Merge TinyOS 2.1.1 into master.

[tinyos-2.x.git] / tos / platforms / micaz / mac / tkn154 / TKN154TimingP.nc

diff --git a/tos/platforms/micaz/mac/tkn154/TKN154TimingP.nc b/tos/platforms/micaz/mac/tkn154/TKN154TimingP.nc
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+/*
+ * Copyright (c) 2008, Technische Universitaet Berlin
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * extraification, are permitted provided that the following conditions 
+ * are met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ * - 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.
+ * - Neither the name of the Technische Universitaet Berlin 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 
+ * OWNER 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.
+ *
+ * - Revision -------------------------------------------------------------
+ * $Revision$
+ * $Date$
+ * @author: Jan Hauer <hauer@tkn.tu-berlin.de>
+ * ========================================================================
+ */
+
+/** 
+ * In slotted CSMA-CA frames must be sent on backoff boundaries (slot width:
+ * 320 us). The MicaZ platform lacks a clock with sufficient precision and
+ * accuracy, i.e. for slotted CSMA-CA the timing is *not* standard compliant
+ * (this code is experimental)
+ */
+
+#include "TKN154_platform.h"
+module TKN154TimingP
+{
+  provides interface CaptureTime;
+  provides interface ReliableWait;
+  provides interface ReferenceTime;
+  uses interface TimeCalc;
+  uses interface GetNow<bool> as CCA;
+  uses interface Alarm<T62500hz,uint32_t> as SymbolAlarm;
+  uses interface Leds;
+}
+implementation
+{
+  enum {
+    S_WAIT_OFF,
+    S_WAIT_RX,
+    S_WAIT_TX,
+    S_WAIT_BACKOFF,
+  };
+  uint8_t m_state = S_WAIT_OFF;
+
+  async command error_t CaptureTime.convert(uint16_t time, ieee154_timestamp_t *localTime, int16_t offset)
+  {
+    // Timer1 is used for capturing, it is sourced by ACLK (32768Hz),
+    // we now need to convert the capture "time" into ieee154_timestamp_t.
+    // With the 32768Hz quartz we don't have enough precision anyway,
+    // so the code below generates a timestamp that is not accurate
+    
+    uint16_t tcnt1, delta;
+    uint32_t now;
+    atomic {
+      tcnt1 = TCNT1;
+      now = call SymbolAlarm.getNow(); 
+    }
+    if (time < tcnt1)
+      delta = tcnt1 - time;
+    else
+      delta = ~(time - tcnt1) + 1;
+    *localTime = now - delta * 2 + offset; // one tick of Timer1 ~ two symbols
+    
+    return SUCCESS;
+  }
+
+  async command bool ReliableWait.ccaOnBackoffBoundary(ieee154_timestamp_t *slot0)
+  {
+    // There is no point in trying
+    return (call CCA.getNow() ? 20: 0);
+  }
+
+  async command bool CaptureTime.isValidTimestamp(uint16_t risingSFDTime, uint16_t fallingSFDTime)
+  {
+    // smallest packet (ACK) takes 
+    // length field (1) + MPDU (5) = 6 byte => 12 * 16 us = 192 us 
+    return (fallingSFDTime - risingSFDTime) > 5;
+  }
+
+  async command void ReliableWait.waitRx(uint32_t t0, uint32_t dt)
+  {
+    if (m_state != S_WAIT_OFF){
+      ASSERT(0);
+      return;
+    }
+    m_state = S_WAIT_RX;
+    call SymbolAlarm.startAt(t0 - 16, dt); // subtract 12 symbols required for Rx calibration
+  }
+
+  async command void ReliableWait.waitTx(ieee154_timestamp_t *t0, uint32_t dt)
+  {
+    if (m_state != S_WAIT_OFF){
+      ASSERT(0);
+      return;
+    }
+    m_state = S_WAIT_TX;
+    call SymbolAlarm.startAt(*t0 - 16, dt); // subtract 12 symbols required for Tx calibration
+  }
+    
+  async command void ReliableWait.waitBackoff(uint32_t dt)
+  {
+    if (m_state != S_WAIT_OFF){
+      ASSERT(0);
+      return;
+    }
+    m_state = S_WAIT_BACKOFF;
+    call SymbolAlarm.start(dt);
+  }
+
+  async event void SymbolAlarm.fired() 
+  {
+    switch (m_state)
+    {
+      case S_WAIT_RX: m_state = S_WAIT_OFF; signal ReliableWait.waitRxDone(); break;
+      case S_WAIT_TX: m_state = S_WAIT_OFF; signal ReliableWait.waitTxDone(); break;
+      case S_WAIT_BACKOFF: m_state = S_WAIT_OFF; signal ReliableWait.waitBackoffDone(); break;
+      default: ASSERT(0); break;
+    }
+  }
+
+  async command void ReferenceTime.getNow(ieee154_timestamp_t* timestamp, uint16_t dt)
+  {
+    *timestamp = call SymbolAlarm.getNow() + dt;
+  }
+
+  async command uint32_t ReferenceTime.toLocalTime(const ieee154_timestamp_t* timestamp)
+  {
+    return *timestamp;
+  } 
+
+}