XC888LM datasheet(62/144 Pages) INFINEON

62 / 144 page

XC886/888CLM

Functional Description

Data Sheet

V0.9, 2006-12

3.3.3

Flash Programming Width

For the P-Flash banks, a programmed wordline (WL) must be erased before it can be

reprogrammed as the Flash cells can only withstand one gate disturb. This means that

the entire sector containing the WL must be erased since it is impossible to erase a

single WL.

For the D-Flash bank, the same WL can be programmed twice before erasing is required

as the Flash cells are able to withstand two gate disturbs. This means if the number of

data bytes that needs to be written is smaller than the 32-byte minimum programming

width, the user can opt to program this number of data bytes (x; where x can be any

integer from 1 to 31) first and program the remaining bytes (32 - x) later. Hence, it is

possible to program the same WL, for example, with 16 bytes of data two times (see

Figure 12)

Figure 12

D-Flash Programming

Note: When programming a D-Flash WL the second time, the previously programmed

Flash memory cells (whether 0s or 1s) should be reprogrammed with 0s to retain

its original contents and to prevent “over-programming”.

0000 ….. 0000

32 bytes (1 WL)

1111 ….. 1111

0000 ….. 0000

16 bytes

0000 ….. 0000

1111 ….. 1111

Flash memory cells

32-byte write buffers

1111 ….. 0000

1111 ….. 1111

0000 ….. 0000

1111 ….. 0000

Program 1

Program 2

Note: A Flash memory cell can be programmed

from 0 to 1, but not from 1 to 0.

XC888LM Datasheet(PDF) 62 Page - Infineon Technologies AG