#!/usr/bin/env python # parallel port access using the ppdev driver import struct import fcntl import os #---- # Generated by h2py 0.1.1 from , # then cleaned up a bit by Michael P. Ashton and then a gain by chris ;-) def sizeof(type): return struct.calcsize(type) def _IOC(dir, type, nr, size): return (dir << _IOC_DIRSHIFT ) | (type << _IOC_TYPESHIFT ) |\ (nr << _IOC_NRSHIFT ) | (size << _IOC_SIZESHIFT) def _IO(type, nr): return _IOC(_IOC_NONE, type, nr, 0) def _IOR(type,nr,size): return _IOC(_IOC_READ, type, nr, sizeof(size)) def _IOW(type,nr,size): return _IOC(_IOC_WRITE, type, nr, sizeof(size)) _IOC_SIZEBITS = 14 _IOC_SIZEMASK = (1 << _IOC_SIZEBITS ) - 1 _IOC_NRSHIFT = 0 _IOC_NRBITS = 8 _IOC_TYPESHIFT = _IOC_NRSHIFT + _IOC_NRBITS _IOC_TYPEBITS = 8 _IOC_SIZESHIFT = _IOC_TYPESHIFT + _IOC_TYPEBITS IOCSIZE_MASK = _IOC_SIZEMASK << _IOC_SIZESHIFT IOCSIZE_SHIFT = _IOC_SIZESHIFT _IOC_WRITE = 1 _IOC_DIRSHIFT = _IOC_SIZESHIFT + _IOC_SIZEBITS IOC_IN = _IOC_WRITE << _IOC_DIRSHIFT _IOC_READ = 2 IOC_INOUT = (_IOC_WRITE | _IOC_READ) << _IOC_DIRSHIFT IOC_OUT = _IOC_READ << _IOC_DIRSHIFT _IOC_NONE = 0 PP_IOCTL = ord('p') PPCLAIM = _IO(PP_IOCTL, 0x8b) PPCLRIRQ = _IOR(PP_IOCTL, 0x93, 'i') PPDATADIR = _IOW(PP_IOCTL, 0x90, 'i') PPEXCL = _IO(PP_IOCTL, 0x8f) PPFCONTROL = _IOW(PP_IOCTL, 0x8e, 'BB') PPGETFLAGS = _IOR(PP_IOCTL, 0x9a, 'i') PPGETMODE = _IOR(PP_IOCTL, 0x98, 'i') PPGETMODES = _IOR(PP_IOCTL, 0x97, 'I') PPGETPHASE = _IOR(PP_IOCTL, 0x99, 'i') PPGETTIME = _IOR(PP_IOCTL, 0x95, 'll') PPNEGOT = _IOW(PP_IOCTL, 0x91, 'i') PPRCONTROL = _IOR(PP_IOCTL, 0x83, 'B') PPRDATA = _IOR(PP_IOCTL, 0x85, 'B') #'OBSOLETE__IOR' undefined in 'PPRECONTROL' PPRELEASE = _IO(PP_IOCTL, 0x8c) #'OBSOLETE__IOR' undefined in 'PPRFIFO' PPRSTATUS = _IOR(PP_IOCTL, 0x81, 'B') PPSETFLAGS = _IOW(PP_IOCTL, 0x9b, 'i') PPSETMODE = _IOW(PP_IOCTL, 0x80, 'i') PPSETPHASE = _IOW(PP_IOCTL, 0x94, 'i') PPSETTIME = _IOW(PP_IOCTL, 0x96, 'll') PPWCONTROL = _IOW(PP_IOCTL, 0x84, 'B') PPWCTLONIRQ = _IOW(PP_IOCTL, 0x92, 'B') PPWDATA = _IOW(PP_IOCTL, 0x86, 'B') #'OBSOLETE__IOW' undefined in 'PPWECONTROL' #'OBSOLETE__IOW' undefined in 'PPWFIFO' #'OBSOLETE__IOW' undefined in 'PPWSTATUS' PPYIELD = _IO(PP_IOCTL, 0x8d) PP_FASTREAD = 1 << 3 PP_FASTWRITE = 1 << 2 PP_W91284PIC = 1 << 4 PP_FLAGMASK = PP_FASTWRITE | PP_FASTREAD | PP_W91284PIC PP_MAJOR = 99 _ASMI386_IOCTL_H= None _IOC_DIRBITS = 2 _IOC_DIRMASK = (1 << _IOC_DIRBITS) - 1 _IOC_NRMASK = (1 << _IOC_NRBITS) - 1 _IOC_TYPEMASK = (1 << _IOC_TYPEBITS ) - 1 def _IOC_DIR(nr): return (nr >> _IOC_DIRSHIFT) & _IOC_DIRMASK def _IOC_NR(nr): return (nr >> _IOC_NRSHIFT) & _IOC_NRMASK def _IOC_SIZE(nr): return (nr >> _IOC_SIZESHIFT) & _IOC_SIZEMASK def _IOC_TYPE(nr): return (nr >> _IOC_TYPESHIFT) & _IOC_TYPEMASK def _IOWR(type, nr, size): return _IOC(_IOC_READ | _IOC_WRITE, type, nr , sizeof(size)) __ELF__ = 1 __i386 = 1 __i386__ = 1 __linux = 1 __linux__ = 1 __unix = 1 __unix__ = 1 i386 = 1 linux = 1 unix = 1 #-------- Constants from PARPORT_CONTROL_STROBE = 0x1 PARPORT_CONTROL_AUTOFD = 0x2 PARPORT_CONTROL_INIT = 0x4 PARPORT_CONTROL_SELECT = 0x8 PARPORT_STATUS_ERROR = 8 PARPORT_STATUS_SELECT = 0x10 PARPORT_STATUS_PAPEROUT = 0x20 PARPORT_STATUS_ACK = 0x40 PARPORT_STATUS_BUSY = 0x80 IEEE1284_MODE_NIBBLE = 0 IEEE1284_MODE_BYTE = 1 IEEE1284_MODE_COMPAT = 1<<8 IEEE1284_MODE_BECP = 1<<9 IEEE1284_MODE_ECP = 1<<4 IEEE1284_MODE_ECPRLE = IEEE1284_MODE_ECP | (1<<5) IEEE1284_MODE_ECPSWE = 1<<10 IEEE1284_MODE_EPP = 1<<6 IEEE1284_MODE_EPPSL = 1<<11 IEEE1284_MODE_EPPSWE = 1<<12 IEEE1284_DEVICEID = 