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AT25320A Datasheet(PDF) 8 Page - ATMEL Corporation |
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AT25320A Datasheet(HTML) 8 Page - ATMEL Corporation |
8 / 19 page 8 AT25080A/160A/320A/640A 3401C–SEEPR–8/04 WRITE STATUS REGISTER (WRSR): The WRSR instruction allows the user to select one of four levels of protection. The AT25080A/160A/320A/640A is divided into four array segments. One-quarter, one-half, or all of the memory segments can be protected. Any of the data within any selected segment will therefore be read-only. The block write protection levels and corre- sponding status register control bits are shown in Table 8. The three bits BP0, BP1, and WPEN are nonvolatile cells that have the same properties and functions as the regular memory cells (e.g., WREN, tWC, RDSR). The WRSR instruction also allows the user to enable or disable the write protect (WP) pin through the use of the Write Protect Enable (WPEN) bit. Hardware write protection is enabled when the WP pin is low and the WPEN bit is “1”. Hardware write protection is disabled when either the WP pin is high or the WPEN bit is “0”. When the device is hardware write-protected, writes to the status register, including the block protect bits and the WPEN bit, and the block- protected sections in the memory array are disabled. Writes are only allowed to sections of the memory that are not block-protected. NOTE: When the WPEN bit is hardware write-protected, it cannot be changed back to “0” as long as the WP pin is held low. Table 8. Block Write Protect Bits Level Status Register Bits Array Addresses Protected BP1 BP0 AT25080A AT25160A AT25320A AT25640A 0 0 0 None None None None 1(1/4) 01 0300 −03FF 0600 −07FF 0C00 −0FFF 1800 −1FFF 2(1/2) 10 0200 −03FF 0400 −07FF 0800 −0FFF 1000 −1FFF 3(All) 11 0000 −03FF 0000 −07FF 0000 −0FFF 0000 −1FFF Table 9. WPEN Operation WPEN WP WEN Protected Blocks Unprotected Blocks Status Register 0 X 0 Protected Protected Protected 0 X 1 Protected Writable Writable 1 Low 0 Protected Protected Protected 1 Low 1 Protected Writable Protected X High 0 Protected Protected Protected X High 1 Protected Writable Writable |
Similar Part No. - AT25320A_14 |
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Similar Description - AT25320A_14 |
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