• USBSER.SYS quirks explained
    Hi, I have been wrestling with Microsoft USBSER.SYS as my host driver for an MDK-PRO based Atmel project. We are using the USB CDC ACM middleware from Keil. (4.73 source) I have determined a...
  • Three USBCDC Interfaces support in usbser.sys ?
    I want to know that if USBCDC with three or more interfaces is supported by using usbser.sys. I can see three VirtualCOM in PC, but one of them shows "not used" in Windows Device Manager. So I can't...
  • USB CDC-ACM function class
    Hi, I use a modified version of Keil's USB CDC-ACM function class implementation. It works really well but I am having a problem in the way I am using it. I use the virtual COM-port to connect as...
  • CDC class trouble(IN EP)
    I am working on a virtual COM project using USB CDC class. I have such trouble. After enumeration,PC sends the bulk IN package and the device responds NAKs. When the device wants to transmit data...
  • Switch USB Class between MSC and CDC in runtime
    Does anyone know how to switch usb between msc and cdc dynamically when uisng Keil USB Stack? Not the composite mode.