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Forum: MCU User Forum
Topic: Silabs USB Bulk drvrs updated to handle EP0 data packet after cmd packet.

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Message to Edit: HTML is ON UBB Code is OFF Smilies Legend	Originally posted by naresh.rana on 01-05-2007 05:33 AM Hi Tsuneo Thanks for reply, Issue 1 : The device is not re-enumerated on mode switch over, the device stays in CDC, only the variable defined in the firmware changes ,which keeps track of device mode. when device is changed to mode 2 using vendor specific commands the data received on endpoints is treated as I/O port control command data. Earlier the data packet size was 64, but the Application on Host PC was freezing while communicating to device, when size was reduced to 63 every thing was working ok. I could not understand the behaviour of exe why it does not freezes when vcom window is opened at lest once. Is it something related to CDC deivce drivers implemented on windows ?. is the packet data size of 63/64 culprit for exe freezing,i suppose packet size should not be a issue till it is within max packet limits(as observed in USB traffic above the host wait for 668 bytes and device skips sending two packets and hence the exe freezes for data reception, but if VCom Hyperterminal window is opened once and device mode is changed this never happens!!). Issue 2: Tsuneo i would reexplain the issue 2 with help of setup diagram given below: <pre><font size =2> USB UART PC(Vcom) <---> C8051F340(CDC) <----> Device (supporting Xmodem file transfer) </font></pre> In "hyperterminal" menu bar,"Transfer -- send -- xmodem(from drop down menu)", if option is selected for xmodem type file tranfer,then there are handshake bytes passed between Hyperterminal and device( supporting xmodem data transfer), before the data actually starts transferring. Now since when the C8051F340 enumerates it self as Vcom port,if Hyperterminal window is opened for this port the same option of xmodem file transfer is available here too,but the file transfer returns error in this case whereas with normal com port Hyperterminal window this device does not gives error. Since Xmodem is file transfer protocol it too has ACk and NAK....so NAk in my previous post is actually NAK for Xmodem transfer and not for USB transfer. So the USB data transfer has no problem, its only that xmodem data transfer fails in virtual com hyperterminal of C8051F340. (i verified this behaviour with CP2103 Vcom hyperterminal ,it work fine here!!) Thanks, Naresh [This message has been edited by naresh.rana (edited January 05, 2007).] [This message has been edited by naresh.rana (edited January 05, 2007).]
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