From ee5667f54d76022beec4584ccf50879c68361a33 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@mit.edu>
Date: Mon, 13 Sep 2010 13:32:01 -0400
Subject: bugfix MAPLE_RELOAD_VAL, whitespace fixes

---
 wirish/boards.h | 8 ++++----
 wirish/time.c   | 2 +-
 wirish/time.h   | 7 +++++--
 3 files changed, 10 insertions(+), 7 deletions(-)

(limited to 'wirish')

diff --git a/wirish/boards.h b/wirish/boards.h
index 617a7ad..03d0b0e 100644
--- a/wirish/boards.h
+++ b/wirish/boards.h
@@ -72,10 +72,10 @@ typedef struct ExtiInfo {
 } ExtiInfo;
 
 // LeafLabs Maple rev3, rev4
-#ifdef BOARD_maple  
+#ifdef BOARD_maple
 
     #define CYCLES_PER_MICROSECOND  72
-    #define MAPLE_RELOAD_VAL        72000
+    #define MAPLE_RELOAD_VAL        71999 /* takes a cycle to reload */
 
     static __attribute__ ((unused)) PinMapping PIN_MAP[NR_GPIO_PINS] = {
         {GPIOA_BASE,  3,        ADC3, TIMER2_CH4_CCR}, // D0/PA3
@@ -142,10 +142,10 @@ typedef struct ExtiInfo {
 #endif
 
 // LeafLabs Maple Native (prototype)
-#ifdef BOARD_maple_native  
+#ifdef BOARD_maple_native
 
     #define CYCLES_PER_MICROSECOND  72
-    #define MAPLE_RELOAD_VAL        72000
+    #define MAPLE_RELOAD_VAL        71999 /* takes a cycle to reload */
 
     // TODO:
     static __attribute__ ((unused)) PinMapping PIN_MAP[NR_GPIO_PINS] = {
diff --git a/wirish/time.c b/wirish/time.c
index ea8ebe1..eaa3c9e 100644
--- a/wirish/time.c
+++ b/wirish/time.c
@@ -23,7 +23,7 @@
  * ****************************************************************************/
 
 /**
- *  @brief 
+ *  @brief
  */
 
 #include "libmaple.h"
diff --git a/wirish/time.h b/wirish/time.h
index f73d133..ad39057 100644
--- a/wirish/time.h
+++ b/wirish/time.h
@@ -23,7 +23,7 @@
  * ****************************************************************************/
 
 /**
- *  @brief 
+ *  @brief
  */
 
 #ifndef _TIME_H
@@ -59,7 +59,10 @@ static inline uint32 micros(void) {
 
    nvic_globalirq_enable();
 
-   res = (ms * US_PER_MS) + (MAPLE_RELOAD_VAL - cycle_cnt)/CYCLES_PER_MICROSECOND;
+   /* MAPLE_RELOAD_VAL is 1 less than the number of cycles it actually
+      takes to complete a systick reload */
+   res = (ms * US_PER_MS) +
+       (MAPLE_RELOAD_VAL + 1 - cycle_cnt)/CYCLES_PER_MICROSECOND;
 
    return res;
 }
-- 
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