inital commit

1 files changed, 76 insertions, 0 deletions

diff --git a/app/ticker.c b/app/ticker.c
new file mode 100644
index 0000000..05990d2
--- /dev/null
+++ b/app/ticker.c
@@ -0,0 +1,76 @@
+#include "project.h"
+
+
+static volatile uint32_t ticks;
+static uint32_t scale = 7;
+
+unsigned led1 = 1000, led2 = 1000;
+
+
+
+void
+delay_us (uint32_t d)
+{
+  d *= scale;
+
+  while (d--) {
+    __asm__ ("nop");
+  }
+}
+
+void
+sys_tick_handler (void)
+{
+  ticks++;
+  cdcacm_tick();
+
+  if (led1) {
+    led1--;
+  }
+
+  if (led2) {
+    led2--;
+  }
+
+  if (led1) {
+    gpio_clear (LED1_BANK, LED1_GPIO);
+  } else {
+    gpio_set (LED1_BANK, LED1_GPIO);
+  }
+
+  if (led2) {
+    gpio_clear (LED2_BANK, LED2_GPIO);
+  } else {
+    gpio_set (LED2_BANK, LED2_GPIO);
+  }
+}
+
+
+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);
+}
+