increase default ADC conversion rate; update example

Increased the default ADC conversion rate from 10 to 20 samples per second to eliminate a racing error where the conversion completion (Cycle Ready) flag wasn't consistently set. The error made it appear that the ADC data wasn't available. Successfully tested conversion rates up to 320 sps. Note: high sample rates are inherently less accurate but may be useful for some applications.

Fixed an error in the simpletest example was causing the example to continuously read the ADC data, ignoring the conversion completion (Cycle Ready) flag.

Both changes are expected to be transparent to all existing applications.

Thank you to @Swicano for discovering the issue in `simpletest` that revealed the timing problem.

Author: CedarGroveStudios

examples/clue_scale_calibrator.py

@@ -35,7 +35,7 @@ def read(samples=100):
     sample_sum = 0
     sample_count = samples
     while sample_count > 0:
-        if nau7802.available:
+        if nau7802.available():
             sample_sum = sample_sum + nau7802.read()
             sample_count -= 1
     return int(sample_sum / samples)

examples/clue_scale_code.py

@@ -131,7 +131,7 @@ def read(samples=100):
     sample_sum = 0
     sample_count = samples
     while sample_count > 0:
-        if nau7802.available:
+        if nau7802.available():
             sample_sum = sample_sum + nau7802.read()
             sample_count -= 1
     return int(sample_sum / samples)

examples/dual_clue_scale_calibrator.py

@@ -35,7 +35,7 @@ def read(samples=100):
     sample_sum = 0
     sample_count = samples
     while sample_count > 0:
-        if nau7802.available:
+        if nau7802.available():
             sample_sum = sample_sum + nau7802.read()
             sample_count -= 1
     return int(sample_sum / samples)

examples/dual_clue_scale_code.py

@@ -137,7 +137,7 @@ def read(samples=100):
     sample_sum = 0
     sample_count = samples
     while sample_count > 0:
-        if nau7802.available:
+        if nau7802.available():
             sample_sum = sample_sum + nau7802.read()
             sample_count -= 1
     return int(sample_sum / samples)

examples/dual_clue_scale_mux_calibrator.py

@@ -45,11 +45,11 @@ def read(sensor=1, samples=100):
     sample_count = samples
     while sample_count > 0:
         if sensor == 1:
-            if nau7802_1.available:
+            if nau7802_1.available():
                 sample_sum = sample_sum + nau7802_1.read()
                 sample_count -= 1
         elif sensor == 2:
-            if nau7802_2.available:
+            if nau7802_2.available():
                 sample_sum = sample_sum + nau7802_2.read()
                 sample_count -= 1
     return int(sample_sum / samples)

examples/dual_clue_scale_mux_code.py

@@ -147,11 +147,11 @@ def read(sensor=1, samples=100):
     sample_count = samples
     while sample_count > 0:
         if sensor == 1:
-            if nau7802_1.available:
+            if nau7802_1.available():
                 sample_sum = sample_sum + nau7802_1.read()
                 sample_count -= 1
         elif sensor == 2:
-            if nau7802_2.available:
+            if nau7802_2.available():
                 sample_sum = sample_sum + nau7802_2.read()
                 sample_count -= 1
     return int(sample_sum / samples)

examples/nau7802_simpletest.py

@@ -62,11 +62,9 @@ def read_raw_value(samples=100):
 while True:
     print("=====")
     nau7802.channel = 1
-    if nau7802.available():
-        value = read_raw_value()
-        print("channel %1.0f raw value: %7.0f" % (nau7802.channel, value))
+    value = read_raw_value()
+    print("channel %1.0f raw value: %7.0f" % (nau7802.channel, value))
 
     nau7802.channel = 2
-    if nau7802.available():
-        value = read_raw_value()
-        print("channel %1.0f raw value: %7.0f" % (nau7802.channel, value))
+    value = read_raw_value()
+    print("channel %1.0f raw value: %7.0f" % (nau7802.channel, value))