New Platform: TI CC2538 Development Kit

This commit adds cpu, platform and example files,
providing support for running Contiki on TI's cc2538 DK

cpu/cc2538/rtimer-arch.h

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/**
+ * \addtogroup cc2538
+ * @{
+ *
+ * \defgroup cc2538-rtimer cc2538 rtimer
+ *
+ * Implementation of the rtimer module for the cc2538
+ *
+ * The rtimer runs on the Sleep Timer. This is a design choice, as many parts
+ * of Contiki like rtimers with a value of RTIMER_ARCH_SECOND being a power of
+ * two. The ST runs on the 32kHz clock, which can provide us with an excellent
+ * value of 32768 for RTIMER_ARCH_SECOND.
+ *
+ * Additionally, since the ST keeps running in PM2, we can do things like drop
+ * to PM2 and schedule a wake-up time through the rtimer API.
+ *
+ * \note If the 32kHz clock is running on the 32kHz RC OSC, the rtimer is
+ * not 100% accurate (the RC OSC does not run at exactly 32.768 kHz). For
+ * applications requiring higher accuracy, the 32kHz clock should be changed to
+ * use the XOSC as its source. To see which low-frequency OSC the 32kHz clock
+ * is running on, see cpu/cc2538/clock.c.
+ *
+ * \sa cpu/cc2538/clock.c
+ * @{
+ */
+/**
+ * \file
+ * Header file for the cc2538 rtimer driver
+ */
+#ifndef RTIMER_ARCH_H_
+#define RTIMER_ARCH_H_
+
+#include "contiki.h"
+#include "dev/gptimer.h"
+
+#define RTIMER_ARCH_SECOND 32768
+
+/** \sa RTIMER_NOW() */
+rtimer_clock_t rtimer_arch_now(void);
+
+/**
+ * \brief Get the time of the next scheduled rtimer trigger
+ * \return The time next rtimer ISR is scheduled for
+ */
+rtimer_clock_t rtimer_arch_next_trigger(void);
+
+#endif /* RTIMER_ARCH_H_ */
+
+/**
+ * @}
+ * @}
+ */