Re: [Pyusb-users] Cleverboard part 3

[Wander L. <wan...@gm...>]

What are the constants PLUG_BULK_IN_EP and PLUG_BULK_OUT_EP?

2008/12/23 Phil Hannent <ph...@ha...>:
> 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
>
>
>
>
>
>
>
>
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