a little refactoring, speed-up, and CPython compatibility

adafruit_vc0706.py

@@ -42,7 +42,6 @@
 * Adafruit CircuitPython firmware for the ESP8622 and M0-based boards:
   https://github.com/adafruit/circuitpython/releases
 """
-import busio
 from micropython import const
 
 __version__ = "0.0.0-auto.0"
@@ -79,6 +78,11 @@
 IMAGE_SIZE_320x240              = const(0x11)
 IMAGE_SIZE_160x120              = const(0x22)
 # pylint: enable=invalid-name
+_BAUDRATE_9600                   = const(0xAEC8)
+_BAUDRATE_19200                  = const(0x56E4)
+_BAUDRATE_38400                  = const(0x2AF2)
+_BAUDRATE_57600                  = const(0x1C1C)
+_BAUDRATE_115200                 = const(0x0DA6)
 
 _MOTIONCONTROL        = const(0x0)
 _UARTMOTION           = const(0x01)
@@ -93,20 +97,19 @@
 
 class VC0706:
     """Driver for VC0706 serial TTL camera module.
-
-       :param ~microcontroller.Pin rx: Receive pin
-       :param ~microcontroller.Pin tx: Transmit pin
-       :param int baudrate: Serial connection speed
-       :param int timeout: Read timeout in seconds
-       :param int buffer_size: Receive buffer size
     """
-    def __init__(self, rx, tx, *, baudrate=38400, timeout=250, buffer_size=100):
-        self._uart = busio.UART(tx, rx, baudrate=baudrate, timeout=timeout)
+    def __init__(self, uart, *, buffer_size=100):
+        self._uart = uart
         self._buffer = bytearray(buffer_size)
         self._frame_ptr = 0
         self._command_header = bytearray(3)
-        if not self._run_command(_RESET, bytes([0x00]), 5):
-            raise RuntimeError('Failed to get response from VC0706, check wiring!')
+        for _ in range(2): # 2 retries to reset then check resetted baudrate
+            for baud in (9600, 19200, 38400, 57600, 115200):
+                self._uart.baudrate = baud
+                if self._run_command(_RESET, bytes([0x00]), 5):
+                    break
+            else: # for:else rocks! http://book.pythontips.com/en/latest/for_-_else.html
+                raise RuntimeError('Failed to get response from VC0706, check wiring!')
 
     @property
     def version(self):
@@ -116,6 +119,32 @@ def version(self):
         readlen = self._read_response(self._buffer, len(self._buffer))
         return str(self._buffer[:readlen], 'ascii')
 
+    @property
+    def baudrate(self):
+        """Return the currently configured baud rate."""
+        return self._uart.baudrate
+
+    @baudrate.setter
+    def baudrate(self, baud):
+        """Set the baudrate to 9600, 19200, 38400, 57600, or 115200. """
+        divider = None
+        if baud == 9600:
+            divider = _BAUDRATE_9600
+        elif baud == 19200:
+            divider = _BAUDRATE_19200
+        elif baud == 38400:
+            divider = _BAUDRATE_38400
+        elif baud == 57600:
+            divider = _BAUDRATE_57600
+        elif baud == 115200:
+            divider = _BAUDRATE_115200
+        else:
+            raise ValueError("Unsupported baud rate")
+        args = [0x03, 0x01, (divider>>8) & 0xFF, divider & 0xFF]
+        self._run_command(_SET_PORT, bytes(args), 7)
+        print([hex(i) for i in self._buffer[0:10]])
+        self._uart.baudrate = baud
+
     @property
     def image_size(self):
         """Get the current image size, will return a value of IMAGE_SIZE_640x480,
@@ -172,7 +201,7 @@ def read_picture_into(self, buf):
         args = bytes([0x0C, 0x0, 0x0A, 0, 0, (self._frame_ptr >> 8) & 0xFF,
                       self._frame_ptr & 0xFF, 0, 0, 0, n & 0xFF,
                       (_CAMERA_DELAY >> 8) & 0xFF, _CAMERA_DELAY & 0xFF])
-        if not self._run_command(_READ_FBUF, args, 5):
+        if not self._run_command(_READ_FBUF, args, 5, flush=False):
             return 0
         if self._read_response(self._buffer, n+5) == 0:
             return 0
@@ -192,7 +221,7 @@ def _run_command(self, cmd, args, resplen, flush=True):
         return True
 
     def _read_response(self, result, numbytes):
-        return self._uart.readinto(result, numbytes)
+        return self._uart.readinto(memoryview(result)[0:numbytes])
 
     def _verify_response(self, cmd):
         return (self._buffer[0] == 0x76 and self._buffer[1] == _SERIAL and

examples/snapshot.py

@@ -18,9 +18,7 @@
 
 
 # Configuration:
-SD_CS_PIN = board.SD_CS  # CS for SD card (SD_CS is for Feather Adalogger)
-RX_PIN = board.RX     # RX pin of board, connected to VC0706 TX
-TX_PIN = board.TX     # TX pin of board, connected to VC0706 RX
+SD_CS_PIN = board.D10  # CS for SD card (SD_CS is for Feather Adalogger)
 IMAGE_FILE = '/sd/image.jpg'  # Full path to file name to save captured image.
                               # Will overwrite!
 
@@ -33,13 +31,18 @@
 vfs = storage.VfsFat(sdcard)
 storage.mount(vfs, '/sd')
 
-# Setup VC0706.
-vc0706 = adafruit_vc0706.VC0706(RX_PIN, TX_PIN)
+# Create a serial connection for the VC0706 connection, speed is auto-detected.
+uart = busio.UART(board.TX, board.RX, timeout=250)
+# Setup VC0706 camera
+vc0706 = adafruit_vc0706.VC0706(uart)
 
 # Print the version string from the camera.
 print('VC0706 version:')
 print(vc0706.version)
 
+# Set the baud rate to 115200 for fastest transfer (its the max speed)
+vc0706.baudrate = 115200
+
 # Set the image size.
 vc0706.image_size = adafruit_vc0706.IMAGE_SIZE_640x480 # Or set IMAGE_SIZE_320x240 or
                                                        # IMAGE_SIZE_160x120

examples/snapshot_computer.py

@@ -0,0 +1,77 @@
+# VC0706 image capture to local storage.
+# You must wire up the VC0706 to a USB or hardware serial port.
+# Primarily for use with Linux/Raspberry Pi but also can work with Mac/Windows
+
+import time
+import serial
+import adafruit_vc0706
+
+# Configuration:
+IMAGE_FILE = 'image.jpg'  # Full path to file name to save captured image.
+                          # Will overwrite!
+
+# Create a serial connection for the VC0706 connection, speed is auto-detected.
+# Update the serial port name to match the serial connection for the camera!
+uart = serial.Serial("/dev/ttyUSB0", timeout=0.25)
+
+# Setup VC0706 camera
+vc0706 = adafruit_vc0706.VC0706(uart)
+
+# Print the version string from the camera.
+print('VC0706 version:')
+print(vc0706.version)
+
+# Set the baud rate to 115200 for fastest transfer (its the max speed)
+vc0706.baudrate = 115200
+
+# Set the image size.
+vc0706.image_size = adafruit_vc0706.IMAGE_SIZE_640x480 # Or set IMAGE_SIZE_320x240 or
+                                                       # IMAGE_SIZE_160x120
+# Note you can also read the property and compare against those values to
+# see the current size:
+size = vc0706.image_size
+if size == adafruit_vc0706.IMAGE_SIZE_640x480:
+    print('Using 640x480 size image.')
+elif size == adafruit_vc0706.IMAGE_SIZE_320x240:
+    print('Using 320x240 size image.')
+elif size == adafruit_vc0706.IMAGE_SIZE_160x120:
+    print('Using 160x120 size image.')
+
+# Take a picture.
+print('Taking a picture in 3 seconds...')
+time.sleep(3)
+print('SNAP!')
+if not vc0706.take_picture():
+    raise RuntimeError('Failed to take picture!')
+
+# Print size of picture in bytes.
+frame_length = vc0706.frame_length
+print('Picture size (bytes): {}'.format(frame_length))
+
+# Open a file for writing (overwriting it if necessary).
+# This will write 50 bytes at a time using a small buffer.
+# You MUST keep the buffer size under 100!
+print('Writing image: {}'.format(IMAGE_FILE), end='', flush=True)
+stamp = time.monotonic()
+with open(IMAGE_FILE, 'wb') as outfile:
+    wcount = 0
+    while frame_length > 0:
+        t = time.monotonic()
+        # Compute how much data is left to read as the lesser of remaining bytes
+        # or the copy buffer size (32 bytes at a time).  Buffer size MUST be
+        # a multiple of 4 and under 100.  Stick with 32!
+        to_read = min(frame_length, 32)
+        copy_buffer = bytearray(to_read)
+        # Read picture data into the copy buffer.
+        if vc0706.read_picture_into(copy_buffer) == 0:
+            raise RuntimeError('Failed to read picture frame data!')
+        # Write the data to SD card file and decrement remaining bytes.
+        outfile.write(copy_buffer)
+        frame_length -= 32
+        # Print a dot every 2k bytes to show progress.
+        wcount += 1
+        if wcount >= 64:
+            print('.', end='', flush=True)
+            wcount = 0
+print()
+print('Finished in %0.1f seconds!' % (time.monotonic() - stamp))

examples/snapshot_internal.py

@@ -10,16 +10,16 @@
 import adafruit_vc0706
 
 # Configuration:
-RX_PIN = board.RX     # RX pin of board, connected to VC0706 TX
-TX_PIN = board.TX     # TX pin of board, connected to VC0706 RX
 IMAGE_FILE = '/image.jpg' # Full path to file name to save captured image.
                           # Will overwrite!
 
 # Setup SPI bus (hardware SPI).
 spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
 
-# Setup VC0706.
-vc0706 = adafruit_vc0706.VC0706(RX_PIN, TX_PIN)
+# Create a serial connection for the VC0706 connection, speed is auto-detected.
+uart = busio.UART(board.TX, board.RX, timeout=250)
+# Setup VC0706 camera
+vc0706 = adafruit_vc0706.VC0706(uart)
 
 # Print the version string from the camera.
 print('VC0706 version:')