Very impressive detective work! It is not a trivial manual to decipher.

I tried your program and it works pretty well. It gives me a couple of warnings in the printout, but it does not prevent from writing and reading a file.

What do you think is needed for insertion/removal detection to work? Is it something that should be handled in the ISR and given to a callback function?

What warnings are you getting?

I haven't looked at the code closely yet, so I can't say much about detection. I only know it's not working currently :)

I've never done a USB Host interface, but instinct tells me there ought to be a few Rs and Cs to correctly terminate the USB connection. Is there a published schematic with values?

The schematic is here, see page 2.

The warnings are probably due to some difference in the specific USB flash drive I'm using:

In Host_Init
Initializing Host Stack
Host Initialized
Connect a Mass Storage device
Mass Storage device connected
Successfully initialized mass storage interface; 1023999 blocks of size 512
Inquiry reply:
Peripheral device type: 00h
        - Direct access (floppy)
Removable Media Bit: 1
ANSI Version: 02h
        - warning! must be 0
ECMA Version: 00h
ISO Version: 00h
Response Data Format: 02h
        - warning! should be 1
Additional length: 1Fh
Vendor Information: 'Pretec  '
Product Identification: '512MB           '
Product Revision: '2.00'

List of files on the flash drive:
... 

Ah, interesting. Looks like your drive supports newer spec that what's available on the USB site. I guess I should make those checks to be "equals or greater", instead of "equals".

Hi Igor,

I did not mean the mbed schematics, but just the details of connecting the new Host USB connector to D- and D+. I would expect a resistor in between each mbed D pin and the USB connector pin, and a cap to ground from each active connector pin. But as I said I've never done a Host USB port before

If you check the schematics, you will see the resistors and caps you're talking about. Since they're already present on the mbed board, I guess no extra ones are necessary. I connected directly to the pins.

I did not realize that the mbed D- D+ pins are at connector end of  the series resistors.

Thanks

I've imported the code into my compiler, then compiled and stored on my mbed. When I reset my mbed, I get a short serial output followed by flashing siren lights:

================================
USB Mass storage demo program for mbed LPC1768
================================

In Host_Init
Initializing Host Stack
Host Initialized
Connect a Mass Storage device
ERROR: In Host_EnumDev at Line 385 - rc = -1
Could not enumerate device: -1
List of files on the flash drive:
Could not open d

Any idea why it cannot enumerate the device? What can I do to fix it?

The line in question (Line 385 in usbhost_lpc17xx.c) is this block of code:

rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_DEVICE, 0, TDBuffer, 8);
if (rc != OK) {
PRINT_Err(rc);
return (rc);
}

Could it be an issue with my USB drive?

Thanks :)

FYI - I've encountered the identical issue. I tried 4 different types of USB stick drives all with the same response.

Assuming the code was correct I fiddled with the USB connections.  This seemed to do the trick.

Have you tried this with a USB hard drive (not a flash stick)?

Wanting to use this code for logging a large amount of data, but wanted to know if I'm continuously writing to the flash disk - what would be the best way to go about doing this without wearing out the flash quickly ? I guess could put in a RAM buffer and then write a large block at a time, but then obviously this may be quite time consuming so ideally would like to log as AD samples are taken...Any ideas would be appreciated. Thanks!

hi , i tried using the code . but my mbed is just flashing led's ... can anyone help me with the connection schematics please . thanks !

Pleasde help in using the schematics. I am getting some error

I noticed that Cool components has a nice USB A breakout board, http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=556

They seem to be a bit hard to find elsewhere.

I have pulled down D+ and D- with 15K resistors for using as usb host, Power for USB I am taking from VU, But When I conneted to PC using USB connector MBED board is not detected by PC. MBED board is getting powered up. But it is not detected as Mass Storgae device Please help me to resolve this.

Jammulak.

HI,

How to load bin file into Mbed when using USB Host functionality. When D+ and D-  are pulled down with 15K resistors MBED is not detected as Storage device. Please help

This page is about connecting USB devices to mbed. If you're having problems with programming mbed itself, please post in the forums.

Hi Kiran,

If you are having problems with the mbed interface/mbed disk appearing whilst trying to use the LPC1768 USB interface on the D+ D- pins, make sure you really are connecting to those pins and not IF+/IF-. The behaviour you describe could be explained if you were connecting something to one or both of the IF+ and IF- pins; these are reserved and should not be connected, else the mbed interface may not function correctly.

Simon

Thanks Simon, it helped me to resolve the issuse.

When I am testing MSCUSBhost project I am getting up to Host initialization.

 ================================
USB Mass storage demo program for mbed LPC1768
================================

In Host_Init
Initializing Host Stack
Host Initialized
Connect a Mass Storage device

I am getting serial messages upto above. I am testing with mobile selected in Mass storgae mode. What could  be the problem

My USB device detection is very inconsistent. I have used some debug messages in USB isr but, those debug messgaes are not printed . Device is deteced once in 10 times.  Please help me.

Hello everyone,

I am using Igor's libraries and can write to different kind of USB flash drives.

