1 files changed, 37 insertions, 0 deletions
diff --git a/src/lib/systick.h b/src/lib/systick.h
new file mode 100644
index 0000000..42d33d0
--- /dev/null
+++ b/src/lib/systick.h
@@ -0,0 +1,37 @@
+#ifndef _SYSTICK_H_
+#define _SYSTICK_H_
+#include <inttypes.h>
+#include "util.h"
+
+/* To the ARM technical manual... there's nearly nothing on the systick
+ * timer in the stm32 manual */
+
+#define SYSTICK_CSR       *(volatile int*)0xE000E010  // Control and status register
+#define SYSTICK_RELOAD    *(volatile int*)0xE000E014  // Reload value register
+#define SYSTICK_CNT       *(volatile int*)0xE000E018  // Current value register
+#define SYSTICK_CALIB     *(volatile int*)0xE000E01C  // Calibration value register
+
+#define SYSTICK_SRC_HCLK  BIT(2)    // Use core clock
+#define SYSTICK_TICKINT   BIT(1)    // Interrupt on systick countdown
+#define SYSTICK_ENABLE    BIT(0)    // Turn on the counter
+
+/* We use the systick timer to tick once
+ * every millisecond */
+#define MAPLE_RELOAD_VAL     72000
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void systick_init(void);
+
+static inline uint32_t systick_get_count(void) {
+    return (uint32_t)SYSTICK_CNT;
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif
+