| ??? 04/05/07 11:46 Read: times |
#136672 - Multiple USB Virtual COM Ports |
This is a "spin-off" from my thread SiLabs 8051+USB - deviates only?
Tsuneo Chinzei Raised the issue of multiple Virtual COM Ports for a single microcontroller: Tsuneo Chinzei said:
Either ST or Atmel example, they depend on Windows USB-serial device driver, usbser.sys. No one succeeds to make more than single virtual COM port on single device using usbser.sys.
Some managed to enumerate a composite device with two CDC (Communication Device Class, including virtual COM port) over usbser.sys, but it didn't work as virtual COM port(s). So, I said that the device driver development on the PC is required to realize more than single virtual COM port. http://www.8052.com/forum/read.phtml?id=136394 USB MCU can provide so-called direct ports for multiple UARTs on the chip. If you expect more than single virtual COM ports on the PC by the USB MCU, it is hopeless. It involves a device driver development on the PC, the most terrible work. In this case, I recommend you FTDI FT2232 (dual UART/FIFO USB-serial converter). From USB-IF forum "CDC device with multiple serial port" http://www.usb.org/phpbb/viewtopic.php?t=10626 "CDC composite device using IAD in Windows XP - SP2" http://www.usb.org/phpbb/viewtopic.php?t=7467 "Using USB Hub Class, to circumvent Windows Shortcomings" http://www.usb.org/phpbb/viewtopic.php?t=10724 This case is a good example that the development on device and PC are tightly related on USB application. Even if the device satisfies the requirement, but you cannot mange the PC side, the application isn't established. Tsuneo As it's diverged from the original subject of my Thread, I've started this one for further discussion of the above... |
| Topic | Author | Date |
| Multiple USB Virtual COM Ports | 01/01/70 00:00 | |
| CDC composite device | 01/01/70 00:00 | |
| So much for my idea | 01/01/70 00:00 | |
| Union function descriptor | 01/01/70 00:00 | |
| driver development | 01/01/70 00:00 | |
Composite device, again | 01/01/70 00:00 | |
| Virtual COM port vs Direct port | 01/01/70 00:00 | |
| what about real (non-virtual) | 01/01/70 00:00 | |
| And there are lots of serial-to-IP "adapters" | 01/01/70 00:00 |