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I want to develop mass storage device using LPC2148.I am just referring code from Keil for USBMem. My problem is - I get Get_descriptor command from PC to which I respond with device descriptor. On receiving 8th byte it generates Reset. Then I get Set_address command. On response to it, I execute Set Address command in protocol engine. Then again I get Get_descriptor command (It should actually have index field of 18 but I receive with 64). Again after 8th byte it generates Reset and again gives Set_address command instead of Get_descriptor command for Configuration descriptor. What can be the problem?
> What is sequence of next requests from host?
For device firmware, you should not expect requests in sequence. Host puts any request as it likes. Device responds to it and does the requested job, if the device supports it. Otherwise, the device returns STALL.
> As mine is mass storage device, can you please tell me what events are expected further.
Ummm MSC (Mass Storage Class), It's really tough for starter, because you have to implement two layers of protocol. I recommend HID for the starting project, which is simpler.
But if you dare to try MSC, Read out the MSC specs I refer in this post. Also, Jan Axelson's book, USB Mass Storage ( http://www.lvr.com/usbms.htm ) is your friend. Trace a successful implementation, like LPCUSB lpcusb.svn.sourceforge.net/.../msc_bot.c lpcusb.svn.sourceforge.net/.../msc_scsi.c And then, attack to the implementation.
For MSC Bulk-Only Transport (BOT) implementation, Firstly, you have to implement the handlers for required class-specific request(s) at least, in addition to the standard device requests. Secondly, MSC-BOT carries SCSI command over bulk IN/OUT endpoints with command wrapper packets. You have to unwrap/wrap SCSI command and status, and transfer requested data or media sector (cluster) data Thirdly, SCSI command parser upon above MSC-BOT protocol, which handles the media actually.
1. Class specific request
these USB specs are the must.
Mass Storage Class Specification Overview 1.3 www.usb.org/.../usb-msc-overview-1.3b.pdf
Mass Storage Bulk Only 1.0 www.usb.org/.../usbmassbulk_10.pdf
In "3 Functional Characteristics (usbmassbulk_10.pdf p7)" section, you'll find these class-specific requests. - 3.1 Bulk-Only Mass Storage Reset (class-specific request) - 3.2 Get Max LUN (class-specific request)
"Bulk-Only Mass Storage Reset" is required, but "Get Max LUN" is optional for single-LUN device. If you don't implement "Get Max LUN", return STALL to this request.
Other than these class-specific requests, these standard requests are used for error recovery. - Get_Status( ENDPOINT ) (usb_20.pdf 9.4.5 Get Status) - Clear_Feater( ENDPOINT_HALT ) (usb_20.pdf 9.4.1 Clear Feature)
USB 2.0 spec www.usb.org/.../usb_20_122909-2.zip
2. Command/Data/Status Protocol over bulk IN/OUT endpoints
1) Command transport SCSI command comes to bulk OUT EP included in Command Block Wrapper (CBW) (usbmassbulk_10.pdf 5.1 Command Block Wrapper (CBW)) Check the integrity of the CBW following to "6.2 Valid and Meaningful CBW" section. If it isn't valid, return STALL to bulk IN EP, following "6.6.1 CBW Not Valid" For valid CBW, pass the SCSI command to the parser. Depending on the SCSI command, MSC-BOT handler moves to one of Data In/ Data Out / Status transport stage.
2) Data IN/Out transport Most of SCSI command exchange data on this stage. For example, Inquiry returns fixed inquiry response (a block of data) to bulk IN EP. Read(10)/Write(10) exchange block data (sector - 512 bytes or cluster - 4K bytes) over bulk IN/OUT EP. But some SCSI commands, like Test Unit Ready, don't have this stage.
3) Status transport All of SCSI commands conclude the session in this stage. Firmware passes back Status report (the result of the SCSI command), included in Command Status Wrapper (CSW), to the bulk IN EP.
3. SCSI command over above MSC protocol
The required SCSI commands are listed up in "4.2 Command Set Information" (PDT=00h) section of this spec.
