White Papers
How to Interface a USB Flash Drive to a Microcontroller
How to Design an Embedded System with USB Flash Drive Support
The removable USB flash drive is a key technology in the embedded computing world. Among other things, it can be used to store and transfer logged data, back up a device’s settings, or be a vehicle to update a deployed device’s firmware. When you need to transfer data from a microcontroller-based embedded system to a PC (or vice versa), using a portable memory device, like a USB flash drive, is a convenient method, especially when transferring data over a network is not possible or desirable.
Although USB flash drives are easy to use, designing a microcontroller-based embedded system that supports the use of these devices can be a challenging task, especially when you don't know what you don't know. This 17-page white paper provides embedded systems designers with the key concepts and considerations needed to successfully incorporate a USB host into a microcontroller-based embedded design, such that USB flash drives can be used for a host of applications.
Table of Contents
- Introduction
- An Overview of the Universal Serial Bus (USB)
- Designing the System
- Make/Buy
- Compliance Testing
- Implementation Overview
- USB Host Controller Choices
- USB Software Support
- Designing Custom USB Hardware
- USB Connectors
- Power Supplies
- Resets & Brownout
- Electromagnetic Interference (EMI)
- Controlled Impedance
- Example Host Controller Solutions
- Example Bolt-On Host Controller
- Example Built-In Host Controller
- Implementing the Embedded Firmware
- The USB Flash Drive File System
- Handling Surprise Removal and Power Loss
- File System Licensing
- About Datakey
- Conclusion
- Glossary
- References