Merge pull request #4 from dhalbert/up-to-date-data

Use only latest data when reading value. Prevent sync errors.

Author: ladyada

README.rst

@@ -32,9 +32,6 @@ This is easily achieved by downloading
 
 Installing from PyPI
 =====================
-.. note:: This library is not available on PyPI yet. Install documentation is included
-   as a standard element. Stay tuned for PyPI availability!
-
 On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally `from
 PyPI <https://pypi.org/project/adafruit-circuitpython-ble-berrymed_pulse_oximeter/>`_. To install for current user:
 

adafruit_ble_berrymed_pulse_oximeter/__init__.py

@@ -33,12 +33,19 @@
 
 **Hardware:**
 
-* BM1000C, made by Shanghai Berry Electronic Tech Co.,Ltd
+* BM1000, made by Shanghai Berry Electronic Tech Co.,Ltd.
+  Device labeling is not consistent.
+  May be identified on device label, box, or in BLE advertisement as
+  BM1000, BM1000B, BM1000C, or BM1000E.
+
+  Protocol defined here:
+
+    * https://github.com/zh2x/BCI_Protocol.
 
-  Protocol defined here: https://github.com/zh2x/BCI_Protocol
   Thanks as well to:
-  * https://github.com/ehborisov/BerryMed-Pulse-Oximeter-tool
-  * https://github.com/ScheindorfHyenetics/berrymedBluetoothOxymeter
+
+    * https://github.com/ehborisov/BerryMed-Pulse-Oximeter-tool
+    * https://github.com/ScheindorfHyenetics/berrymedBluetoothOxymeter
 
 **Software and Dependencies:**
 
@@ -100,14 +107,23 @@ def values(self):
 
         Return ``None`` if no data available.
         """
-        first_byte = self.read(1)
-        # Wait for a byte with the high bit set, which indicates the beginning
-        # a data packet.
-        if not first_byte:
-            return None
-        header = first_byte[0]
-        if header & 0x80 == 0:
-            # Not synchronized.
+        # Discard stale data.
+        self.reset_input_buffer()
+        # Data packets are five bytes long. The first byte has its high bit set;
+        # the rest do not. Read up to five bytes to get back in sync.
+        have_header = False
+        for _ in range(5):
+            first_byte = self.read(1)
+            if not first_byte:
+                # Nothing read, even after stream timeout.
+                return None
+            header = first_byte[0]
+            if header & 0x80:
+                have_header = True
+                break
+
+        if not have_header:
+            # Failed to synchronize.
             return None
 
         data = self.read(4)

docs/conf.py

@@ -29,6 +29,9 @@
     "CircuitPython": ("https://circuitpython.readthedocs.io/en/latest/", None),
 }
 
+# Show the docstring from both the class and its __init__() method.
+autoclass_content = "both"
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["_templates"]