USB Handy Flash Drive
AP-HAxxxXX13XG-XX
3
©2015 Apacer Technology, Inc. Rev. 1.7
1. General Description
Apacer’s USB FLASH Drive (UFD) is a high performance flash disk drive designed offering portable
storage solutions. UFDs can be plugged into a standard USB 2.0 connector commonly found in desktops,
portable computers and even enterprise PC systems. Apacer’s UFDs have an efficient built-in
microcontroller and file management firmware that ensures ideal performance, functionality and reliability.
This product is well suited for portable flash storage applications while operating at minimal power
consumption.
1.1 Performance-optimized USB Controller
The heart of an UDM is the USB controller, which translates standard USB signals to the flash media and
controls the data in/out between the controller itself and the flash media. This proprietary USB controller is
specifically designed to attain high data throughput from host to flash.
1.1.1 Error Correction Code (ECC)
The UDM uses BCH Error Detection Code (EDC) and Error Correction Code (ECC) algorithms which
correct up to 24 random single-bit errors for each 1024-byte block of data.
1.1.2 Wear-Leveling
Flash memory can be erased a limited number of times. In a typical application, and especially if a file
system is used, specific pages are constantly updated (e.g., the page that contains the FAT, registry, etc.).
Without any special handling, these pages would wear out more rapidly than other pages, reducing the
lifetime of the entire flash. To overcome this inherent deficiency, Apacer’s USB-Disk Module (UDM) uses
wear-leveling algorithm. This wear-leveling algorithm ensures that consecutive writes of a specific sector
are not written physically to the same page in the flash. This distributes flash media usage evenly across
all pages, thereby maximizing flash lifetime. The wear-leveling mechanism provides write/erase cycles for
reliable data storage over an extended period.