1<<2 IEEE1284_EXT_LINK = 1<<14 IEEE1284_ADDR = 1<<13 IEEE1284_DATA = 0 PARPORT_EPP_FAST = 1 PARPORT_W91284PIC = 2 #---- class Parallel: """Class for controlling the pins on a parallel port This class provides bit-level access to the pins on a PC parallel port. It is primarily designed for programs which must control special circuitry - most often non-IEEE-1284-compliant devices other than printers - using 'bit-banging' techniques. The current implementation makes ioctl() calls to the Linux ppdev driver, using the Python fcntl library. It might be rewritten in C for extra speed. This particular implementation is written for Linux; all of the upper-level calls can be ported to Windows as well. On Linux, the ppdev device driver, from the Linux 2.4 parallel port subsystem, is used to control the parallel port hardware. This driver must be made available from a kernel compile. The option is called "Support user-space parallel-port drivers". When using the module, be sure to unload the lp module first: usually the lp module claims exclusive access to the parallel port, and if it is loaded, this class will fail to open the parallel port file, and throw an exception. The primary source of information about the Linux 2.4 parallel port subsystem is Tim Waugh's documentation, the source for which is available in the kernel tree. This document (called, appropriately enough, "The Linux 2.4 Parallel Port Subsystem"), thoroughly describes the parallel port drivers and how to use them. This class provides a method for each of the ioctls supported by the ppdev module. The ioctl methods are named, in uppercase, the same as the ioctls they invoke. The documentation for these methods was taken directly from the documentation for their corresponding ioctl, and modified only where necessary. Unless you have special reason to use the Linux ioctls, you should use instead the upper-level functions, which are named in lowerCase fashion and should be portable between Linux and Windows. This way, any code you write for this class will (or should) also work with the Windows version of this class. """ def __init__(self, port = 0): if type(port) == type(""): self.device = port else: self.device = "/dev/parport%d" % port self._fd = os.open(self.device, os.O_RDWR) self.PPEXCL() self.PPCLAIM() self.setDataDir(1) self.setData(0) def __del__(self): self.PPRELEASE() if self._fd is not None: os.close(self._fd) def timevalToFloat(self, timeval): t=struct.unpack('ll', timeval) return t[0] + (t[1]/1000000.0) def floatToTimeval(self, time): sec = int(time) usec = int(time*1000000.0) return struct.pack('ll', sec, usec) def PPCLAIM(self): """ Claims access to the port. As a user-land device driver writer, you will need to do this before you are able to actually change the state of the parallel port in any way. Note that some operations only affect the ppdev driver and not the port, such as PPSETMODE; they can be performed while access to the port is not claimed. """ fcntl.ioctl(self._fd, PPCLAIM) def PPEXCL(self): """ Instructs the kernel driver to forbid any sharing of the port with other drivers, i.e. it requests exclusivity. The PPEXCL command is only valid when the port is not already claimed for use, and it may mean that the next PPCLAIM ioctl will fail: some other driver may already have registered itself on that port. Most device drivers don't need exclusive access to the port. It's only provided in case it is really needed, for example for devices where access to the port is required