
+ticker_init (void)
+{
+  uint32_t v, w;
+  /*Start periodic timer */
+  systick_set_clocksource (STK_CSR_CLKSOURCE_AHB_DIV8);
+  /* 72MHz / 8 = > 9Mhz */
+  systick_set_reload (9000);
+  /* 9MHz / 9000 => 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);
+
+}
+
+
+void delay_ms (uint32_t d)
+{
+  uint32_t v = ticks;
+
+  while ((ticks - v) < d);
+}
+
+