带有SD卡和USB MSD接口的CAN数据记录器

如果我记得正确，这是正常的行为：Microchip MLA用于在USB级别执行“分离”和“附加”，从而Windows会注意到这些变化。



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    If I recall correctly, this is the normal behaviour: Microchip MLA used to perform a "Detach" and a "Attach" at the USB level, so that Windows would notice the changes...

我怎样才能做一个和谐的附加/分离？谢谢你的快速回答



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    How can I do an attach/detach in Harmony? Thanks for the fast answer

唉，我没有线索…搜索一些类似上面名字的函数……“USBDetach”



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    Ahem, I've got no clue...
Search for some function with similar names as above... "USBAttach", "USBDetach"

我将搜索这些功能



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    Welp I'll search for those functions

在Windows中枚举了USB MSD设备之后，它执行一系列读取以查找MSD设备上存在的文件系统的类型。它缓存此信息，一般不重新读取与文件系统相关的元数据。它只涉及写入操作时文件系统元数据的更新（写入）。因此，使用在PIC32上运行的和声FS对媒体进行的任何更改对于Windows主机都是不可见的，直到该元数据再次被读取为止。这可以通过强制USB重新枚举来实现。Ortho提供API执行USB附加/分离，例如UBS.DeVice附件（）和UBSDEVICEXORDECH（），可以用来实现这一点。有一个演示演示了这种双重用途，是标准发布的和谐释放的一部分。它位于：ApvsUSB设备MSDYFSSYSPIFlash。这个演示使用一个开关来控制媒体之间的和谐的FS和Windows（通过USB MSD）的所有权。



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    After the USB MSD device has been enumerated by the windows, it performs a series of reads to find the type of file system present on the MSD device. It caches this information and does not read the file system related metadata again generally. It only updates(writes) the filesystem metadata when a write operation is involved. So any changes done to the media using the Harmony FS running on PIC32 will not be visible to the windows host until this metadata is read again. This can be achieved by forcing a USB re-enumeration.
 
Harmony provides APIs to perform USB attach/detach such as USB_DEVICE_Attach () and USB_DEVICE_Detach () which can be used to achieve this. There is an application demo that showcases this dual usage and is part of the standard demos of the Harmony release. It is located at: appsu***devicemsd_fs_spiflash. This demo uses a switch to control the ownership of the media between the Harmony FS and the windows(through USB MSD).

是的，我要使用这些函数，我只需要找出一个避免恼人窗口弹出的方法：P谢谢你的答案



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    Yes I'm gonna use those functions, I only need to figure out a way of avoiding the annoying windows popup :P Thanks for you answers

如果我不知怎么能把SD分离到Windows会发生什么？



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    What happens if I somehow could "detach the SD" to windows?

你到底是什么意思？正如上面所说的，Windows可以“弹出”并刷新设备的目录：



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    What do you mean exactly?
As you said above, Windows may "popup" and refresh the device's directory :)

是的，但是这会“杀死”我的HID设备句柄，并使PC软件变得混乱：P，所以如果强迫假“SD卡分离”会起作用。



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    Yeah but that "kills" my HID device handle and makes the PC software a mess :P so maybe if forcing a fake "sd card detach" would do the trick

我没有解释我自己，我有一个HID和MSD的USB设备。最初的想法是这个记录器将数据写入SD卡，而PC只是通过改变读取文件。我使用HID函数来发送命令和数据。



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    I didn't explain myself,
 
I have a USB device with HID & MSD. The original idea was that this logger writes data to the SD card and the PC just reads the file with the changes. I use the HID function to send commands and data.
 

是的，然后我得到它，我也创造了这样的复合物，但从来没有执行分离等。所以我不确定你能做什么。理论上，你可以在HID信道上发送一个命令，导致“不知何故”MSD侧强制刷新，但是…我不确定。或者你可以通过HID检索目录不是很好但是…



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    Yeah, then I got it
I also created such composite things, but never had to perform Detach etc... so am not sure what you could do.
 
In theory you could send a command on the HID channel causing "somehow" the MSD side to force a refresh but... am not sure. Or you could retrieve a DIRectory via HID not so nice but ...

它确实有意义，因为MSD永远不会自己写数据。我发现了一种卸载驱动器然后再安装的方法。更新所有的书面更改



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    It does make sense, because a MSD will never write data on it's own. I discovered a way of unmounting the drive then mounting it again. That does update all the written changes