The only problem I'm having is when I'm trying to write accelerometer data (800Hz) from 3-axis the file writing line is holding my code resulting in some data loss. I tried to store data in FIFO of accelerometer and then write them in a for loop so the USBfd have some time to process the data. Dropping the sample rate to lower value also didn't help. Tried different FIFO sizes but checking the interrupt pin it seems whatever I'm doing the file writing holds the code for around 240ms time to time. (repeating every 3s if FIFO size is 25, each axis value stored in 4byte float separated by tab)

I'am guessing it has to do something with the block size reaching a certain value and the USBfd needs that time to process the data.

The flash drive has been checked and should be able to reach around 9Mb/s writing speed.

Any suggestion how to overcome my problem?  Thanks in advance!

Don't write in small chunks, write into a buffer then write that to the flash drive. USB can have pretty good throughput but the latency is usually quite bad.

Note that Stéphane Bausseron found some bugs in the FATFilesystem that I use when writing more than 512 bytes: http://mbed.org/forum/mbed/topic/2273/

Thanks for the quick reply I will look into this!

I'm using the latest FATFileSystem where i have no access to the diskio.c file but since it's a later version I'am hoping that has been modified by now.

Your other suggestion about the larger chunks has some problems for me to. I have to collect data for a longer period of time so I would need two buffers one to fill until the other one can be written to the USBfd. The problem is (if I am wright) I can't do these functions in parallel.

Try this: use a Ticker to run a periodic task which would check how much data is in the buffer and flush when you have enough or when some time passed since the last flush. You might have to take some care to protect the buffer object from being modified simultaneously in the main program and the Ticker callback.

It is actually a good idea but I am having to short time to try this. Thinking of trying to recover the signal using the Real-Time Clock. Thanks for your advice anyway might be a good solution for a later project.

Hello,

Let me just ask something to ensure I understand it right. So whenever I write anything to the USB flash drive (or even SD-card), using command like fprintf() the mbed first just collects 512byte big data in its memory then when the block is ready then it sends it to the USB flash drive (or even SD-card)? Unless the data never gets that big and that case the mbed fills the rest with some dummy variable?

I am hoping to use this program to allow my mbed to store the data of my DUT into a USB stick. My mbed would not be connected to any computer during the experimentation. Would this program still work?

The mbed would be recording voltage and current reading within the range allowed by the mbed.

After the experimentation, I would not be connecting my mbed to the pc to transfer data but instead use the USB stick. The reason why I cannot connect my mbed directly to a computer is due to safety reason as the DUT cannot leave the lab and since the mbed is connected to it, it could not be removed.

hello,I am using this demo program. I added every .cpp\.h file in "USBHostLite" and "MSCFileSystem.h\.cpp". The compiler I am using is keil, during building the target, there always exist many errors, listed below: .\mbed\FileHandle.h(19): error:  #20: identifier "namespace" is undefined. I can't fix this bug, pls help.Thanks for your help.

jim hamblen wrote:

I noticed that Cool components has a nice USB A breakout board, http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=556

They seem to be a bit hard to find elsewhere.

Thanks for the picture. I'm using a PCB-mount connector and it was handy to have something to confirm the pinout against. It was that or wikipedia and on there they don't make it clear which way they are "looking".

where i have to connect the D+ and D- pins of usb to mbed in this programme?

I've got this going fine with one USB memory stick (thanks). Now I want to do it with two devices. Two questions arise:

1) On the face of it, the code is all written on the assumption that there will only ever be one device attached. Is there a good reason for this? It should be possible to enumerate through all the attached devices, but it looks like quite a rewrite, and much of the code is only lightly commented.

2) I can't find any definitive statement about whether one can connect two USB devices in parallel. As it's a master-slave device, I'd have thought it should work. Or do I need to use a hub? And what goes in a hub?

The two devices will initially both be mass storage, though one might be something else eventually.

Hello Sir, Please help me out in reading USB Mass storage device using mbed LPC1768. I have been using Igor skochinsky's code to read USB Mass storage Device using mbed LPC 1768 and it was working fine earlier(a month before). The code was able to display the USB enumeration data, list of files in USB mass storage device,read and write acknowledgement data. But now I am using the same code to read the USB,but I am unable to get the list of files in USB. I am just getting the following output in hyperterminal

=================================

USB Mass Storage Demo Program for mbed LPC1768

=================================

Reading USB memory

In Host_Init

Initialising Host Stack

Host Initialised

Connect a Mass Storage Device

I tried with the couple of other mass storage devices too,.its not working,.

Please help me out

Prashanth Shetty

prashanthshetty149@yahoo.com

I would be obliged if someone could look into this, too.  I don't think Prashanth has a hardware problem because my code started behaving the exact same way recently (both this and another USB application I've been using leveraging this library).  Oddly the code stops at the "Connect a Mass Storage Device" same as Prashant when the thumb drive is inserted but if the drive is removed (or wasn't there to begin with) the program continues and fails enumeration (see below).  This used to work.  I didn't update the library but I did recompile.  When I load an old bin file I compiled weeks ago, that works.

