--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/prologix.py Mon Dec 17 18:59:45 2007 +0100
@@ -0,0 +1,117 @@
+"""
+Prologix
+========
+
+Module defining a communication object to talk to Prologix USB-GPIB controler.
+
+"""
+import serial
+import time
+
+import gpib
+from gpib import ConnectionError
+
+GPIB_CONTROLLER = 1
+GPIB_DEVICE = 0
+
+class GPIB(object):
+ _retries = 15
+ def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1,
+ address=0, mode=1):
+ """
+ Create a new GPIB controller for the Prologix USB-GPIB device
+ located on serial device 'device'.
+ """
+ self._cnx = serial.Serial(port=device, baudrate=baudrate, timeout=timeout)
+ self._timeout = timeout
+
+ self.set_mode(mode)
+ self.set_address(address)
+
+ def set_address(self, address):
+ """
+ Set the address of the GPIB device:
+
+ - if the device is the Controller In Charge, this is the
+ address of the device commands are sent to,
+
+ - if the device is in GPIB_DEVICE mode, this is its address.
+ """
+ self._set_cmd('addr', address)
+ self._adress = address
+
+ def set_mode(self, mode):
+ """
+ Set GPIB device mode to 'mode':
+
+ - GPIB_CONTROLLER: set the device as the Controller In Charge
+ on the GPIB bus
+
+ - GPIB_DEVICE: set the device as a standard GPIB device on the
+ bus.
+ """
+ self._set_cmd('mode', mode)
+ self._mode = mode
+
+ def set_controller(self):
+ """
+ Set GPIB device the Controller In Charge on the GPIB bus.
+ """
+ self.set_mode(1)
+
+ def set_device(self):
+ """
+ Set the GPIB device as a simple device on the GPIB bus.
+ """
+ self.set_mode(0)
+
+ def send_command(self, cmd):
+ """
+ Send the specified GPIB command on the bus (must be the CIC),
+ and read the answer.
+ """
+ assert self._mode == 1
+ self._cnx.write(cmd+'\r')
+ time.sleep(self._timeout) # required?
+ ret = self._cnx.readlines()
+ return ''.join(ret)
+
+ def check_srq(self):
+ """
+ Check the SRQ line
+ """
+ assert self._mode == 1, "must be the Controller In Charge"
+ self._cnx.write('++srq\r')
+ ret = self._cnx.readline().strip()
+ if ret:
+ return bool(int(ret))
+ return None
+
+ def poll(self):
+ """
+ Poll every address, and return a dictionnary
+ {add: status, ...}
+ """
+ assert self._mode == 1, "must be the Controller In Charge"
+ dico = {}
+ for add in range(31):
+ self._cnx.write('++spoll %d\r'%i)
+ ret = self._cnx.readline().strip()
+ if ret:
+ dico[i] = int(ret)
+ return dico
+
+ def _read(self):
+ for i in range(self._retries):
+ rdata = self._cnx.readline()
+ if rdata.strip() != "":
+ break
+ time.sleep(self._timeout)
+ return rdata
+
+ def _set_cmd(self, cmd, value):
+ self._cnx.write('++%s %d\r'%(cmd, value))
+ self._cnx.write('++%s\r'%(cmd))
+ rval = self._read().strip()
+ if not rval.isdigit() or int(rval) != value:
+ raise ConnectionError("Can't set GPIB %s to %s [ret=%s]"%(cmd, value, repr(rval)))