Hi. I'm a bit of a novice with ctypes and this is my first post here so please forgive any detected newbiness. After trying and searching I hereby give up and appeal to the pros out there who may be more intimately familiar with DeviceIoControl usage. I'm trying use Python to access a USB device based on Cypress FX2 (EZ-USB) type part. The first operation I'm attempting is to access a command that is supposed to return the microcontroller's PORTA value. Here's a minimal amount of code: retCode = k32.DeviceIoControl( dev.deviceHandle, IOCTL_EZUSB_VENDOR_OR_CLASS_REQUEST, byref(vrControl), sizeof(VENDOR_OR_CLASS_REQUEST_CONTROL), pBuffer, c_ushort(255), # READ_LENGTH, byref(retBytes), None) Where the vrControl is a struct like this: vrControl = VENDOR_OR_CLASS_REQUEST_CONTROL() vrControl.direction = VENDOR_REQUEST_DIRECTION_DEVICE2HOST vrControl.requestType = VENDOR_REQUEST_REQUESTTYPE_VENDOR vrControl.recipient = VENDOR_REQUEST_RECIPIENT_ENDPOINT vrControl.reqTypeResdBits = 0 vrControl.request = VR_PORTS vrControl.value = VR_PORTS_READ << 8 | value vrControl.index = port
kernal32.DeviceIoControl returns a 0, and kernal32.GetLastError() is returning a 995, which is, "ERROR_OPERATION_ABORTED. The I/O operation has been aborted because of either a thread exit or an application request" according to: http://msdn.microsoft.com/en-us/library/ms681381(VS.85).aspx The reason for the abort does not make sense to me. Anyone know what would most commonly cause this? What should be my next step? Thanks in advance, Mark
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