AP_ADC: added new_data_available() interface

returns true if more samples are available

libraries/AP_ADC/AP_ADC.h

@@ -40,6 +40,9 @@ class AP_ADC
 	*/
 	virtual uint32_t Ch6(const uint8_t *channel_numbers, uint16_t *result) = 0;
 
+	// check if Ch6() can return new data
+	virtual bool new_data_available(const uint8_t *channel_numbers) = 0;
+
   private:
 };
 

libraries/AP_ADC/AP_ADC_ADS7844.cpp

@@ -185,6 +185,20 @@ float AP_ADC_ADS7844::Ch(uint8_t ch_num)
 	return ((float)sum)/count;
 }
 
+// see if Ch6() can return new data
+bool AP_ADC_ADS7844::new_data_available(const uint8_t *channel_numbers)
+{
+	uint8_t i;
+
+	for (i=0; i<6; i++) {
+		if (_count[channel_numbers[i]] == 0) {
+            return false;
+        }
+	}
+    return true;
+}
+
+
 // Read 6 channel values
 // this assumes that the counts for all of the 6 channels are
 // equal. This will only be true if we always consistently access a

libraries/AP_ADC/AP_ADC_ADS7844.h

@@ -29,6 +29,10 @@ class AP_ADC_ADS7844 : public AP_ADC
 
 	// Read 6 sensors at once
 	uint32_t Ch6(const uint8_t *channel_numbers, uint16_t *result);
+
+    // check if Ch6 would block
+	bool new_data_available(const uint8_t *channel_numbers);
+
 	bool	filter_result;
 
 	private:

libraries/AP_ADC/AP_ADC_HIL.cpp

@@ -82,3 +82,9 @@ void AP_ADC_HIL::setHIL(int16_t p, int16_t q, int16_t r, int16_t gyroTemp,
     // differential pressure
 	setPressure(diffPress);
 }
+
+// see if new data is available
+bool AP_ADC_HIL::new_data_available(const uint8_t *channel_numbers)
+{
+	return true;
+}

libraries/AP_ADC/AP_ADC_HIL.h

@@ -38,6 +38,9 @@ class AP_ADC_HIL : public AP_ADC
 	// Read 6 sensors at once
 	uint32_t Ch6(const uint8_t *channel_numbers, uint16_t *result);
 
+	// see if Ch6 would block
+	bool new_data_available(const uint8_t *channel_numbers);
+
 	///
 	// Set the adc raw values given the current rotations rates,
 	// temps, accels, and pressures