Data Sheet

14
5. Block Diagram and Function Explanations
5.1 Block Diagram
5.2 Function Explanations
5.2.1 Global Wear Leveling Function
Global wear leveling ensures that every block has an even erase count. This helps to extend the life
expectancy of an SSD.
There are three main processes in global wear leveling:
(1) Record the block erase count and save this in the wear-leveling table.
(2) Find the static-block and save this in the wear-leveling pointer.
(3) Check the erase count when a block is pulled from the pool of spare blocks. If the block erase count is
larger than WEARCNT, then swap the static-block and the over-count-block.
5.2.2 Bad Block Management Function
When the flash encounters ECC fail, program fail or erase fail, the controller will mark the block as a bad
block. This will prevent the usage of bad blocks which may result in data loss in the future.
5.2.3 Enhanced S.M.A.R.T. function
Transcend SSD supports S.M.A.R.T. command (Self-Monitoring, Analysis, and Reporting Technology) that
allows users to read the health information of the SSD. Transcend also define some innovated S.M.A.R.T.
features which allows the user to evaluate the status of the SSD in a much more efficient way.
5.2.4 StaticDataRefresh Technology
Normally, ECC engine corrections are taken place without affecting the host normal operations. As time
passes by, the number of error bits accumulated in the read transaction exceeds the correcting capability
of the ECC engine, resulting in corrupted data being sent to the host. In order to prevent such occurrence,