Hi Wanda,
I have a simple pyUSB code to send and read a message with the scan interface
of a multi-functional printer. But I encountered an error when reading back
from the scan with the following codes. Although the message I tried to send
was a meaningless one, I thought it should return something and not time-out.
Please help. I am using pyUSB 1.0 in WinVista.
Thanks,
Charlie
The error message is:
USBError: libusb0-dll:err [_usb_reap_async] timeout error
The codes are:
#!/usr/bin/env python
import usb.core
import usb.util
import sys, time
dev=usb.core.find()
print "Found a scaner; idVendor is 0x%x, idProduct is 0x%x\n" % (dev.idVendor,
dev.idProduct)
dev.set_configuration()
cfg = dev[0]
intf = cfg[(0,0)]
ep_write = intf[0].bEndpointAddress
ep_read = intf[1].bEndpointAddress
ep_read2 = intf[2].bEndpointAddress
print "ep_write = %xh" % int(ep_write)
print "ep_read = %xh" % int(ep_read)
print "ep_read2 = %xh" % int(ep_read2)
msg ='test'
s1 = dev.write(ep_write, msg, intf)
print "send msg: %s" % msg
print "return from write: %s" % s1
time.sleep(0.5)
raw_input('hit enter:')
retRead = dev.read(ep_read, 100, intf, 1000)
sret = ''.join([chr(x) for x in retRead])
print "return message: %s" % sret
The following are the outputs and the error log:
Found a scaner; idVendor is 0x3f0, idProduct is 0x9911
ep_write = 1h
ep_read = 82h
ep_read2 = 83h
send msg: test
return from write: 4
Traceback (most recent call last):
File "C:\Users\ChuCh\Desktop\scaniq\pyusb\scanTest\standalone.py", line 33,
in <module>
retRead = dev.read(ep_read, 100, intf, 1000)
File "C:\Python26\lib\site-packages\usb\core.py", line 624, in read
self.__get_timeout(timeout)
File "C:\Python26\lib\site-packages\usb\_debug.py", line 53, in do_trace
return f(*args, **named_args)
File "C:\Python26\lib\site-packages\usb\backend\libusb01.py", line 448, in
bulk_read
timeout)
File "C:\Python26\lib\site-packages\usb\backend\libusb01.py", line 531, in
__read
timeout
File "C:\Python26\lib\site-packages\usb\backend\libusb01.py", line 364, in
_check
raise USBError(errmsg)
USBError: libusb0-dll:err [_usb_reap_async] timeout error
------------------------------------------------------------------------------
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