Merge devel code into the trunk.

[tinyos-2.x.git] / tos / platforms / mica / MicaTimer.h

diff --git a/tos/platforms/mica/MicaTimer.h b/tos/platforms/mica/MicaTimer.h
new file mode 100644 (file)
index 0000000..63a6a16
--- /dev/null
+++ b/tos/platforms/mica/MicaTimer.h
@@ -0,0 +1,117 @@
+// $Id$
+/*
+ * Copyright (c) 2005-2006 Intel Corporation
+ * All rights reserved.
+ *
+ * This file is distributed under the terms in the attached INTEL-LICENSE     
+ * file. If you do not find these files, copies can be found by writing to
+ * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
+ * 94704.  Attention:  Intel License Inquiry.
+ */
+#ifndef MICATIMER_H
+#define MICATIMER_H
+
+/* This file defines the rates at which the mica family's atmega128 timer 1
+   and 3 timers run at. The goal is to present the user with microsend and
+   32khz timers, but it may not be possible to run the timers at these rates
+   (because of the limited prescaler selection).
+
+   So TinyOS picks a prescaler (based on the selected processor MHz) for
+   each of these timers, and builds corresponding 16-bit alarms&counters
+   (AlarmOne16C, AlarmThree16C, CounterOne16C, CounterThree16C) over
+   hardware timers 1 and 3. TinyOS then divides these hardware timers by
+   the appropriate power of 2 to get approximate 32-bit 32kHz and 1MHz
+   alarms and counters (Alarm32khz32C, AlarmMicro32C, Counter32khz32C,
+   CounterMicro32C).
+
+   The constants and typedefs for all this configuration are defined here,
+   based on the value of the MHZ preprocessor symbol, which shoud approximate
+   the platform's MHZ rate.
+
+   Note that the timers thus obtained will not be exactly at 32768Hz or
+   1MHz, because the clock doesn't divide by a power of two to those frequencies,
+   and/or the clock frequency is not accurate. If you need more accurate timing,
+   you should use the calibration functions offered by the Atm128Calibrate interface
+   provided by PlatformC.
+*/
+
+#include <Timer.h>
+#include <Atm128Timer.h>
+
+/* Some types for the non-standard rates that mica timers might be running
+   at.
+ */
+typedef struct { } T64khz;
+typedef struct { } T128khz;
+typedef struct { } T2mhz;
+typedef struct { } T4mhz;
+
+/* TX is the typedef for the rate of timer X, 
+   MICA_PRESCALER_X is the prescaler for timer X,
+   MICA_DIVIDER_X_FOR_Y_LOG2 is the number of bits to shift timer X by
+     to get rate Y,
+   counter_X_overflow_t is uint16_t if MICA_DIVIDER_X_FOR_Y_LOG2 is 0,
+     uint32_t otherwise.
+*/
+
+#if MHZ == 1
+typedef T128khz TOne;
+typedef TMicro TThree;
+typedef uint32_t counter_one_overflow_t;
+typedef uint16_t counter_three_overflow_t;
+
+enum {
+  MICA_PRESCALER_ONE = ATM128_CLK16_DIVIDE_8,
+  MICA_DIVIDE_ONE_FOR_32KHZ_LOG2 = 2,
+  MICA_PRESCALER_THREE = ATM128_CLK16_NORMAL,
+  MICA_DIVIDE_THREE_FOR_MICRO_LOG2 = 0
+};
+
+#elif MHZ == 2
+typedef T32khz TOne;
+typedef T2mhz TThree;
+typedef uint16_t counter_one_overflow_t;
+typedef uint32_t counter_three_overflow_t;
+
+enum {
+  MICA_PRESCALER_ONE = ATM128_CLK16_DIVIDE_64,
+  MICA_DIVIDE_ONE_FOR_32KHZ_LOG2 = 0,
+  MICA_PRESCALER_THREE = ATM128_CLK16_NORMAL,
+  MICA_DIVIDE_THREE_FOR_MICRO_LOG2 = 1
+};
+
+#elif MHZ == 4
+typedef T64khz TOne;
+typedef T4mhz TThree;
+typedef uint32_t counter_one_overflow_t;
+typedef uint32_t counter_three_overflow_t;
+
+enum {
+  MICA_PRESCALER_ONE = ATM128_CLK16_DIVIDE_64,
+  MICA_DIVIDE_ONE_FOR_32KHZ_LOG2 = 1,
+  MICA_PRESCALER_THREE = ATM128_CLK16_NORMAL,
+  MICA_DIVIDE_THREE_FOR_MICRO_LOG2 = 2
+};
+
+#elif MHZ == 8
+typedef T32khz TOne;
+typedef TMicro TThree;
+typedef uint16_t counter_one_overflow_t;
+typedef uint16_t counter_three_overflow_t;
+
+enum {
+  MICA_PRESCALER_ONE = ATM128_CLK16_DIVIDE_256,
+  MICA_DIVIDE_ONE_FOR_32KHZ_LOG2 = 0,
+  MICA_PRESCALER_THREE = ATM128_CLK16_DIVIDE_8,
+  MICA_DIVIDE_THREE_FOR_MICRO_LOG2 = 0
+};
+
+#else
+#error "Unknown clock rate. MHZ must be defined to one of 1, 2, 4, or 8."
+#endif
+
+enum {
+  PLATFORM_MHZ = MHZ
+};
+
+#endif