for extensive periods of time (many seconds). Note that the PPEXCL ioctl doesn't actually claim the port there and then---action is deferred until the PPCLAIM ioctl is performed. """ fcntl.ioctl(self._fd, PPEXCL) def PPRELEASE(self): """ Releases the port. Releasing the port undoes the effect of claiming the port. It allows other device drivers to talk to their devices (assuming that there are any). """ fcntl.ioctl(self._fd, PPRELEASE) def PPYIELD(self): """ Yields the port to another driver. This ioctl is a kind of short-hand for releasing the port and immediately reclaiming it. It gives other drivers a chance to talk to their devices, but afterwards claims the port back. An example of using this would be in a user-land printer driver: once a few characters have been written we could give the port to another device driver for a while, but if we still have characters to send to the printer we would want the port back as soon as possible. It is important not to claim the parallel port for too long, as other device drivers will have no time to service their devices. If your device does not allow for parallel port sharing at all, it is better to claim the parallel port exclusively (see PPEXCL). """ fcntl.ioctl(self._fd, PPYIELD) def PPNEGOT(self, mode): """ Performs IEEE 1284 negotiation into a particular mode. Briefly, negotiation is the method by which the host and the peripheral decide on a protocol to use when transferring data. An IEEE 1284 compliant device will start out in compatibility mode, and then the host can negotiate to another mode (such as ECP). The 'mode' parameter should be one of the following constants from PPDEV: - IEEE1284_MODE_COMPAT - IEEE1284_MODE_NIBBLE - IEEE1284_MODE_BYTE - IEEE1284_MODE_EPP - IEEE1284_MODE_ECP The PPNEGOT ioctl actually does two things: it performs the on-the-wire negotiation, and it sets the behaviour of subsequent read/write calls so that they use that mode (but see PPSETMODE). """ fcntl.ioctl(self._fd, PPNEGOT, struct.pack('i', mode)) def PPSETMODE(self, mode): """ Sets which IEEE 1284 protocol to use for the read and write calls. The 'mode' parameter should be one of the following constants from PPDEV: - IEEE1284_MODE_COMPAT - IEEE1284_MODE_NIBBLE - IEEE1284_MODE_BYTE - IEEE1284_MODE_EPP - IEEE1284_MODE_ECP """ fcntl.ioctl(self._fd, PPSETMODE, struct.pack('i', mode)) def PPGETMODE(self): """ Retrieves the IEEE 1284 mode being used for read and write. The return value is one of the following constants from PPDEV: - IEEE1284_MODE_COMPAT - IEEE1284_MODE_NIBBLE - IEEE1284_MODE_BYTE - IEEE1284_MODE_EPP - IEEE1284_MODE_ECP """ ret = struct.pack('i', 0) ret = fcntl.ioctl(self._fd, PPGETMODE, ret) return struct.unpack('i', ret)[0] def PPGETTIME(self): """ Retrieves the time-out value. The read and write calls will time out if the peripheral doesn't respond quickly enough. The PPGETTIME ioctl retrieves the length of time that the peripheral is allowed to have before giving up. Returns the timeout value in seconds as a floating-point value. """ ret = struct.pack('ll', 0, 0) ret = fcntl.ioctl(self._fd, PPGETTIME, ret) return timevalToFloat(ret) def PPSETTIME(self, time): """ Sets the time-out (see PPGETTIME for more information). 