Make changes to support binary transfers.

Makefile

@@ -29,7 +29,7 @@ flake8:
 	# F403 'from module import *' used; unable to detect undefined names  https://www.flake8rules.com/rules/F403.html
 	# W503 Line break occurred before a binary operator https://www.flake8rules.com/rules/W503.html
 	# E501 Line too long (>79 characters) https://www.flake8rules.com/rules/E501.html
-	${PYTHON} -m flake8 test/ notecard/ examples/ mpy_board/ --count --ignore=E722,F401,F403,W503,E501 --show-source --statistics
+	${PYTHON} -m flake8 test/ notecard/ examples/ mpy_board/ --count --ignore=E722,F401,F403,W503,E501,E502 --show-source --statistics
 
 coverage:
 	${RUN_VENV_ACTIVATE}

examples/notecard-basics/cpy_example.py

@@ -14,20 +14,6 @@
 import busio  # noqa: E402
 
 
-def NotecardExceptionInfo(exception):
-    """Construct a formatted Exception string.
-
-    Args:
-        exception (Exception): An exception object.
-
-    Returns:
-        string: a summary of the exception with line number and details.
-    """
-    name = exception.__class__.__name__
-    return sys.platform + ": " + name \
-        + ": " + " ".join(map(str, exception.args))
-
-
 def configure_notecard(card, product_uid):
     """Submit a simple JSON-based request to the Notecard.
 
@@ -39,11 +25,7 @@ def configure_notecard(card, product_uid):
     req["product"] = product_uid
     req["mode"] = "continuous"
 
-    try:
-        card.Transaction(req)
-    except Exception as exception:
-        print("Transaction error: " + NotecardExceptionInfo(exception))
-        time.sleep(5)
+    card.Transaction(req)
 
 
 def get_temp_and_voltage(card):
@@ -53,20 +35,13 @@ def get_temp_and_voltage(card):
         card (object): An instance of the Notecard class
 
     """
-    temp = 0
-    voltage = 0
-
-    try:
-        req = {"req": "card.temp"}
-        rsp = card.Transaction(req)
-        temp = rsp["value"]
+    req = {"req": "card.temp"}
+    rsp = card.Transaction(req)
+    temp = rsp["value"]
 
-        req = {"req": "card.voltage"}
-        rsp = card.Transaction(req)
-        voltage = rsp["value"]
-    except Exception as exception:
-        print("Transaction error: " + NotecardExceptionInfo(exception))
-        time.sleep(5)
+    req = {"req": "card.voltage"}
+    rsp = card.Transaction(req)
+    voltage = rsp["value"]
 
     return temp, voltage
 
@@ -75,7 +50,8 @@ def run_example(product_uid, use_uart=True):
     """Connect to Notcard and run a transaction test."""
     print("Opening port...")
     if use_uart:
-        port = busio.UART(board.TX, board.RX, baudrate=9600)
+        port = busio.UART(board.TX, board.RX, baudrate=9600,
+                          receiver_buffer_size=128)
     else:
         port = busio.I2C(board.SCL, board.SDA)
 

examples/notecard-basics/mpy_example.py

@@ -16,20 +16,6 @@
 from machine import Pin
 
 
-def NotecardExceptionInfo(exception):
-    """Construct a formatted Exception string.
-
-    Args:
-        exception (Exception): An exception object.
-
-    Returns:
-        string: a summary of the exception with line number and details.
-    """
-    name = exception.__class__.__name__
-    return sys.platform + ": " + name + ": " \
-        + " ".join(map(str, exception.args))
-
-
 def configure_notecard(card, product_uid):
     """Submit a simple JSON-based request to the Notecard.
 
@@ -41,11 +27,7 @@ def configure_notecard(card, product_uid):
     req["product"] = product_uid
     req["mode"] = "continuous"
 
-    try:
-        card.Transaction(req)
-    except Exception as exception:
-        print("Transaction error: " + NotecardExceptionInfo(exception))
-        time.sleep(5)
+    card.Transaction(req)
 
 
 def get_temp_and_voltage(card):
@@ -55,20 +37,13 @@ def get_temp_and_voltage(card):
         card (object): An instance of the Notecard class
 
     """
-    temp = 0
-    voltage = 0
-
-    try:
-        req = {"req": "card.temp"}
-        rsp = card.Transaction(req)
-        temp = rsp["value"]
-
-        req = {"req": "card.voltage"}
-        rsp = card.Transaction(req)
-        voltage = rsp["value"]
-    except Exception as exception:
-        print("Transaction error: " + NotecardExceptionInfo(exception))
-        time.sleep(5)
+    req = {"req": "card.temp"}
+    rsp = card.Transaction(req)
+    temp = rsp["value"]
+
+    req = {"req": "card.voltage"}
+    rsp = card.Transaction(req)
+    voltage = rsp["value"]
 
     return temp, voltage
 

notecard/crc32.py

@@ -0,0 +1,33 @@
+"""Module for computing the CRC32 of arbitrary data."""
+
+crc32_lookup_table = [
+    0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC, 0x76DC4190, 0x6B6B51F4,
+    0x4DB26158, 0x5005713C, 0xEDB88320, 0xF00F9344, 0xD6D6A3E8, 0xCB61B38C,
+    0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, 0xBDBDF21C
+]
+
+
+def _logical_rshift(val, shift_amount, num_bits=32):
+    """Logcally right shift `val` by `shift_amount` bits.
+
+    Logical right shift (i.e. right shift that fills with 0s instead of the
+    sign bit) isn't supported natively in Python. This is a simple
+    implementation. See:
+    https://realpython.com/python-bitwise-operators/#arithmetic-vs-logical-shift
+    """
+    unsigned_val = val % (1 << num_bits)
+    return unsigned_val >> shift_amount
+
+
+def crc32(data):
+    """Compute CRC32 of the given data.
+
+    Small lookup-table half-byte CRC32 algorithm based on:
+    https://create.stephan-brumme.com/crc32/#half-byte
+    """
+    crc = ~0
+    for idx in range(len(data)):
+        crc = crc32_lookup_table[(crc ^ data[idx]) & 0x0F] ^ _logical_rshift(crc, 4)
+        crc = crc32_lookup_table[(crc ^ _logical_rshift(data[idx], 4)) & 0x0F] ^ _logical_rshift(crc, 4)
+
+    return ~crc & 0xffffffff