From de3bf162a7f3764ba43088c13e9e656c2a9ae4f1 Mon Sep 17 00:00:00 2001
From: smckown <smckown@4bc1554a-c7f2-4f65-a403-e0be01f0239c>
Date: Mon, 9 Nov 2009 19:30:52 +0000
Subject: [PATCH] Enhancements to AeroVaneReadC.

* Anemometer is read immediately after the Timer fires to reduce jitter.
* Count interface is renamed Revolutions to be more meaningful.
* m_count is now uint8_t to reflect a more reasonable real life range.
* Direction data is returned no as degrees but as a 10-bit unsigned value.
* m_sum accumulates the correct, updated angle values.
* Rounding is done properly when m_sum is negative.
---
 tos/platforms/tmirws/sensors/AeroVaneReadC.nc |  2 +-
 tos/platforms/tmirws/sensors/AeroVaneReadP.nc | 41 ++++++++++---------
 2 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/tos/platforms/tmirws/sensors/AeroVaneReadC.nc b/tos/platforms/tmirws/sensors/AeroVaneReadC.nc
index 1b2fcf2e..5ba23a9f 100644
--- a/tos/platforms/tmirws/sensors/AeroVaneReadC.nc
+++ b/tos/platforms/tmirws/sensors/AeroVaneReadC.nc
@@ -51,7 +51,7 @@ implementation {
 
   components AnemometerReadC;
   AeroVaneReadP.AnemometerControl -> AnemometerReadC.StdControl;
-  AeroVaneReadP.Count -> AnemometerReadC;
+  AeroVaneReadP.Revolutions -> AnemometerReadC;
 
   components new StateC();
   AeroVaneReadP.State -> StateC;
diff --git a/tos/platforms/tmirws/sensors/AeroVaneReadP.nc b/tos/platforms/tmirws/sensors/AeroVaneReadP.nc
index c620006e..68be7c67 100644
--- a/tos/platforms/tmirws/sensors/AeroVaneReadP.nc
+++ b/tos/platforms/tmirws/sensors/AeroVaneReadP.nc
@@ -42,7 +42,7 @@ generic module AeroVaneReadP(uint16_t period) {
     interface Timer<TMilli>;
     interface Read<uint16_t>;
     interface StdControl as AnemometerControl;
-    interface AsyncGet<uint16_t> as Count;
+    interface Get<uint16_t> as Revolutions;
     interface State;
   }
 }
@@ -54,7 +54,8 @@ implementation {
     PHYS_PER_READ = 4,		/* # of physical reads per reading */
   };
 
-  uint16_t m_count;
+  uint8_t m_count;
+  uint16_t m_speed;
   int m_vane;
   int m_sum;
 
@@ -87,6 +88,11 @@ implementation {
 
   event void Timer.fired()
   {
+    if (++m_count == PHYS_PER_READ) {
+      /* Get anemometer revolutions for the period */
+      m_speed = call Revolutions.get();
+    }
+
     if (!(call State.isIdle()))
       call Read.read();
   }
@@ -95,10 +101,10 @@ implementation {
   {
     int d = angle2 - angle1;
 
-    if (d <= -180)
-      d += 360;
-    else if (d > 180)
-      d -= 360;
+    if (d <= -512)
+      d += 1024;
+    else if (d > 512)
+      d -= 1024;
     return d;
   }
 
@@ -110,20 +116,17 @@ implementation {
       return;
 
     newVane = m_vane + distance(m_vane, result);
-    m_sum += result;
+    m_sum += m_vane;
     m_vane = newVane;
-    if (++m_count == PHYS_PER_READ) {
-      norace aerovector_t vector;
-
-      /* Get speed average */
-      atomic vector.speed = (call Count.get() * 2.25) / (period * 4 / 1024) +
-	0.5;
-
-      /* Complete direction average */
-      vector.dir = m_sum / PHYS_PER_READ;
-      while (vector.dir < 0)
-	vector.dir += 360;
-      vector.dir %= 360;
+    if (m_count == PHYS_PER_READ) {
+      aerovector_t vector;
+
+      vector.speed = m_speed;
+      if (m_sum > 0)
+	vector.dir = (m_sum + (PHYS_PER_READ / 2)) / PHYS_PER_READ;
+      else
+	vector.dir = (m_sum - (PHYS_PER_READ / 2)) / PHYS_PER_READ + 1024;
+      vector.dir &= 0x03ff; /* %= 1024 */
       init();
 
       /* Inform the consumer of the vector */
-- 
2.39.2