What are the constants PLUG_BULK_IN_EP and PLUG_BULK_OUT_EP? 2008/12/23 Phil Hannent <p...@hannent.co.uk>: > Hello, > > Wander Lairson wrote: >> Well, I think you are doing things in the right way, may be the >> problem is a device protocol issue. Perhaps you are issuing the wrong >> command to get what you want... How do you get the storage capacity? >> How many bytes are expected to return? Please, post the code here >> (with comments). >> > > Thanks for the reply, I am going to try an paste functions to see if it > helps: > > This section says hello to the device in question and works just fine. > > sent_bytes = > self.handle.interruptWrite(PlugUSBDevice.PLUG_BULK_IN_EP, > PlugUSBDevice.MIMIO_HELLO, 1000) > print "Sent hello" > if sent_bytes: > read_bytes = > self.handle.interruptRead(PlugUSBDevice.PLUG_BULK_OUT_EP,8); > self.readDevice(read_bytes) > > readDevice starts: > def readDevice(self, response): > #response = > self.handle.interruptRead(PlugUSBDevice.PLUG_BULK_OUT_EP,8); > if response: > print "readDevice", response > if response == PlugUSBDevice.MAX_PACKET_SIZE: > return > #print response > #firstByte = response[0] > #print firstByte > #print [hex(d) for d in response] > if response[0] == 0x21: > print "Device responded to hello" > self.devicestate = response[1] > > And I get the device telling me it responded. I can now issue several > other commands which query the storage information in a similar way and > get the information I expect. My main issue is that I cannot issue a > data transmit command and get pen xy coordinates, I just get: > usb.USBError: No error > > I start it by issuing a command like the others: > def startDataXmit(self, timeout = 100): > sent_bytes = > self.handle.interruptWrite(PlugUSBDevice.PLUG_BULK_IN_EP, > PlugUSBDevice.MIMIO_STARTDATATRANS, 1000) > if sent_bytes: > read_bytes = > self.handle.interruptRead(PlugUSBDevice.PLUG_BULK_OUT_EP,sent_bytes); > self.readDevice(read_bytes) > print "startDataXmit" > > Then in a loop I call: > def getDataPacket(self, bytesToGet) : > """ > Assume bytesToGet is two bytes wide. > """ > print "getDataPacket" > read_bytes = > self.handle.interruptRead(PlugUSBDevice.PLUG_BULK_OUT_EP,bytesToGet); > #read_bytes = > self.handle.bulkRead(PlugUSBDevice.PLUG_BULK_OUT_EP,bytesToGet,1000) > self.readDevice(read_bytes) > > Where I get the "No error" error on the interruptRead line. The > documentation for the protocol does not talk about low level USB details > only that the if the data becomes out of sync I must issue a stop > command and re-sync the communication channel (of which I am not sure > what that is). > > Any hints on the "No error" problem? > > Regards > Phil Hannent > > > > > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Pyusb-users mailing list > Pyusb-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/pyusb-users > >
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