The commercial temperature range CC6 variants support only -25°C / 85°C with Sandisk eMMC.The industrial temperature range CC6 variants support -40°C / 85°C with Micron MTFC4GACAAAM-4M IT flash.Digi has performed reliability/endurance test of the Flash (only during device verification, not with each chip). We are writing into the flash utilizing the wear leveling and check when the first bad blocks appear.In the device verification, this was the case at more than 10.000 GByte data. This matches with normal MLC behavior, 2500 read/write cycles over the complete 4GB.
Comparing the Digi ConnectCore i.MX53 to the ConnectCore i.MX6 we see slightly improved values in flash endurance which is most likely due to using eMMC.eMMC Information
General Information on Multi Level Cell (MLC) vs. Single Level Cell (SLC) Technology
MLC NAND flash is a flash memory technology using multiple levels per cell to allow more bits to be stored using the same number of transistors. In single-level cell (SLC) NAND flash technology, each cell can exist in one of two states, storing one bit of information per cell.Most MLC NAND flash memory has four possible states per cell, so it can store two bits of information per cell. This reduces the amount of margin separating the states and results in the possibility of more errors.
Traditionally, each cell had two possible states, so one bit of data was stored in each cell in so-called single-level cells, or SLC flash memory. SLC memory has the advantage of faster write speeds, lower power consumption and higher cell endurance. However, because SLC memory stores less data per cell than MLC memory, it costs more per megabyte of storage to manufacture. Due to faster transfer speeds and longer life, SLC flash technology is typically used in high-performance and industrial applications.
eMMC used on CC6
eMMCs are built with MLC NAND flash chips. However, on the ConnectCore 6 module we are currently using eMMC version 4.41 or higher for which the "enhanced user area" is possible.
Enhanced user area stands for "emulating SLC". This also means that usable memory space is reduced by half, e.g. a 4GByte eMMC represents only 2GByte of "enhanced user area" space.
eMMC Health Information Feature
For applications requiring memory health status information, the “Device Health Report” feature would be interesting . This is supported from JEDEC revision 5.0 onwards.
Currently (2015 April), we do not have any eMMC 5.0 components approved for CC6
Last updated: Oct 05, 2017