S75WS256NDFBAWMB datasheet(40/216 Pages) SPANSION

40 / 216 page

S75WS256Nxx Based MCPs

S75WS-N-00_A0 February 17, 2005

Ad van c e

Inf o rmation

Any sector erase address and command following the exceeded time-out (tSEA) may or may not

be accepted. Any command other than Sector Erase or Erase Suspend during the time-out period

resets that bank to the read mode. The system can monitor DQ3 to determine if the sector erase

timer has timed out (see DQ3: Sector Erase Timeout State Indicator). The time-out begins from

the rising edge of the final WE# pulse in the command sequence.

When the Embedded Erase algorithm is complete, the bank returns to reading array data and ad-

dresses are no longer latched. Note that while the Embedded Erase operation is in progress, the

system can read data from the non-erasing banks. The system can determine the status of the

erase operation by reading DQ7 or DQ6/DQ2 in the erasing bank. See Write Operation Status for

information on these status bits.

Once the sector erase operation has begun, only the Erase Suspend command is valid. All other

commands are ignored. However, note that a hardware reset immediately terminates the erase

operation. If that occurs, the sector erase command sequence should be reinitiated once that

bank has returned to reading array data, to ensure data integrity.

Figure 8.5 illustrates the algorithm for the erase operation. See Erase/Program Timing for param-

eters and timing diagrams.

The following is a C source code example of using the sector erase function. Refer to the

Spansion Low Level Driver User’s Guide (available on www.amd.com and www.fujitsu.com)

for general information on Spansion Flash memory software development guidelines.

/* Example: Sector Erase Command */

*( (UINT16 *)base_addr + 0x555 ) = 0x00AA;

/* write unlock cycle 1

*( (UINT16 *)base_addr + 0x2AA ) = 0x0055;

/* write unlock cycle 2

*( (UINT16 *)base_addr + 0x555 ) = 0x0080;

/* write setup command

*( (UINT16 *)base_addr + 0x555 ) = 0x00AA;

/* write additional unlock cycle 1 */

*( (UINT16 *)base_addr + 0x2AA ) = 0x0055;

/* write additional unlock cycle 2 */

*( (UINT16 *)sector_address )

= 0x0030;

/* write sector erase command

Software Functions and Sample Code

Table 8.14 Sector Erase

(LLD Function = lld_SectorEraseCmd)

Cycle

Description

Operation

Byte Address

Word Address

Data

Unlock

Write

Base + AAAh

Base + 555h

00AAh

Unlock

Write

Base + 554h

Base + 2AAh

0055h

Setup Command

Write

Base + AAAh

Base + 555h

0080h

Unlock

Write

Base + AAAh

Base + 555h

00AAh

Unlock

Write

Base + 554h

Base + 2AAh

0055h

Sector Erase Command

Write

Sector Address

0030h

Unlimited additional sectors may be selected for erase; command(s) must be written within tSEA.

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