From b835b9864d7fa17de8eeaaafbb1b17f2252e68a5 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@leaflabs.com>
Date: Fri, 1 Apr 2011 03:15:27 -0400
Subject: SysTick refactor.

For the changelog:

* util.h is free of __read(), __write(), etc. macros.

* systick_resume() was renamed systick_enable().
---
 libmaple/systick.h | 46 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 38 insertions(+), 8 deletions(-)

(limited to 'libmaple/systick.h')

diff --git a/libmaple/systick.h b/libmaple/systick.h
index 33a3cf8..35b4cb9 100644
--- a/libmaple/systick.h
+++ b/libmaple/systick.h
@@ -31,30 +31,60 @@
 #ifndef _SYSTICK_H_
 #define _SYSTICK_H_
 
-#include "libmaple.h"
+#include "libmaple_types.h"
+#include "util.h"
 
 #ifdef __cplusplus
 extern "C"{
 #endif
 
-#define SYSTICK_CSR             0xE000E010  // Control and status register
-#define SYSTICK_CNT             0xE000E018  // Current value register
+/** SysTick register map type */
+typedef struct systick_reg_map {
+    __io uint32 CSR;            /**< Control and status register */
+    __io uint32 RVR;            /**< Reload value register */
+    __io uint32 CNT;            /**< Current value register ("count") */
+    __io uint32 CVR;            /**< Calibration value register */
+} systick_reg_map;
 
-#define SYSTICK_CSR_COUNTFLAG   BIT(16)
+/** SysTick register map base pointer */
+#define SYSTICK_BASE                    ((struct systick_reg_map*)0xE000E010)
 
-/** System elapsed time in milliseconds */
+/*
+ * Register bit definitions.
+ */
+
+/* Control and status register */
+
+#define SYSTICK_CSR_COUNTFLAG           BIT(16)
+#define SYSTICK_CSR_CLKSOURCE           BIT(2)
+#define SYSTICK_CSR_CLKSOURCE_EXTERNAL  0
+#define SYSTICK_CSR_CLKSOURCE_CORE      BIT(2)
+#define SYSTICK_CSR_TICKINT             BIT(1)
+#define SYSTICK_CSR_TICKINT_PEND        BIT(1)
+#define SYSTICK_CSR_TICKINT_NO_PEND     0
+#define SYSTICK_CSR_ENABLE              BIT(0)
+#define SYSTICK_CSR_ENABLE_MULTISHOT    BIT(0)
+#define SYSTICK_CSR_ENABLE_DISABLED     0
+
+/* Calibration value register */
+
+#define SYSTICK_CVR_NOREF               BIT(31)
+#define SYSTICK_CVR_SKEW                BIT(30)
+#define SYSTICK_CVR_TENMS               0xFFFFFF
+
+/** System elapsed time, in milliseconds */
 extern volatile uint32 systick_timer_millis;
 
 void systick_init(uint32 reload_val);
 void systick_disable();
-void systick_resume();
+void systick_enable();
 
 static inline uint32 systick_get_count(void) {
-    return __read(SYSTICK_CNT);
+    return SYSTICK_BASE->CNT;
 }
 
 static inline uint32 systick_check_underflow(void) {
-    return (__read(SYSTICK_CSR) & SYSTICK_CSR_COUNTFLAG);
+    return SYSTICK_BASE->CSR & SYSTICK_CSR_COUNTFLAG;
 }
 
 #ifdef __cplusplus
-- 
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