'time' is the new time-out in seconds; floating-point values are acceptable. """ fcntl.ioctl(self._fd, PPSETTIME, floatToTimeval(time)) def PPGETMODES(self): """ Retrieves the capabilities of the hardware (i.e. the modes field of the parport structure). """ raise NotImplementedError def PPSETFLAGS(self): """ Sets flags on the ppdev device which can affect future I/O operations. Available flags are: - PP_FASTWRITE - PP_FASTREAD - PP_W91284PIC """ raise NotImplementedError def PPWCONTROL(self, lines): """ Sets the control lines. The 'lines' parameter is a bitwise OR of the following constants from PPDEV: - PARPORT_CONTROL_STROBE - PARPORT_CONTROL_AUTOFD - PARPORT_CONTROL_INIT - PARPORT_CONTROL_SELECT """ fcntl.ioctl(self._fd, PPWCONTROL, struct.pack('B', lines)) def PPRCONTROL(self): """ Returns the last value written to the control register, in the form of an integer, for which each bit corresponds to a control line (although some are unused). This doesn't actually touch the hardware; the last value written is remembered in software. This is because some parallel port hardware does not offer read access to the control register. The control lines bits are defined by the following constants from PPDEV: - PARPORT_CONTROL_STROBE - PARPORT_CONTROL_AUTOFD - PARPORT_CONTROL_SELECT - PARPORT_CONTROL_INIT """ ret = struct.pack('B',0) ret = fcntl.ioctl(self._fd, PPRCONTROL, ret) return struct.unpack('B', ret)[0] def PPFCONTROL(self, mask, val): """ Frobs the control lines. Since a common operation is to change one of the control signals while leaving the others alone, it would be quite inefficient for the user-land driver to have to use PPRCONTROL, make the change, and then use PPWCONTROL. Of course, each driver could remember what state the control lines are supposed to be in (they are never changed by anything else), but in order to provide PPRCONTROL, ppdev must remember the state of the control lines anyway. The PPFCONTROL ioctl is for "frobbing" control lines, and is like PPWCONTROL but acts on a restricted set of control lines. The ioctl parameter is a pointer to a struct ppdev_frob_struct: struct ppdev_frob_struct { unsigned char mask; unsigned char val; }; The mask and val fields are bitwise ORs of control line names (such as in PPWCONTROL). The operation performed by PPFCONTROL is: new_ctr = (old_ctr & ~mask) | val In other words, the signals named in mask are set to the values in val. """ fcntl.ioctl(self._fd, PPFCONTROL, struct.pack('BB', mask, val)) def PPRSTATUS(self): """ Returns an unsigned char containing bits set for each status line that is set (for instance, PARPORT_STATUS_BUSY). The ioctl parameter should be a pointer to an unsigned char. """ ret = struct.pack('B',0) ret = fcntl.ioctl(self._fd, PPRSTATUS, ret) return struct.unpack('B', ret)[0] def PPDATADIR(self, out): """ Controls the data line drivers. Normally the computer's parallel port will drive the data lines, but for byte-wide transfers from the peripheral to the host it is useful to turn off those drivers and let the peripheral drive the signals. (If the drivers on the computer's parallel port are left on when this happens, the port might be damaged.) This is only needed in conjunction with PPWDATA or PPRDATA. The 'out' parameter indicates the desired port direction. If 'out' is true or non-zero, the drivers are turned on (forward direction); otherwise, the drivers are turned off (reverse direction). """ if out: msg=struct.pack('i',0) else: msg=struct.pack('i',1) fcntl.ioctl(self._fd, PPDATADIR, msg) def PPWDATA(self, byte): """ Sets the data lines (if in forward mode). The ioctl parameter is a pointer to an unsigned char. """ fcntl.ioctl(self._fd, PPWDATA,struct.pack('B',byte)) def PPRDATA(self): """ Reads the data lines (if in reverse mode). The ioctl parameter is