M35B32 datasheet(14/44 Pages) STMICROELECTRONICS

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Memory organization

M35B32

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Memory organization

The memory is organized as pages (256 bytes each), with a specific mapping shown in

Figure 5.

The M35B32 decodes addresses from 0000h up to 0FFFh. This makes an address range of

4 Kbytes organized as 16 pages of 256 bytes. The M35B32 can also be seen as two sectors

(the Data sector and the Event sector) which boundary is defined by the BPi status register

bits.

•

The Data sector (standard EEPROM) is at the top,

•

The Event sector (offering a fast programming time tFP) is at the bottom. The Event

sector can be also write-protected with pin W.

Both sectors can be erased in a single cycle, with the help of the Sector Erase instruction;

however, each page can be erased using the Page Erase instructions (recommended for

the Data sector).

Figure 5. Memory organization

1. N is defined by the BPi bits (see Section 6.4.3).

Each page can be individually:

•

programmed (bits are programmed from 1 to 0),

•

erased (bits are erased from 0 to 1),

•

written (bits are changed to either 0 or 1).

When the Page Program instruction addresses bytes in the Data sector, the instruction is

executed with the programming time tPP, when the Page Program instruction addresses

bytes in the Event sector, the instruction is executed with the fast programming time tFP.

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