D a t a S h e e t ( P r e l i m i n a r y )
7.7.4
Chip Erase Command Sequence
Chip erase is a six-bus cycle operation as indicated by Table 12.1 on page 68. These commands invoke the
Embedded Erase algorithm, which does not require the system to preprogram prior to erase. The Embedded
Erase algorithm automatically preprograms and verifies the entire memory to an all zero data pattern prior to
electrical erase. After a successful chip erase, all locations of the chip contain FFFFh. The system is not
required to provide any controls or timings during these operations. The Command Definitions on page 67
shows the address and data requirements for the chip erase command sequence.
When the Embedded Erase algorithm is complete, that sector returns to the read mode and addresses are no
longer latched. The system can determine the status of the erase operation by using DQ7 or DQ6/DQ2. Refer
to “Write Operation Status” for information on these status bits.
The Unlock Bypass feature allows the host system to send program commands to the Flash device without
first writing unlock cycles within the command sequence. See Section 7.7.8 for details on the Unlock Bypass
function.
Any commands written during the chip erase operation are ignored. However, note that a hardware reset
immediately terminates the erase operation. If that occurs, the chip erase command sequence should be
reinitiated once that sector has returned to reading array data, to ensure the entire array is properly erased.
Software Functions and Sample Code
Table 7.9 Chip Erase
(LLD Function = lld_ChipEraseCmd)
Cycle
Description
Unlock
Operation
Write
Byte Address
Base + AAAh
Base + 555h
Base + AAAh
Base + AAAh
Base + 555h
Base + AAAh
Word Address
Base + 555h
Base + 2AAh
Base + 555h
Base + 555h
Base + 2AAh
Base + 555h
Data
00AAh
0055h
0080h
00AAh
0055h
0010h
1
2
3
4
5
6
Unlock
Write
Setup Command
Unlock
Write
Write
Unlock
Write
Chip Erase Command
Write
The following is a C source code example of using the chip erase function. Refer to the Spansion Low Level
Driver User’s Guide (available on www.spansion.com) for general information on Spansion Flash memory
software development guidelines.
/* Example: Chip Erase Command */
/* Note: Cannot be suspended
*/
*( (UINT16 *)base_addr + 0x555 ) = 0x00AA;
*( (UINT16 *)base_addr + 0x2AA ) = 0x0055;
*( (UINT16 *)base_addr + 0x555 ) = 0x0080;
*( (UINT16 *)base_addr + 0x555 ) = 0x00AA;
*( (UINT16 *)base_addr + 0x2AA ) = 0x0055;
*( (UINT16 *)base_addr + 0x000 ) = 0x0010;
/* write unlock cycle 1
/* write unlock cycle 2
/* write setup command
*/
*/
*/
/* write additional unlock cycle 1 */
/* write additional unlock cycle 2 */
/* write chip erase command
*/
32
S29GL-P MirrorBit® Flash Family
S29GL-P_00_A7 November 8, 2007
SPANSION [ SPANSION ]