a pointer to an unsigned char. """ ret=struct.pack('B',0) ret=fcntl.ioctl(self._fd, PPRDATA,ret) return struct.unpack('B',ret)[0] def PPCLRIRQ(self): """ Returns the current interrupt count, and clears it. The ppdev driver keeps a count of interrupts as they are triggered. """ ret=struct.pack('i',0) ret=fcntl.ioctl(self._fd, PPCLRIRQ,ret) return struct.unpack('i',ret)[0] def PPWCTLONIRQ(self, lines): """ Set a trigger response. Afterwards when an interrupt is triggered, the interrupt handler will set the control lines as requested. The ioctl parameter is a pointer to an unsigned char, which is interpreted in the same way as for PPWCONTROL. The reason for this ioctl is simply speed. Without this ioctl, responding to an interrupt would start in the interrupt handler, switch context to the user-land driver via poll or select, and then switch context back to the kernel in order to handle PPWCONTROL. Doing the whole lot in the interrupt handler is a lot faster. """ fcntl.ioctl(self._fd, PPWCTLONIRQ,struct.pack('B',lines)) #data lines ## def data(self): ## """Returns the states of the data bus line drivers (pins 2-9)""" ## return self._data def setDataDir(self,out): """Activates or deactivates the data bus line drivers (pins 2-9)""" self._dataDir = out self.PPDATADIR(out) def dataDir(self): """Returns true if the data bus line drivers are on (pins 2-9)""" return self._dataDir #control lines ## def strobe(self): ## """Returns the state of the nStrobe output (pin 1)""" ## return (self.PPRCONTROL()&PARPORT_CONTROL_STROBE)==0 def setDataStrobe(self, level): """Sets the state of the nStrobe output (pin 1)""" if level: self.PPFCONTROL(PARPORT_CONTROL_STROBE, 0) else: self.PPFCONTROL(PARPORT_CONTROL_STROBE, PARPORT_CONTROL_STROBE) ## def autoFd(self): ## """Returns the state of the nAutoFd output (pin 14)""" ## return (self.PPRCONTROL()&PARPORT_CONTROL_AUTOFD)==0 def setAutoFeed(self, level): """Sets the state of the nAutoFd output (pin 14)""" if level: self.PPFCONTROL(PARPORT_CONTROL_AUTOFD, 0) else: self.PPFCONTROL(PARPORT_CONTROL_AUTOFD, PARPORT_CONTROL_AUTOFD) ## def init(self): ## """Returns the state of the nInit output (pin 16)""" ## return (self.PPRCONTROL()&PARPORT_CONTROL_INIT)!=0 def setInitOut(self, level): """Sets the state of the nInit output (pin 16)""" if level: self.PPFCONTROL(PARPORT_CONTROL_INIT, PARPORT_CONTROL_INIT) else: self.PPFCONTROL(PARPORT_CONTROL_INIT, 0) ## def selectIn(self): ## """Returns the state of the nSelectIn output (pin 17)""" ## return (self.PPRCONTROL()&PARPORT_CONTROL_SELECT)==0 def setSelect(self,level): """Sets the state of the nSelectIn output (pin 17)""" if level: self.PPFCONTROL(PARPORT_CONTROL_SELECT, 0) else: self.PPFCONTROL(PARPORT_CONTROL_SELECT, PARPORT_CONTROL_SELECT) def setData(self,d): """Sets the states of the data bus line drivers (pins 2-9)""" self._data=d return self.PPWDATA(d) #status lines def getInError(self): """Returns the level on the nFault pin (15)""" return (self.PPRSTATUS() & PARPORT_STATUS_ERROR) != 0 def gettInSelected(self): """Returns the level on the Select pin (13)""" return (self.PPRSTATUS() & PARPORT_STATUS_SELECT) != 0 def getInPaperOut(self): """Returns the level on the paperOut pin (12)""" return (self.PPRSTATUS() & PARPORT_STATUS_PAPEROUT) != 0 def getInAcknowledge(self): """Returns the level on the nAck pin (10)""" return (self.PPRSTATUS() & PARPORT_STATUS_ACK) != 0 def getInBusy(self): """Returns the level on the Busy pin (11)""" return (self.PPRSTATUS() & PARPORT_STATUS_BUSY) == 0