MSC Compliance Test Specification www.usb.org/.../MSC-compliance-0_9a.pdf
required SCSI commands - Inquiry - spc3r23.pdf(p142) - Request Sense - spc3r23.pdf(p221) - Test Unit Ready - spc3r23.pdf(p232) - Read(10) - sbc2r16.pdf(p47) - Read Capacity(10) - sbc2r16.pdf(p54) - Write(10) - sbc2r16.pdf(p78)
Implement them all following the SCSI spec. As of these SCSI specs, the original t10.org has closed the links just for their members. Search "sbc2r16.pdf" on Goooogle, and you'll find them floating over the internet. This is just a brief outline of MSC-BOT and SCSI implementation. You'll learn a lot from a running example, the specs and the reference book.
Good luck.
Tsuneo
Implementing class requests for mass storage class. Got GET MAX LUN request. Replied it with value zero. using bus hound software. so my device replies with 1 byte that is 0. but host does not respond. why is this so?
Uho, you are actually attacking to MSC implementation. Impressed with your guts. > Got GET MAX LUN request. Replied it with value zero. using bus hound software. so my device replies with 1 byte that is 0. but host does not respond.
Ah, you are trapped with Get_Max_LUN pitfall. Maybe you weren't aware of this sentence on the MSC-BOT spec. www.usb.org/.../usbmassbulk_10.pdf
3.2 Get Max LUN (class-specific request) The device shall return one byte of data that contains the maximum LUN supported by the device. For example, if the device supports four LUNs then the LUNs would be numbered from 0 to 3 and the return value would be 3. If no LUN is associated with the device, the value returned shall be 0. ... Devices that do not support multiple LUNs may STALL this command.
That is, for single LUN, you have to return STALL Surely, it's confusing. ;-) I've seen many ones also have been trapped.
To return STALL to IN EP0, put this protocol engine command. - Set_Endpoint_Status (IN EP0: 0x00410500, ST bit: 0x00010100)
When next SETUP transaction comes, STALL is cleared automatically by the protocol engine.
1. I stalled control IN endpoint. I got clear_feature command then. I replied to it just by executing Set_Endpoint_Status (IN EP0: 0x00410500, ST bit: 0x00000100) and sent zero length packet. When i analyzed Bus hound, host does not respond after clear_feature. It again asks 1. Get max lun 2. Clear_feature and does it for 3 times to Reset the device. What should i do?
2. I am getting string descriptor request for language id and serial no. but not for manufacturer string. I checked for device descriptor index fields. it seems to be fine. What can be the problem?
> 1. I stalled control IN endpoint. I got clear_feature command then.
Ummm... Clear_Feature is unexpected response. For protocol STALL on default endpoint, Clear_Feature is not issued. Clear_Feature is used for recovery of bulk/interrupt endpoint.
a) Which endpoint does the Clear_Feature points, Post the 8 byte SETUP data of the Clear_Feature
b) Do you see any other bus activity between Get_Max_LUN and Clear_Feature on bus hound? Does the host happen to send CBW to bulk OUT endpoint?
Which endpoint does the Clear_Feature points, Post the 8 byte SETUP data of the Clear_Feature
important fields of setup packet are -> recipient - endpoint endpoint no - 0 feature - endpoint_halt
on bus hound we found in following sequence GetMaxLun(3 times) Stall pid Clear feature(3) cancelled Reset(3) no response
We have not yet written structure for CBW. There is no interrupt on bulk endpoints.
> endpoint no - 0
Do you mean OUT EP0 ? wIndex = 0x0000 : OUT EP0, 0x0080 : IN EP0
It's better to show the 8-bytes SETUP data of the request directly, than giving the interpreted value. On Bus Hound log, You'll see the original SETUP data. It's more reliable evidence. Anyway, host should be satisfied by both of these device responses. - Return 1 byte of 0 on data stage to Get_Max_LUN request - STALL to Get_Max_LUN request
I investigated more on this issue, and found this sentence on the compliance test spec.
MSC Compliance Test Specification www.usb.org/.../MSC-compliance-0_9a.pdf - Class-Specific Request Assertions 5.5.2 If the device supports only one LUN, it may report so via the Get Max LUN request or may fail that request.
Also, I observed enumeration of six USB memories on a hardware analyzer. All of them returns "0" to Get_Max_LUN. Did you "realize" the bulk IN/OUT endpoints on the handling of Set_Configuration request ? These bulk EPs should be "realized" like the default EP. Sound like the error is caused by disabled bulk EPs
I was realizing bulk endpoints one after the other. i.e. USBReEp=0x00000010 USBReEp=0x00000020 That i changed to USBReEp=0x00000030. And i got bulk OUT interrupt.