================================

USB Mass storage demo program for mbed LPC1768

================================

In Host_Init

Initializing Host Stack

Host Initialized

Connect a Mass Storage device  [Note(*) program freezes here until the thumbdrive is removed]

ERROR: In Host_EnumDev at Line 386 - rc = -1

ERROR: In Host_EnumDev at Line 387 - rc = 15856

Could not enumerate device: -1

List of files on the flash drive:

Could not open d

Nevermind.  Now it's working again for me.  Not sure what changed.  Probably flakey wiring and bad luck when it working briefly when I tried the old version coupled with similar sightings from others.

Tick Tock wrote:

Nevermind.  Now it's working again for me.  Not sure what changed.  Probably flakey wiring and bad luck when it working briefly when I tried the old version coupled with similar sightings from others.

Grey  wrote:

I've imported the code into my compiler, then compiled and stored on my mbed. When I reset my mbed, I get a short serial output followed by flashing siren lights:

================================
USB Mass storage demo program for mbed LPC1768
================================

In Host_Init
Initializing Host Stack
Host Initialized
Connect a Mass Storage device
ERROR: In Host_EnumDev at Line 385 - rc = -1
Could not enumerate device: -1
List of files on the flash drive:
Could not open d

Any idea why it cannot enumerate the device? What can I do to fix it?

 

The line in question (Line 385 in usbhost_lpc17xx.c) is this block of code:

rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_DEVICE, 0, TDBuffer, 8);
if (rc != OK) {
PRINT_Err(rc);
return (rc);
}

Could it be an issue with my USB drive?

Thanks :)

did anybody figure it out?

I would start by having a look at: http://mbed.org/handbook/USBHostMSD, that is way more recent.

Good morning, I have a crazy situation,

My MBED, in a coolcomponents dev board, AND my own PCB,

can read.write to the USB Memory stick,  **AFTER PROGRAMMING**

but when I power cycle MY PCB, (two of them) USB read.write stopps working !!

wheras, the 'real MBED' will work ??

The only thing I can think of is:

something happening in the MAGIC cchp?

Can anyone help, Realy need to get this going..

Cheers

**Ceri

printout from working boot & faild boot ...

//working

USB Mass storage demo program for mbed LPC1768

From: http://mbed.org/users/igorsk/code/MSCUsbHost/file/95e55809ecdb/main.cpp

================================

In Host_InitInitializing Host StackHost InitializedConnect a Mass Storage deviceMass Storage device connectedSuccessfully initialized mass storage interface; 30261247 blocks of size 512

Inquiry reply:nPeripheral device type: 00hn - Direct access (floppy)nRemovable Media Bit: 1nANSI Version: 02hn - warning! must be 0nECMA Version: 00hnISO Version: 00hnResponse Data Format: 02hn - warning! should be 1nAdditional length: 1FhnVendor Information: 'Imation 'nProduct Identification: 'Nano Pro        'nProduct Revision: 'PMAP'nIn Host_InitInitializing Host StackSpurious status change (connected)?Host InitializedConnect a Mass Storage deviceMass Storage device connectedSuccessfully initialized mass storage interface; 30261247 blocks of size 512

Inquiry reply:nPeripheral device type: 00hn - Direct access (floppy)nRemovable Media Bit: 1nANSI Version: 02hn - warning! must be 0nECMA Version: 00hnISO Version: 00hnResponse Data Format: 02hn - warning! should be 1nAdditional length: 1FhnVendor Information: 'Imation 'nProduct Identification: 'Nano Pro        'nProduc

List of files on the flash drive:

//broken

USB Mass storage demo program for mbed LPC1768

From: http://mbed.org/users/igorsk/code/MSCUsbHost/file/95e55809ecdb/main.cpp

================================

In Host_InitInitializing Host StackHost InitializedConnect a Mass Storage deviceMass Storage device connectedSuccessfully initialized mass storage interface; 30261247 blocks of size 512

Inquiry reply:nPeripheral device type: 00hn - Direct access (floppy)nRemovable Media Bit: 1nANSI Version: 02hn - warning! must be 0nECMA Version: 00hnISO Version: 00hnResponse Data Format: 02hn - warning! should be 1nAdditional length: 1FhnVendor Information: 'Imation 'nProduct Identification: 'Nano Pro        'nProduct Revision: 'PMAP'nIn Host_InitInitializing Host StackSpurious status change (connected)?Host InitializedConnect a Mass Storage deviceMass Storage device connectedSuccessfully initialized mass storage interface; 30261247 blocks of size 512

Inquiry reply:nPeripheral device type: 00hn - Direct access (floppy)nRemovable Media Bit: 1nANSI Version: 02hn - warning! must be 0nECMA Version: 00hnISO Version: 00hnResponse Data Format: 02hn - warning! should be 1nAdditional length: 1FhnVendor Information: 'Imation 'nProduct Identification: 'Nano Pro        'nProduc

List of files on the flash drive:

Error !! Could not open directory!  [E1]

Testing file write: