diff -r 61809bb871bf -r 022e881b758e gpib.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gpib.py	Sat Jan 26 11:39:30 2008 +0100
@@ -0,0 +1,64 @@
+"""
+gpib: create serial connection to GPIB-USB device (ProLogix is the
+only supported device for now).
+"""
+import serial
+from serial.serialutil import SerialException
+import time
+
+class ConnectionError(Exception):
+    pass
+
+class Constants(object):
+    def __init__(self):
+        self.constants = {}
+        self.descriptions = {}
+        self.rev_constants = {}
+        for v, k, m in self._constants:
+            self.k = v
+            self.constants[v] = k
+            self.rev_constants[k] = v
+            self.descriptions[v] = m
+            
+    def __getitem__(self, k):
+        if isinstance(k, basestring):
+            return self.rev_constants[k]
+        else:
+            return self.constants[k]
+
+    def get_description(self, k):
+        if isinstance(k, basestring):
+            k = self.rev_constants[k]
+        return self.descriptions[k]
+    
+
+class MODE(Constants):    
+    _constants = [(1, "CONTROLLER", "Set device as Controller in Charge"),
+                  (0, "DEVICE", "Set device as simple listener"),
+                  ]
+# TODO
+# class STATUS_BYTE(Constants):
+#     # IEEE 488.2 Status Byte constants
+#     MAV = 0x10 # Message AVailable: bit 4 of the Status Byte
+#     ESB = 0x20 # Event Status Bit: bit 5 of the Status Byte
+#     MSS = 0x40 # Master Summary Status bit: bit 6 of the Status Byte (NOT
+#                # sent in response to a serial poll)
+#     RQS = 0x40 # Request Service: bit 6 of the Status Byte (when sent in
+#                # response to a serial poll)
+# class SESR(Constants):
+#     # SESR constants (Standard Event Status Register)
+#     PON = 0x80 # Power On: Power has been turned On since last register
+#                # read access
+#     URQ = 0x40 # User Request: the user has activated some device control
+#                # (whatever the Remote Local state is)
+#     CME = 0x20 # Command Error
+#     EXE = 0x10 # Execution Error
+#     DDE = 0x08 # Device Dependant Error
+#     QYE = 0x04 # QuerY Error (attempt to read data while Output Queue is
+#                # empty, or data in the OQ was lost)
+#     RQC = 0x02 # Request Control: tell the CiC that the device wants to
+#                # become the CiC
+#     OPC = 0x01 # Operation Complete: device has completed any pending
+#                # operation (ready to accept new commands). This bit is
+#                # generated in response to a OPC command.
+