SLUFD128MU1U-A STEC, SLUFD128MU1U-A Datasheet - Page 8

• Manufacturer Part Number: SLUFD128MU1U-A
• Manufacturer: STEC
• Type: USB Flash Driver

Specifications of SLUFD128MU1U-A

• Density: 128MByte
• Operating Supply Voltage (typ): 5V
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Package Type: Not Required
• Mounting: Socket
• Pin Count: 4
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (max): 5.25V
• Programmable: Yes
• Lead Free Status / RoHS Status: Compliant

SLUFDxxx(M/G)U1U(I)-y
Industrial Grade USB Flash Drive
Datasheet
that with every write to the flash, the youngest block is used. This ensures that the full flash media is
used uniformly, so that one area of the flash will not reach the endurance limits prematurely before
other areas. The implemented wear leveling algorithm ensures a minimum of 2 million write/erase
cycles for the entire flash media.
3.2.3 Error Correction/Detection
The USB 2.0 controller implements an advanced Error Correction/Detection scheme, based on the
Reed-Solomon algorithm. The ECC engine can detect up to 5 bytes and correct up to 4 bytes per
512 bytes (symbol based). To ensure the fastest performance, both detection and correction are
done on-the-fly, in hardware only.
Each time the host application writes a sector of 512 bytes to the Industrial Grade UFD, a unique
ECC signature is created by the ECC engine and written together with the data to the flash. When
the data is read back by the host, the ECC engine creates again a unique ECC signature. It will then
compare the original written signature with the newly created signature, and sets an error flag if the
two signatures are not the same. Correction of the data is done on-the-fly when the error flag is set,
and the data presented to the host will be the same as the original written data. This powerful Error
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Correction/Detection scheme results in an overall error rate of less than 1 in 10
bits, read.
3.2.4 Power Failure Management
The embedded flash management software uses algorithms that ensure data integrity, even during
power failures. After each write, a verify write flag is set in the extra area of the flash page, while a
dismount flag is set for the whole device during regular power-down. When a power failure occurs,
both the verify write and the dismount flag will not be set, indicating a power failure during a write or
erase operation. Upon the next power-up, the mapping tables will be reconstructed from the
information stored in the flash memory, and the last version of the sector with a correct verify write
flag will be used.
This mechanism ensures complete data integrity. When writing, copying, or erasing the flash device,
the data format remains valid at all intermediate stages. Old data is never erased until the verify write
flag of the new sector has been set. Therefore, a data sector cannot exist in a partially written state.
The operation is either successfully completed (verify write flag is set) and the new data is valid, or
the operation has not yet been completed or has failed, in which case the old sector contents remain
valid.
61000-04536-105, May 2007
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