add dsrdtr setting, allows independent seeting of rts/cts and dsr/dtr flow control on platforms where this is possible

3 files changed, 34 insertions, 7 deletions

diff --git a/pyserial/CHANGES.txt b/pyserial/CHANGES.txt
index 7f93e64..1eacd11 100644
--- a/pyserial/CHANGES.txt
+++ b/pyserial/CHANGES.txt
@@ -156,3 +156,8 @@ Version 2.2     XXXX
     Bugfixes (win32):
         - keep RTS/CTS state on port setting changes [Patch 983106]
 
+    New Features:
+        - dsrdtr setting to enable/disable DSR/DTR flow control independently
+          from the rtscts setting. (Currenly Win32 only, ignored on other
+          platforms)
+
diff --git a/pyserial/serial/serialutil.py b/pyserial/serial/serialutil.py
index 053aca7..e608264 100644
--- a/pyserial/serial/serialutil.py
+++ b/pyserial/serial/serialutil.py
@@ -122,6 +122,7 @@ class SerialBase(FileLike):
                  xonxoff=0,             #enable software flow control
                  rtscts=0,              #enable RTS/CTS flow control
                  writeTimeout=None,     #set a timeout for writes
+                 dsrdtr=None,           #None: use rtscts setting, dsrdtr override if true or false
                  ):
         """Initialize comm port object. If a port is given, then the port will be
            opened immediately. Otherwise a Serial port object in closed state
@@ -137,6 +138,7 @@ class SerialBase(FileLike):
         self._writeTimeout  = None           #correct value is assigned below trough properties
         self._xonxoff  = None           #correct value is assigned below trough properties
         self._rtscts   = None           #correct value is assigned below trough properties
+        self._dsrdtr   = None           #correct value is assigned below trough properties
         
         #assign values using get/set methods using the properties feature
         self.port     = port
@@ -148,6 +150,7 @@ class SerialBase(FileLike):
         self.writeTimeout = writeTimeout
         self.xonxoff  = xonxoff
         self.rtscts   = rtscts
+        self.dsrdtr   = dsrdtr
         
         if port is not None:
             self.open()
@@ -308,21 +311,37 @@ class SerialBase(FileLike):
     xonxoff = property(getXonXoff, setXonXoff, doc="Xon/Xoff setting")
 
     def setRtsCts(self, rtscts):
-        """Change RtsCts setting."""
+        """Change RtsCts flow control setting."""
         self._rtscts = rtscts
         if self._isOpen: self._reconfigurePort()
     
     def getRtsCts(self):
-        """Get the current RtsCts setting."""
+        """Get the current RtsCts flow control setting."""
         return self._rtscts
     
-    rtscts = property(getRtsCts, setRtsCts, doc="RTS/CTS setting")
+    rtscts = property(getRtsCts, setRtsCts, doc="RTS/CTS flow control setting")
 
+    def setDsrDtr(self, dsrdtr=None):
+        """Change DsrDtr flow control setting."""
+        if dsrdtr is None:
+            #if not set, keep backwards compatibility and follow rtscts setting
+            self._dsrdtr = self._rtscts
+        else:
+            #if defined independently, follow its value
+            self._dsrdtr = dsrdtr
+        if self._isOpen: self._reconfigurePort()
+    
+    def getDsrDtr(self):
+        """Get the current DsrDtr flow control setting."""
+        return self._dsrdtr
+    
+    dsrdtr = property(getDsrDtr, setDsrDtr, "DSR/DTR flow control setting")
+    
     #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
 
     def __repr__(self):
         """String representation of the current port settings and its state."""
-        return "%s<id=0x%x, open=%s>(port=%r, baudrate=%r, bytesize=%r, parity=%r, stopbits=%r, timeout=%r, xonxoff=%r, rtscts=%r)" % (
+        return "%s<id=0x%x, open=%s>(port=%r, baudrate=%r, bytesize=%r, parity=%r, stopbits=%r, timeout=%r, xonxoff=%r, rtscts=%r, dsrdtr=%r)" % (
             self.__class__.__name__,
             id(self),
             self._isOpen,
@@ -334,6 +353,7 @@ class SerialBase(FileLike):
             self.timeout,
             self.xonxoff,
             self.rtscts,
+            self.dsrdtr,
         )
 
 if __name__ == '__main__':
diff --git a/pyserial/serial/serialwin32.py b/pyserial/serial/serialwin32.py
index af94bd8..cda6205 100644
--- a/pyserial/serial/serialwin32.py
+++ b/pyserial/serial/serialwin32.py
@@ -11,7 +11,7 @@ import win32event # We use events and the WaitFor[Single|Multiple]Objects functi
 import win32con   # constants.
 from serialutil import *
 
-VERSION = "$Revision: 1.30 $".split()[1]     #extract CVS version
+VERSION = "$Revision: 1.31 $".split()[1]     #extract CVS version
 
 #from winbase.h. these should realy be in win32con
 MS_CTS_ON  = 16
@@ -142,12 +142,14 @@ class Serial(SerialBase):
         # Char. w/ Parity-Err are replaced with 0xff (if fErrorChar is set to TRUE)
         if self._rtscts:
             comDCB.fRtsControl  = win32file.RTS_CONTROL_HANDSHAKE
-            comDCB.fDtrControl  = win32file.DTR_CONTROL_HANDSHAKE
         else:
             comDCB.fRtsControl  = self._rtsState
+        if self._dsrdtr:
+            comDCB.fDtrControl  = win32file.DTR_CONTROL_HANDSHAKE
+        else:
             comDCB.fDtrControl  = self._dtrState
         comDCB.fOutxCtsFlow     = self._rtscts
-        comDCB.fOutxDsrFlow     = self._rtscts
+        comDCB.fOutxDsrFlow     = self._dsrdtr
         comDCB.fOutX            = self._xonxoff
         comDCB.fInX             = self._xonxoff
         comDCB.fNull            = 0