Add hardware handshake support for serial port based CAN interfaces

yegorich · yegorich · commit 1296a1dea91b · 2018-09-03T09:00:26.000+02:00
pySerial module provides 'rtscts' option to handle hardware handshake.
This setting will be extracted from __init__'s kwargs.

Example:

    bus = can.interface.Bus(bustype='slcan',
                            channel='/dev/ttyUSB0@3000000',
                            bitrate=1000000,
                            rtscts=True)
diff --git a/can/interfaces/serial/serial_can.py b/can/interfaces/serial/serial_can.py
@@ -34,7 +34,8 @@ class SerialBus(BusABC):
 
     """
 
-    def __init__(self, channel, baudrate=115200, timeout=0.1, *args, **kwargs):
+    def __init__(self, channel, baudrate=115200, timeout=0.1, rtscts=False,
+                 *args, **kwargs):
         """
         :param str channel:
             The serial device to open. For example "/dev/ttyS1" or
@@ -49,13 +50,16 @@ def __init__(self, channel, baudrate=115200, timeout=0.1, *args, **kwargs):
         :param float timeout:
             Timeout for the serial device in seconds (default 0.1).
 
+        :param bool rtscts:
+            turn hardware handshake (RTS/CTS) on and off
+
         """
         if not channel:
             raise ValueError("Must specify a serial port.")
 
         self.channel_info = "Serial interface: " + channel
         self.ser = serial.serial_for_url(
-            channel, baudrate=baudrate, timeout=timeout)
+            channel, baudrate=baudrate, timeout=timeout, rtscts=rtscts)
 
         super(SerialBus, self).__init__(channel=channel, *args, **kwargs)
 
@@ -108,8 +112,8 @@ def _recv_internal(self, timeout):
         Read a message from the serial device.
 
         :param timeout:
-            
-            .. warning:: 
+
+            .. warning::
                 This parameter will be ignored. The timeout value of the channel is used.
 
         :returns:
diff --git a/can/interfaces/slcan.py b/can/interfaces/slcan.py
@@ -12,7 +12,6 @@
 
 from __future__ import absolute_import
 
-import io
 import time
 import logging
 
@@ -42,9 +41,10 @@ class slcanBus(BusABC):
         83300:      'S9'
     }
 
-    _SLEEP_AFTER_SERIAL_OPEN = 2 # in seconds
+    _SLEEP_AFTER_SERIAL_OPEN = 2  # in seconds
 
-    def __init__(self, channel, ttyBaudrate=115200, timeout=1, bitrate=None, **kwargs):
+    def __init__(self, channel, ttyBaudrate=115200, timeout=1, bitrate=None,
+                 rtscts=False, **kwargs):
         """
         :param str channel:
             port of underlying serial or usb device (e.g. /dev/ttyUSB0, COM8, ...)
@@ -57,16 +57,18 @@ def __init__(self, channel, ttyBaudrate=115200, timeout=1, bitrate=None, **kwarg
             Poll interval in seconds when reading messages
         :param float timeout:
             timeout in seconds when reading message
+        :param bool rtscts:
+            turn hardware handshake (RTS/CTS) on and off
         """
 
-        if not channel: # if None or empty
+        if not channel:  # if None or empty
             raise TypeError("Must specify a serial port.")
 
         if '@' in channel:
             (channel, ttyBaudrate) = channel.split('@')
 
         self.serialPortOrig = serial.serial_for_url(
-            channel, baudrate=ttyBaudrate, timeout=timeout)
+            channel, baudrate=ttyBaudrate, timeout=timeout, rtscts=rtscts)
 
         time.sleep(self._SLEEP_AFTER_SERIAL_OPEN)
 
@@ -80,7 +82,7 @@ def __init__(self, channel, ttyBaudrate=115200, timeout=1, bitrate=None, **kwarg
         self.open()
 
         super(slcanBus, self).__init__(channel, ttyBaudrate=115200, timeout=1,
-                                       bitrate=None, **kwargs)
+                                       bitrate=None, rtscts=False, **kwargs)
 
     def write(self, string):
         if not string.endswith('\r'):
@@ -104,7 +106,7 @@ def _recv_internal(self, timeout):
         frame = []
 
         readStr = self.serialPortOrig.read_until(b'\r')
-        
+
         if not readStr:
             return None, False
         else:
