S29WS-P SPANSION [SPANSION], S29WS-P Datasheet - Page 60

• Manufacturer Part Number: S29WS-P
• Description: 512/256/128 Mb (32/16/8 M x 16 bit) 1.8 V Burst Simultaneous Read/Write MirrorBit Flash Memory
• Manufacturer: SPANSION [SPANSION]

10.2
10.3
58
Customer Secured Silicon Sector
Secured Silicon Sector Entry/Exit Command Sequences
The Customer Secured Silicon Sector is typically shipped unprotected (DQ6 set to 0), allowing customers to
utilize that sector in any manner they choose. If the security feature is not required, the Customer Secured
Silicon Sector can be treated as an additional Flash memory space.
Please note the following:
The system can access the Secured Silicon Sector region by issuing the three-cycle Enter Secured Silicon
Sector command sequence. The device continues to access the Secured Silicon Sector region until the
system issues the four-cycle Exit Secured Silicon Sector command sequence.
See Command Definition Table [Secured Silicon Sector Command Table, Appendix
Table 12.1 on page 78
The Secured Silicon Sector Entry Command allows the following commands to be executed
After the system has written the Enter Secured Silicon Sector command sequence, it may read the Secured
Silicon Sector by using the addresses normally occupied by sector SA0 within the memory array. This mode
of operation continues until the system issues the Exit Secured Silicon Sector command sequence, or until
power is removed from the device.
Software Functions and Sample Code
The following are C functions and source code examples of using the Secured Silicon Sector Entry, Program,
and exit commands. Refer to the Spansion Low Level Driver User’s Guide (available soon on
www.spansion.com) for general information on Spansion Flash memory software development guidelines.
Note:
Base = Base Address.
Once the Customer Secured Silicon Sector area is protected, the Customer Indicator Bit is permanently
set to 1.
The Customer Secured Silicon Sector can be read any number of times, but can be programmed and
locked only once. The Customer Secured Silicon Sector lock must be used with caution as once locked,
there is no procedure available for unlocking the Customer Secured Silicon Sector area and none of the
bits in the Customer Secured Silicon Sector memory space can be modified in any way.
The accelerated programming (ACC) and unlock bypass functions are not available when programming the
Customer Secured Silicon Sector, but reading in Banks 1 through 15 is available.
Once the Customer Secured Silicon Sector is locked and verified, the system must write the Exit Secured
Silicon Sector Region command sequence which return the device to the memory array at sector 0.
Read customer and factory Secured Silicon areas
Program the customer Secured Silicon Sector
/* Example: Secured Silicon Sector Entry Command */
*/
*( (UINT16 *)base_addr + 0x555 ) = 0x0088;
*( (UINT16 *)base_addr + 0x555 ) = 0x00AA;
*( (UINT16 *)base_addr + 0x2AA ) = 0x0055;
Unlock Cycle 1
Unlock Cycle 2
Entry Cycle
Cycle
for address and data requirements for both command sequences.
D a t a
S h e e t
Table 10.2 Secured Silicon Sector Entry
(LLD Function = lld_SecSiSectorEntryCmd)
Operation
S29WS-P
Write
Write
Write
( A d v a n c e
/* write Secured Silicon Sector Entry Cmd
Byte Address
Base + AAAh
Base + AAAh
Base + 554h
/* write unlock cycle 1
/* write unlock cycle 2
I n f o r m a t i o n )
S29WS-P_00_A7 November 8, 2006
Word Address
Base + 2AAh
Base + 555h
Base + 555h
00AAh
0055h
0088h
Data
*/
*/