Could not save the bus hound file but details are - GetMaxLun(2) stall pid CLEARFEATURE(2) -> data - 02 01 00 00 00 00 00 00 canceled -> data - c0010000 no response -> data - c0000005 RESET(2) ok USBCBW
This is bus hound file
Bus Hound 6.01 capture on Windows XP Service Pack 2 (x86). Complements of http://www.perisoft.net bulkoutint Device - Device ID (followed by the endpoint for USB devices) (28) USB Mass Storage Device Phase - Phase Type CTL USB control transfer RESET bus reset IN Data in transfer USTS USB status NTSTS NTSTATUS value ok command complete OUT Data out transfer Data - Hex dump of the data transferred Descr - Description of the phase Delta - Elapsed time from the previous phase to the current phase Cmd... - Position in the captured data Device Phase Data Description Delta Cmd.Phase.Ofs(rep) ------ ----- -------------------------------------------------- ---------------- ----- ------------------ 28.0 CTL 80 06 00 01 00 00 12 00 GET DESCRIPTOR 26sc 1.1.0 28.0 IN 12 01 00 02 00 00 00 40 .......@ 3.6ms 1.2.0 28.0 CTL 80 06 00 02 00 00 09 00 GET DESCRIPTOR 36us 2.1.0 28.0 IN 09 02 20 00 01 01 01 60 .. ....' 3.9ms 2.2.0 28.0 CTL 80 06 00 02 00 00 20 00 GET DESCRIPTOR 32us 3.1.0 28.0 IN 09 02 20 00 01 01 01 60 .. ....' 3.9ms 3.2.0 28.0 CTL 80 06 00 03 00 00 02 00 GET DESCRIPTOR 28us 4.1.0 28.0 IN 04 03 .. 3.9ms 4.2.0 28.0 CTL 80 06 00 03 00 00 04 00 GET DESCRIPTOR 28us 5.1.0 28.0 IN 04 03 09 04 .... 3.9ms 5.2.0 28.0 CTL 80 06 0c 03 09 04 02 00 GET DESCRIPTOR 25us 6.1.0 28.0 IN 1a 03 .. 3.9ms 6.2.0 28.0 CTL 80 06 0c 03 09 04 1a 00 GET DESCRIPTOR 27us 7.1.0 28.0 IN 1a 03 41 00 42 00 43 00 ..A.B.C. 3.9ms 7.2.0 28.0 CTL 00 09 01 00 00 00 00 00 SET CONFIG 34us 8.1.0 28.0 CTL 01 0b 00 00 00 00 00 00 SET INTERFACE 38ms 9.1.0 28.0 CTL a1 fe 00 00 00 00 01 00 GET MAX LUN 39ms 10.1.0(3) 28.0 USTS c0000004 stall pid 4.3ms 10.2.0 28.0 CTL 02 01 00 00 00 00 00 00 CLEAR FEATURE 27us 11.1.0(3) 28.0 USTS c0010000 canceled 5.0sc 11.2.0 28.2 USTS c0000005 no response 10sc 16.1.0 28 RESET 68us 17.1.0 28 ok 188ms 17.2.0 28.2 OUT 55 53 42 43 08 e0 6f 89 USBC..o. 1.9ms 18.1.0 28 RESET 19sc 19.1.0(3) 28 NTSTS c000009c device data err 5.1sc 19.2.0
We are studying SCSI commands. Now our device appears as removable disk in my computer. Thank you!!! Having problem in answering Read capacity command.
What can be the cause of delay betweem Get_Max_LUN and next command? It is 5sec and then 10 sec.
We were successful in removing that delay. But still not able to respond READ CAPACITY. It gives error 'Time out'. What is meaning of this error? We have written handler for it.
