1 files changed, 44 insertions, 2 deletions
diff --git a/kernel/timer.h b/kernel/timer.h
index a39d433..15488ff 100644
--- a/kernel/timer.h
+++ b/kernel/timer.h
@@ -1,6 +1,48 @@
+
+/**
+ * @file
+/// PIT /// Timer stuff // CMOS
+ http://www.brokenthorn.com/Resources/OSDevPit.html
+ https://wiki.osdev.org/CMOS
+
+ vcc/gnd - voltage/ground
+
+ D0-D7 - data lines		(data bus)
+ wr/rd - writing / reading	(system control bus) 
+ cs - ignore wr/rd or not	(address bus)
+ a0-a1				(address bus)
+
+ // the three 16bit down counters/timers/channels
+ clk	0-2 (in)
+ gate	0-2 (in)
+ out	0-2 (out)
+
+ //typical
+    out1 -> pic  interrupt on every tick (system timer)
+    out2 - was used for genearting dram memory refresh  (Do not use)
+    out3 -> pc speaker
+
+    gate pins : depend on mode of operation
+    we do have modes 0-5.
+    mode0: counts down to zero , triggers interrupt and waits 
+    mode1: 
+    mode2: rate generator (sys timer)
+    ....
+ */
+
 #include <stdint.h>
 
-void timer_init();
-void timer_tick();
+/** 
+ * Initilize time and PIT (trigger 25 times a second). 
+ * Returns the number of seconds passed since 1970.
+ */
+uint64_t timer_init();
+
+/** get number of ticks since boot */
 uint64_t timer_get_ticks();
+
+/** get number of milliseconds since boot */
 uint64_t timer_get_uptime_ms();
+
+/** get number of milliseconds since 1970 */
+uint64_t timer_get_ms();