From 5a3645d36a93d2d3321ab1869aecc4b4bc81dbe1 Mon Sep 17 00:00:00 2001
From: rmackay9 <rmackay9@yahoo.com>
Date: Thu, 30 Aug 2012 16:50:03 +0900
Subject: [PATCH] AP_ADC: added num_samples_available to allow main loop to be
 synced with arrival of new sensor data for Oilpan.

---
 libraries/AP_ADC/AP_ADC.h           |  2 ++
 libraries/AP_ADC/AP_ADC_ADS7844.cpp | 15 +++++++++++++++
 libraries/AP_ADC/AP_ADC_ADS7844.h   |  3 +++
 libraries/AP_ADC/AP_ADC_HIL.cpp     |  6 ++++++
 libraries/AP_ADC/AP_ADC_HIL.h       |  3 +++
 5 files changed, 29 insertions(+)

diff --git a/libraries/AP_ADC/AP_ADC.h b/libraries/AP_ADC/AP_ADC.h
index 0a257e3263..7a09ebf557 100644
--- a/libraries/AP_ADC/AP_ADC.h
+++ b/libraries/AP_ADC/AP_ADC.h
@@ -44,6 +44,8 @@ public:
     // check if Ch6() can return new data
     virtual bool            new_data_available(const uint8_t *channel_numbers) = 0;
 
+    virtual uint16_t        num_samples_available(const uint8_t *channel_numbers) = 0;
+
 private:
 };
 
diff --git a/libraries/AP_ADC/AP_ADC_ADS7844.cpp b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
index 01c13e7a9d..dfb8780798 100644
--- a/libraries/AP_ADC/AP_ADC_ADS7844.cpp
+++ b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
@@ -246,3 +246,18 @@ uint32_t AP_ADC_ADS7844::Ch6(const uint8_t *channel_numbers, float *result)
     // return number of microseconds since last call
     return ret;
 }
+
+/// Get minimum number of samples read from the sensors
+uint16_t AP_ADC_ADS7844::num_samples_available(const uint8_t *channel_numbers)
+{
+    // get count of first channel as a base
+    uint16_t min_count = _count[channel_numbers[0]];
+
+    // reduce to minimum count of all other channels
+    for (uint8_t i=1; i<6; i++) {
+        if (_count[channel_numbers[i]] < min_count) {
+            min_count = _count[channel_numbers[i]];
+        }
+    }
+    return min_count;
+}
diff --git a/libraries/AP_ADC/AP_ADC_ADS7844.h b/libraries/AP_ADC/AP_ADC_ADS7844.h
index 66098a7994..71452161f4 100644
--- a/libraries/AP_ADC/AP_ADC_ADS7844.h
+++ b/libraries/AP_ADC/AP_ADC_ADS7844.h
@@ -33,6 +33,9 @@ public:
     // check if Ch6 would block
     bool                new_data_available(const uint8_t *channel_numbers);
 
+    // Get minimum number of samples read from the sensors
+    uint16_t            num_samples_available(const uint8_t *channel_numbers);
+
 private:
     static void         read(uint32_t);
 
diff --git a/libraries/AP_ADC/AP_ADC_HIL.cpp b/libraries/AP_ADC/AP_ADC_HIL.cpp
index 2cf0811157..5ea1efaba1 100644
--- a/libraries/AP_ADC/AP_ADC_HIL.cpp
+++ b/libraries/AP_ADC/AP_ADC_HIL.cpp
@@ -88,3 +88,9 @@ bool AP_ADC_HIL::new_data_available(const uint8_t *channel_numbers)
 {
     return true;
 }
+
+// Get minimum number of samples read from the sensors
+uint16_t AP_ADC_HIL::num_samples_available(const uint8_t *channel_numbers)
+{
+    return 1;
+}
\ No newline at end of file
diff --git a/libraries/AP_ADC/AP_ADC_HIL.h b/libraries/AP_ADC/AP_ADC_HIL.h
index 22502359c9..b44147e891 100644
--- a/libraries/AP_ADC/AP_ADC_HIL.h
+++ b/libraries/AP_ADC/AP_ADC_HIL.h
@@ -41,6 +41,9 @@ public:
     // see if Ch6 would block
     bool            new_data_available(const uint8_t *channel_numbers);
 
+    // Get minimum number of samples read from the sensors
+    uint16_t        num_samples_available(const uint8_t *channel_numbers);
+
     ///
     // Set the adc raw values given the current rotations rates,
     // temps, accels, and pressures