From 069f3c54d928149a64fccd13a39789472478761e Mon Sep 17 00:00:00 2001
From: Stefan Rupp <struppi@struppi.name>
Date: Sun, 2 Mar 2014 08:01:37 +0100
Subject: [PATCH] implemented basics of rtc module

---
 rtc.c | 28 ++++++++++++++++------------
 rtc.h |  2 +-
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/rtc.c b/rtc.c
index 1147508..4f97b94 100644
--- a/rtc.c
+++ b/rtc.c
@@ -8,7 +8,6 @@
  * ----------------------------------------------------------------------------
  */
 
-#if 0
  
 #include <avr/io.h>
 #include "rtc.h"
@@ -16,24 +15,29 @@
 #include <avr/interrupt.h>
 
 
-static volatile uint32_t rtc_time;
+static volatile uint32_t _rtc_time;
 
-ISR(TIMER2_COMP_vect) {
-  ++rtc_time;
+ISR(TIMER2_OVF_vect) {
+  ++_rtc_time;
   return;
 }
 
-void rtc_init(void)
+void rtc_init(uint32_t rtc_time)
 {
   // Stop all interrupts
   cli();
+  TCCR2B = 0;
+  TCCR2A = 0;
+  TCNT2 = 0;
   // Reset timer to zero
-  rtc_time = 0;
+  _rtc_time = rtc_time;
 
-  // ...
-  // ...
-  // ...
+  ASSR = (1<<AS2); // set to asynchronous operation
+  TCCR2A = 0;
+  TCCR2B = (1<<CS22)|(1<<CS20);
   
+  TIMSK2 = (1<<TOIE2); // enable overflow interrupt
+
   sei();
 }
 
@@ -49,7 +53,7 @@ inline uint32_t rtc_get(void)
 
   sreg = SREG;
   cli();
-  t = rtc_time;
+  t = _rtc_time;
   SREG = sreg;
   return t;
 }
@@ -66,7 +70,7 @@ inline uint32_t rtc_get(void)
  * \param seconds will be filled in to contain the seconds after return
  * \param ms be filled in to contain the microseconds after return
  */
-void rtc_decode(uint32_t time, uint16_t days, uint8_t *hours, uint8_t *minutes, uint8_t *seconds)
+void rtc_decode(uint32_t time, uint16_t *days, uint8_t *hours, uint8_t *minutes, uint8_t *seconds)
 {
   if (seconds != NULL) {
     *seconds = time % 60;
@@ -131,5 +135,5 @@ void timer_validate(uint8_t *hours, uint8_t *minutes, uint8_t *seconds, uint16_t
 */
 
 #endif
-#endif
+
 
diff --git a/rtc.h b/rtc.h
index 3889fcd..56bf18d 100644
--- a/rtc.h
+++ b/rtc.h
@@ -5,6 +5,6 @@
 
 
 uint32_t rtc_get(void);
-void rtc_init(void);
+void rtc_init(uint32_t rtc_time);
 
 #endif // RTC_H