1. USB 2.0 to SD-Card File Transfer
By: Nadav Haklai & Noam Rabinovici
Supervisors: Mike Sumszyk & Roni Lavi
Semester: Spring 2010

2. Project Goal Create a prototype for file transfer system.
Implement a stand alone bridge between USB and SD-Card interfaces.
Design a platform for future file transfer developments.
Learn the USB and SD-Card protocols.

3. System Definition: Copy files between USB and SD card devices.
Stand-alone device.
Support FAT file systems.
Easy to use user interface.
Low power – self powered (battery) .
Fast transfer rates - USB 2.0.
Low cost product.

4. Prototype Constrains:
Altera DE-3 Development Board
High power – Power supply.
Large dimensions.
Lower transfer rates – generic FPGA.
Very expensive.
Short development time and resources
Using open-source code (FAT).
Using Altera examples as skeleton.

5. Prototype System Architecture:
DE3 Board
USB 2.0 Port
ISP1761
(USB Controller)
Stratix III
Leds and switches
PIO Controller
ISP1761 Controller
Nios II Soft Processor
Avalon Switch Fabric
Console
JTAG
PIO Controller
On Chip Memory
SD Card Connector

6. Development Tools Software: Hardware: Quartus II 10.0 SOPC Builder
NIOS II IDE 10.0
Hardware:
Altera DE3 Board
Stratix III FPGA
Soft NIOS II Core
USB Controller - ISP1761
Signal Analyzer
USB Analyzer

7. Software Architecture:
Control Layer
NIOS II PIO
ISP 1761 HAL
USB HOST Controller
USB Protocol
USB mass storage device Driver
FAT File System
Main Program – User Interface
SD-Card Driver
Files Layer
512 Bytes Blocks Layer
Physical Layer

8. Technical Background:
USB 2.0- Standard for peripheral devices
The USB mass storage device class
ISP single-chip Hi-Speed Universal Serial Bus (USB) On-The-Go (OTG) Controller
SD-Card - Non-Volatile memory card format
Very popular and common (Cameras, Embedded Systems)
Fat - File System

9. USB 2.0
Definition: A specification to establish communication between devices and a host controller.
Main Uses
Device Classes
Mass Storage Device
Human Interface Device (HID)
Physical Layer
Host/Device Topology

10. USB Mass Storage Class USB Protocol - UFI Layer USB Floppy Interface
USB method for file transfers
Based on SCSI Commands
Data packet encapsulation
Uses USB low level driver

11. USB Mass Storage Class USB UFI level Implementation main commands:
Write Command:
Read Command:

12. USB Mass Storage Class USB Bulk level : Command/Data/Status Flow:
Command Status/Block Wrapper
Packet structure:

13. USB Mass Storage Class USB Write Function Structure
This function writes 512Bytes block using the USB.
Request from the file system to write 512B logical block
USBDISK_WriteBlock512
Request from the file system to write a physical block (equal or less than 512B)
USBDISK_ BOT_Write10
USBDISK_ BOT_execute
Sending the command to the device, same to read & write
Port_BulkIN
Port_BulkOut
Port_AltOut
Port_AltIn
Changing datagram with the device

14. Technical Background:
USB 2.0- Standard for peripheral devices
The USB mass storage device class
ISP single-chip Hi-Speed Universal Serial Bus (USB) On-The-Go (OTG) Controller
SD-Card - Non-Volatile memory card format
Very popular and common (Cameras, Embedded Systems)
Fat - File System

15. SD-Card SD-Card Protocol SD Mode (1 or 4bits) vs. SPI Mode
Bus Protocol basic operation:
Command Packet Format
Data Packet Format

16. SD-Card
SD-Card Implementation:
Initialization flow:

17. SD-Card
SD-Card Implementation:
Write Flow:
Read Flow:

18. SD-Card SD-Card Write Function Structure: SD_write_block send_cmd
Request from the file system to write 512B logical block
SD_write_block
Sending the command
send_cmd
SD_CLK_HIGH
executing the command
SD_CLK_LOW
SD_CMD_HIGH
SD_CMD_LOW
SD_DAT0_HIGH
SD_DAT0_LOW

19. Technical Background:
USB 2.0- Standard for peripheral devices
The USB mass storage device class
ISP single-chip Hi-Speed Universal Serial Bus (USB) On-The-Go (OTG) Controller
SD-Card - Non-Volatile memory card format
Very popular and common (Cameras, Embedded Systems)
Fat - File System

20. FAT File System
A method of storing and organizing computer files and their data
FAT Fundamentals:
Sectors and Clusters
Volume Structure:
MBR:

21. FAT File System Implementation – Open Source File System Support for:
SD-Card
USB – Mass Storage Device
Application Interface:
f_mount - Register/Unregister a work area
f_open - Open/Create a file
f_write - Write file
f_read - Read file
f_opendir - Open a directory
f_getfree - Get free clusters

22. FAT File System Files organization on storage device
Cluster Chains example

23. Technical Background:
USB 2.0- Standard for peripheral devices
The USB mass storage device class
ISP single-chip Hi-Speed Universal Serial Bus (USB) On-The-Go (OTG) Controller
SD-Card - Non-Volatile memory card format
Very popular and common (Cameras, Embedded Systems)
Fat - File System

24. Encountered Difficulties:
SD Card:
Signals Timing issues – Driver development.
USB:
Software bugs in the Terasic DE-3 examples code.
FAT:
Had to search for reliable open source code.
Complex integration of the FAT and the interfaces.

25. From Prototype to Product:
ASIC vs. FPGA
Board Design
Increase SD Card throughput
Support for different memory cards
USB 3.0
NTFS File system support
Low power design considerations
User interface
Product package

26. Thank You
Questions?