Specifications

February 2015 IS29GL_128S_01GS_00_Rev.A GL-S MirrorBit
®
Family 35
Data Sheet
5.3.6 ASO Entry and Exit
5.3.6.1 ID-CFI ASO
The system can access the ID-CFI ASO by issuing the ID-CFI Entry command sequence during Read Mode.
This entry command uses the Sector Address (SA) in the command to determine which sector will be overlaid
and which sector's protection state is reported in word location 2h. See the detail description Table 6.2
on page 60.
The ID-CFI ASO allows the following activities:
 Read ID-CFI ASO, using the same SA as used in the entry command.
 Read Sector Protection State at Sector Address (SA) + 2h. Location 2h provides volatile information on the
current state of sector protection for the sector addressed. Bit 0 of the word at location 2h shows the logical
NAND of the PPB and DYB bits related to the addressed sector such that if the sector is protected by either
the PPB=0 or the DYB=0 bit for that sector the state shown is protected. (1= Sector protected, 0= Sector
unprotected). This protection state is shown only for the SA selected when entering ID-CFI ASO. Reading
other SA provides undefined data. To read a different SA protection state ASO exit command must be used
and then enter ID-CFI ASO again with the new SA.
 ASO Exit.
The following is a C source code example of using the CFI Entry and Exit functions. Refer to the ISSI Low
Level Driver User's Guide (available on www.ISSI.com) for general information on ISSI flash memory
software development guidelines.
/* Example: CFI Entry command */
*( (UINT16 *)base_addr + 0x55 ) = 0x0098; /* write CFI entry command */
/* Example: CFI Exit command */
*( (UINT16 *)base_addr + 0x000 ) = 0x00F0; /* write cfi exit command */
5.3.6.2 Status Register ASO
The Status Register ASO contains a single word of registered volatile status for Embedded Algorithms. When
the Status Register read command is issued, the current status is captured (by the rising edge of WE#) into
the register and the ASO is entered. The Status Register content appears on all word locations. The first read
access exits the Status Register ASO (with the rising edge of CE# or OE#) and returns to the address space
map in use when the Status Register read command was issued. Write commands will not exit the Status
Register ASO state.
5.3.6.3 Secure Silicon Region ASO
The system can access the Secure Silicon Region by issuing the Secure Silicon Region Entry command
sequence during Read Mode. This entry command uses the Sector Address (SA) in the command to
determine which sector will be overlaid.
The Secure Silicon Region ASO allows the following activities:
 Read Secure Silicon Regions.
 Programming the customer Secure Silicon Region is allowed using the Word or Write Buffer Programming
commands.
 ASO Exit using legacy Secure Silicon Exit command for backward software compatibility.
 ASO Exit using the common exit command for all ASO - alternative for a consistent exit method.