I installed MTP_T4 on the Teensy 3.5 and made the modifications to the usb_desc.h.
I am using arduino IDE with Teensyduino version 1.54-beta 9

1. The device shows up in the device manager as MTP USB Device not Teensy MTP device.
2. It is not showing up in Windows explorer.
3. After making the changes to USB_DESC should there be a Serial device in device manager for the Teensy 3.5?

I am going to also post this to the pjrc forum when it is up but it is currently down, though you may like a note here.

Teensy 4.1 is used as data logger ,however after doing the changes in files as mentioned in MTP_t4 there is no Teensy as storage device
although the data is updated in sdcard (32 GB). the same changes done in other computer shows it as storage but when i upload program from my computer it fails as storage .system specifications are Teensy 4.1,windows 10,Teensyduino, Version 1.5,arduino-1.8.19

I can't seem to get the powershell script to run from the scripts folder.

Message -
Command is ./MTPdiir -Path Teensy
You cannot call a method on a null-valued expression.
At D:\ChuckW\Arduino\MTP_t4-master\MTP_t4-master\scripts\MTPdir.ps1:28 char:1

• echo @($C1.GetFolder.Items()).name

•   + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
  
  

PS D:\ChuckW\Arduino\MTP_t4-master\MTP_t4-master\scripts>

I really don't know anything about powershell...

if i use #include "mtp.h" the ide does not find the library file.
#include <MTP.h> works.

C:\Users\Frank\Documents\Arduino\libraries\MTP_t4-master\src\MTP.cpp:875:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation] 875 | if(!write_length_) dst=tx_data_buffer; write_length_ += len; | ^~ C:\Users\Frank\Documents\Arduino\libraries\MTP_t4-master\src\MTP.cpp:875:50: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if' 875 | if(!write_length_) dst=tx_data_buffer; write_length_ += len; | ^~~~~~~~~~~~~ Compiling library "USB2-master"

Desired scenario: My teensy code runs in different modes. When first connected, the mode is set to mtpMode and the SD card should be accessible from the PC. When the device is switched into a different program mode, the USB drive should no longer be accessible from the PC.

I attempted to do this by calling mtpd.loop() only when mode == mtpMode. Unfortunately, when I switch to another mode this causes Windows Explorer/ ThisPC (and other things) to hang forever. Presumably Explorer is blocked waiting for a response from mtpd.

Is there a way to accomplish this? Switching off the teensy causes Windows Explorer to close, which is the ideal desired behavior, but seems to be tied to USB teardown. I'd be satisfied with showing a drive that reported "access denied," or something else along those lines.

Using Teensy 4.1, Arduino 1.8.13, Teensy Loader 1.54-beta7.

map-test.ino prints contents of installed SDIO to terminal ok but nothing shows on on Mac file system.

Should the #include SD.h be updated or changed to sdfat.h?

Not sure why this just started popping up, but I'm getting a link error:

.pio/build/teensy41/src/main.cpp.o: In function `MTPStorageInterface::MTPStorageInterface()':
/home/mark/src/SOAR/SOAR-Code/SOAR-v2-Code/lib/MTP_t4/src/Storage.h:87: undefined reference to `vtable for MTPStorageInterface'
collect2: error: ld returned 1 exit status
*** [.pio/build/teensy41/firmware.elf] Error 1

Found the solution here: https://stackoverflow.com/a/57504289

It's a simple one to implement, so I submitted a pull request: #19

I do this now successfully as a hack, but it would be desirable to have some accepted or recommended method for passing reference(s).

Not sure if by design, but thought I would mention it;

At about line 45 we have:

#define DEBUG 1

I noticed it as I posted a data logger example on the New Teensyduino beta thread about LittleFs Datalogger, I did a quick and dirty add of MTP...

But then I was seeing debug output like:

1002 16 1 0:  1
1001 12 1 1: 
1014 16 1 2:  d402

Which I am pretty sure is from:

void MTPD::loop(void) 
  {
    usb_packet_t *receive_buffer;
    if ((receive_buffer = usb_rx(MTP_RX_ENDPOINT))) {
      printContainer();
      

The printContainer call.

The original library this was based on (https://github.com/yoonghm/MTP) was written to use SdFat.

Your comments here: https://github.com/WMXZ-EU/MTP_t4/blob/master/src/Storage.h#L24-L26 are unclear on your intent with regards to library support.

But the CURRENT revision looks like it has REMOVED SdFat support. Is this intentional? Is the use of SdFat discouraged now? I thought it was the preferred library to access files on an SD card on a Teensy; am I wrong? (I'm not an expert on this, I'm still figuring out the whole SD Card On Teensy space.)

I have tried really hard and cannot get this to work on a teensy 3.2. I have the latest version of Teensyduino, done all of the the mods as per instructions. It compiles the source files with no issues but is does not work like the original yoonghm/MTP code. It is not showing up in Windows explorer as a drive. Is there some place to set the CS pin? I am using the SPI and change made the changes for that. Can you help me out with some ideas?

Hello,
How can i use the library SD.h with the mtp activ ?
Actually MTP work great but i can't write or read files in arduino program :

Serial.print("Initializing SD card...");

  if (!SD.begin(BUILTIN_SDCARD)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");

return me initialisation fail if is after the following code

  #if !__has_include("usb_mtp.h") //
    usb_mtp_configure();          //
  #endif                          //
  storage_configure();

How can i use exemple like this :

File dataFile = SD.open(filn, FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(dataString1);
    dataFile.close(); 

Thx for help

PS: I use teensy 3.6

I am trying to compile mtp-test-ino for Teensy 3.6 using Arduino IDE + Teensyduino.

I get the error: 'FS' has not been declared in storage.cpp at this line:

void sd_addFilesystem(FS &fs, const char *name) {

I am using the following libraries:
Using library SD at version 1.2.2 in folder: /home/user/arduino-1.8.13/hardware/teensy/avr/libraries/SD
Using library Time at version 1.6 in folder: /home/user/arduino-1.8.13/hardware/teensy/avr/libraries/Time
Using library SPI at version 1.0 in folder: /home/user/arduino-1.8.13/hardware/teensy/avr/libraries/SPI

If I change #include "SD.h" to #include "SdFat.h" and use the SDFat V2 library from here https://github.com/greiman/SdFat, I get the same error.

What am I missing?

I have seen comments indicating that in some earlier version of the MTP it was possible to connect via a high-speed port rather than the 12 Mbps main port. There was some reference to an example, but I have not been able to find such an example. This would be highly desirable functionality.

The easiest way to replicate is using a very small text file e.g. "hello"

Some applications will only read the correct amount of data according to the file size, but some load in everything that the code sends, which might be a minimum of MTP_TX_SIZE packet

I think this might also happen with large files which are not exactly a multiple of MTP_TX_SIZE

It seems like all the code that sends out data will only do so once it hits a size that is a multiple of MTP_TX_SIZE
e.g.
https://github.com/WMXZ-EU/MTP_t4/blob/master/src/MTP.cpp#L959

This one seems like it sends too much, should probably send with size "len"?
https://github.com/WMXZ-EU/MTP_t4/blob/master/src/MTP.cpp#L1001

I am trying to unpick it all and I will send a PR if I can work it out but I'm struggling