Current status -> I am stuck at same position. This is bus hound file -
Device Phase Data Description Delta Cmd.Phase.Ofs(rep) ------ ----- -------------------------------------------------- ---------------- ----- ------------------ 28.0 CTL 80 06 00 01 00 00 12 00 GET DESCRIPTOR 6.7mn 1.1.0 28.0 IN 12 01 00 02 00 00 00 40 .......@ 3.2ms 1.2.0 28.0 CTL 80 06 00 02 00 00 09 00 GET DESCRIPTOR 30us 2.1.0 28.0 IN 09 02 20 00 01 01 01 60 .. ....' 3.9ms 2.2.0 28.0 CTL 80 06 00 02 00 00 20 00 GET DESCRIPTOR 27us 3.1.0 28.0 IN 09 02 20 00 01 01 01 60 .. ....' 3.9ms 3.2.0 28.0 CTL 00 09 01 00 00 00 00 00 SET CONFIG 34us 4.1.0 28.0 CTL 01 0b 00 00 00 00 00 00 SET INTERFACE 40ms 5.1.0 28.0 CTL a1 fe 00 00 00 00 01 00 GET MAX LUN 39ms 6.1.0 28.0 IN 00 . 3.8ms 6.2.0 28.2 OUT 55 53 42 43 08 50 67 89 /* CBW without RESET * USBC.Pg. 1.9ms 7.1.0(2) 28.2 IN 00 80 00 02 1f 80 00 00 ........ 1.9ms 8.1.0(2) 28.2 IN 55 53 42 53 08 50 67 89 USBS.Pg. 2.0ms 9.1.0(2) 29 CMD 12 00 00 00 24 00 INQUIRY 68ms 13.1.0 29 IN 00 80 00 02 1f 80 00 00 ........ 5us 13.2.0 29 CMD 25 00 00 00 00 00 00 00 READ CAPACITY 6.0ms 14.1.0 29 SSTS 09 timeout 9.0sc 14.2.0 28 RESET 68us 15.1.0 28 ok 186ms 15.2.0 29 CMD 25 00 00 00 00 00 00 00 READ CAPACITY 810ms 16.1.0 28.2 OUT 55 53 42 43 c0 92 3b 89 USBC..;. 1.8ms 17.1.0 28.2 IN 00 00 00 1f 00 00 02 00 ........ 1.9ms 18.1.0 28.2 IN 55 53 42 53 c0 92 3b 89 USBS..;. 1.9ms 19.1.0 29 IN 00 00 00 1f 00 00 02 00 ........ 7us 16.2.0 29 CMD 28 00 00 00 00 00 00 00 READ 20us 20.1.0 28.2 OUT 55 53 42 43 c0 92 3b 89 USBC..;. 1.9ms 21.1.0 28.2 IN 00 00 00 1f 00 00 02 00 ........ 2.0ms 22.1.0 28.2 IN 55 53 42 53 c0 92 3b 89 USBS..;. 999us 23.1.0 29 IN 00 00 00 1f 00 00 02 00 ........ 6us 20.2.0 29 SSTS 52 data overrun 3us 20.3.0 29 CMD 28 00 00 00 00 00 00 00 READ 496ms 24.1.0 29 SSTS 49 timeout 9.4sc 24.2.0
I am not getting mass storage class reset at all. Even before 1st CBW, there is no reset. SCSI commands continue to come. So i don't get whether i have answered command properly or not.
Now, when i connect my LPC2148 board to PC, i get 'Disk in drive is not formatted. Do you want to format it now?'. And if i say, yes. Then it says, 'Disk in drive can't be formatted'. What is its meaning?
> Now, when i connect my LPC2148 board to PC, i get 'Disk in drive is not formatted. Do you want to format it now?'. And if i say, yes. Then it says, 'Disk in drive can't be formatted'. What is its meaning?
It means no partition structure (Master Boot Record, boot sector etc.) is assigned on your "disk". For "RAM" (SD card) based disk, make partition(s) on the disk before formatting. DOS command, FDISK, or Windows disk management does the job. www.vistarewired.com/.../how-to-resize-a-partition-in-windows-vista
For "ROM" based disk, you have to give the contents of the disk with your program code.
You'll find such a file in many USB examples
Keil "LPC2148 USB Mass Storage Device Example" - DiskImg.c http://www.keil.com/download/files/lpc2148_usbmem.zip
Microchip USB examples - Microchip Application Libraries v2010-02-09 ww1.microchip.com/.../MCHP_App_ Lib v2010_02_09_Installer.zip C:\MicrochipSolutions\USB Device - Mass Storage - Internal Flash\Firmware\Files.c
Microchip one is better than Keil's, because it has many comments.
To realize the FAT format, this MS FAT spec is required. "Microsoft Extensible Firmware Initiative FAT32 File System Specification" www.microsoft.com/.../fatgen.mspx