XC2000 datasheet(81/647 Pages) INFINEON

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XC2000 Derivatives

System Units (Vol. 1 of 2)

Memory Organization

Preliminary

User’s Manual

3-19

V1.0, 2007-06

MemoryX2K, V1.1

•

Drain Disturb: Because of using a so called “one-transistor” flash cell each program

access disturbs all pages of the same sector slightly. Over long these “drain disturbs”

make 0 and 1 values indistinguishable and thus provoke read errors. This effect is

again interrelated with the retention. A cell that incurred a high number of drain

disturbs will have a lower retention. The physical sectors of the flash array are

isolated from each other. So pages of a different sector do not incur a drain disturb.

This effect must be therefor considered when the page erase feature is used.

The durations of programming and erasing as well as the limits for endurance, retention

and drain disturbs are documented in the data sheet.

Attention: No means exist in the device that prevent the application from violating

these limitation.

Array Structure

The flash memory is hierarchically structured:

•

Block: A block consists of 128 user data bits (i.e. 16 bytes) and 9 ECC bits. One read

access delivers one block.

•

Page: A page consists of 8 blocks (i.e. 128 bytes). Programming changes always

complete pages.

•

Sector: A sector consists of 32 pages (i.e. 4096 bytes). The pages of one sector are

affected by drain disturb as described above. The pages of different sectors are

isolated from each other.

•

Array: Each array has in the XC2000 64 sectors1). Usually when referring to an

“array” this contains as well all accompanying logic as assembly buffer, high voltage

logic and the digital logic that allows to operate them in parallel.

•

Memory: The complete flash memory of the XC2000 consists of 3 flash arrays.

This structure is visualized in Figure 3-5.

In the Flash0 one sector is reserved for device internal purposes. It is not accessible by software.

XC2000 Datasheet(PDF) 81 Page - Infineon Technologies AG