From 9d87c925a9eaa4fc256be3173c14a20d1469472d Mon Sep 17 00:00:00 2001
From: fishsoupisgood <github@madingley.org>
Date: Wed, 9 Sep 2020 11:53:37 +0100
Subject: everything, mostly, working

---
 radiator-plc/stm32/app/ticker.c | 97 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 radiator-plc/stm32/app/ticker.c

(limited to 'radiator-plc/stm32/app/ticker.c')

diff --git a/radiator-plc/stm32/app/ticker.c b/radiator-plc/stm32/app/ticker.c
new file mode 100644
index 0000000..bb346fb
--- /dev/null
+++ b/radiator-plc/stm32/app/ticker.c
@@ -0,0 +1,97 @@
+#include "project.h"
+
+static volatile uint32_t delay_ms_count;
+volatile uint32_t ticks;
+static volatile int tick_ready;
+
+uint32_t clock_scale = 72;
+
+void
+delay_us (uint32_t d)
+{
+  d *= clock_scale;
+
+  while (d--)
+    __asm__ ("nop");
+}
+
+
+
+void
+sys_tick_handler (void)
+{
+  static unsigned slow = 0;
+  static unsigned medium = 0;
+
+  if (delay_ms_count)
+    delay_ms_count--;
+
+  ticks++;
+
+  if (!tick_ready)
+    return;
+
+  //buttons_ticker();
+  //
+  led_tick();
+  usart_ticker();
+
+
+  medium++;
+
+  if (medium < 1000) return;
+
+  medium = 0;
+
+  //target_tick();
+
+  slow++;
+
+  if (slow < 2) return;
+  logic_tick();
+
+
+}
+
+
+
+void
+delay_ms (uint32_t d)
+{
+  delay_ms_count = d;
+
+  while (delay_ms_count);
+}
+
+
+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();
+
+  do {
+    clock_scale--;
+    v = ticks;
+
+    while (v == ticks);
+
+    delay_us (1000);
+    w = ticks;
+    v++;
+    w -= v;
+  } while (w);
+
+
+  tick_ready = 1;
+
+  SCS_DEMCR |= SCS_DEMCR_TRCENA;
+  SCS_DWT_CTRL |= SCS_DWT_CTRL_CYCCNTENA;
+}
-- 
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