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authorMarti Bolivar <mbolivar@leaflabs.com>2011-05-06 20:11:57 -0400
committerMarti Bolivar <mbolivar@leaflabs.com>2011-05-06 20:11:57 -0400
commitb0a0002b2e4b9dd795afc571748d91353df15fa6 (patch)
tree0ae9b3c024c9134192080179dcbde4550ea2e6c3 /libmaple/iwdg.h
parentf432df24764cee2f7d1590650eeac4f3a121f25e (diff)
downloadlibrambutan-b0a0002b2e4b9dd795afc571748d91353df15fa6.tar.gz
librambutan-b0a0002b2e4b9dd795afc571748d91353df15fa6.zip
Independent watchdog refactor.
Diffstat (limited to 'libmaple/iwdg.h')
-rw-r--r--libmaple/iwdg.h85
1 files changed, 66 insertions, 19 deletions
diff --git a/libmaple/iwdg.h b/libmaple/iwdg.h
index 4ab0ddf..81f0fdb 100644
--- a/libmaple/iwdg.h
+++ b/libmaple/iwdg.h
@@ -23,35 +23,82 @@
*****************************************************************************/
/**
- * @file iwdg.h
+ * @file iwdg.h
+ * @author Michael Hope, Marti Bolivar <mbolivar@leaflabs.com>
+ * @brief Independent watchdog support.
*
- * @brief Independent watchdog support
+ * To use the independent watchdog, first call iwdg_init() with the
+ * appropriate prescaler and IWDG counter reload values for your
+ * application. Afterwards, you must periodically call iwdg_feed()
+ * before the IWDG counter reaches 0 to reset the counter to its
+ * reload value. If you do not, the chip will reset.
+ *
+ * Once started, the independent watchdog cannot be turned off.
*/
#ifndef _IWDG_H_
#define _IWDG_H_
+#include "libmaple_types.h"
+
#ifdef __cplusplus
extern "C"{
#endif
-#define IWDG_BASE 0x40003000
-#define IWDG_KR (IWDG_BASE + 0x0)
-#define IWDG_PR (IWDG_BASE + 0x4)
-#define IWDG_RLR (IWDG_BASE + 0x8)
-#define IWDG_SR (IWDG_BASE + 0xC)
-
-enum {
- IWDG_PRE_4,
- IWDG_PRE_8,
- IWDG_PRE_16,
- IWDG_PRE_32,
- IWDG_PRE_64,
- IWDG_PRE_128,
- IWDG_PRE_256
-};
-
-void iwdg_init(uint8 prescaler, uint16 reload);
+/*
+ * Register map
+ */
+
+/** Independent watchdog register map type. */
+typedef struct iwdg_reg_map {
+ __io uint32 KR; /**< Key register. */
+ __io uint32 PR; /**< Prescaler register. */
+ __io uint32 RLR; /**< Reload register. */
+ __io uint32 SR; /**< Status register */
+} iwdg_reg_map;
+
+#define IWDG_BASE ((struct iwdg_reg_map*)0x40003000)
+
+/*
+ * Register bit definitions
+ */
+
+/* Key register */
+
+#define IWDG_KR_UNLOCK 0x5555
+#define IWDG_KR_FEED 0xAAAA
+#define IWDG_KR_START 0xCCCC
+
+/* Prescaler register */
+
+#define IWDG_PR_DIV_4 0x0
+#define IWDG_PR_DIV_8 0x1
+#define IWDG_PR_DIV_16 0x2
+#define IWDG_PR_DIV_32 0x3
+#define IWDG_PR_DIV_64 0x4
+#define IWDG_PR_DIV_128 0x5
+#define IWDG_PR_DIV_256 0x6
+
+/* Status register */
+
+#define IWDG_SR_RVU_BIT 1
+#define IWDG_SR_PVU_BIT 0
+
+#define IWDG_SR_RVU BIT(IWDG_SR_RVU_BIT)
+#define IWDG_SR_PVU BIT(IWDG_SR_PVU_BIT)
+
+/** Independent watchdog prescalers */
+typedef enum {
+ IWDG_PRE_4 = IWDG_PR_DIV_4,
+ IWDG_PRE_8 = IWDG_PR_DIV_8,
+ IWDG_PRE_16 = IWDG_PR_DIV_16,
+ IWDG_PRE_32 = IWDG_PR_DIV_32,
+ IWDG_PRE_64 = IWDG_PR_DIV_64,
+ IWDG_PRE_128 = IWDG_PR_DIV_128,
+ IWDG_PRE_256 = IWDG_PR_DIV_256
+} iwdg_prescaler;
+
+void iwdg_init(iwdg_prescaler prescaler, uint16 reload);
void iwdg_feed(void);
#ifdef __cplusplus