S75WS256NDFBAWMB datasheet(36/216 Pages) SPANSION

36 / 216 page

S75WS256Nxx Based MCPs

S75WS-N-00_A0 February 17, 2005

Ad van c e

Inf o rmation

Note: Base = Base Address.

The following is a C source code example of using the single word program 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: Program Command

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

/* write unlock cycle 1

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

/* write unlock cycle 2

*( (UINT16 *)base_addr + 0x555 ) = 0x00A0;

/* write program setup command

*( (UINT16 *)pa )

= data;

/* write data to be programmed

/* Poll for program completion */

8.5.2

Write Buffer Programming

Write Buffer Programming allows the system to write a maximum of 32 words in one program-

ming operation. This results in a faster effective word programming time than the standard word

programming algorithms. The Write Buffer Programming command sequence is initiated by first

writing two unlock cycles. This is followed by a third write cycle containing the Write Buffer Load

command written at the Sector Address in which programming occurs. At this point, the system

writes the number of word locations minus 1 that are loaded into the page buffer at the Sector

Address in which programming occurs. This tells the device how many write buffer addresses are

loaded with data and therefore when to expect the Program Buffer to Flash confirm command.

The number of locations to program cannot exceed the size of the write buffer or the operation

aborts. (Number loaded = the number of locations to program minus 1. For example, if the sys-

tem programs 6 address locations, then 05h should be written to the device.)

The system then writes the starting address/data combination. This starting address is the first

address/data pair to be programmed, and selects the write-buffer-page address. All subsequent

address/data pairs must fall within the elected-write-buffer-page.

The write-buffer-page is selected by using the addresses AMAX - A5.

The write-buffer-page addresses must be the same for all address/data pairs loaded into the write

buffer. (This means Write Buffer Programming cannot be performed across multiple write-buffer-

pages. This also means that Write Buffer Programming cannot be performed across multiple sec-

tors. If the system attempts to load programming data outside of the selected write-buffer-page,

the operation ABORTs.)

After writing the Starting Address/Data pair, the system then writes the remaining address/data

pairs into the write buffer.

Note that if a Write Buffer address location is loaded multiple times, the address/data pair counter

is decremented for every data load operation. Also, the last data loaded at a location before the

Program Buffer to Flash confirm command is programmed into the device. It is the software's re-

sponsibility to comprehend ramifications of loading a write-buffer location more than once. The

Software Functions and Sample Code

Table 8.12 Single Word Program

(LLD Function = lld_ProgramCmd)

Cycle

Operation

Byte Address

Word Address

Data

Unlock Cycle 1

Write

Base + AAAh

Base + 555h

00AAh

Unlock Cycle 2

Write

Base + 554h

Base + 2AAh

0055h

Program Setup

Write

Base + AAAh

Base + 555h

00A0h

Program

Write

Word Address

Data Word

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