D a t a S h e e t ( P r e l i m i n a r y )
12.2 Common Flash Memory Interface
The Common Flash Interface (CFI) specification outlines device and host system software interrogation
handshake, which allows specific vendor-specified software algorithms to be used for entire families of
devices. Software support can then be device-independent, JEDEC ID-independent, and forward- and back-
ward-compatible for the specified flash device families. Flash vendors can standardize their existing
interfaces for long-term compatibility.
This device enters the CFI Query mode when the system writes the CFI Query command, 98h, to address
55h any time the device is ready to read array data. The system can read CFI information at the addresses
given in Tables 12.6–12.8). All reads outside of the CFI address range, returns non-valid data. Reads from
other sectors are allowed, writes are not. To terminate reading CFI data, the system must write the reset
command.
The system can also write the CFI query command when the device is in the autoselect mode. The device
enters the CFI query mode, and the system can read CFI data at the addresses given in Tables 12.6–12.8.
The system must write the reset command to return the device to reading array data.
The following is a C source code example of using the CFI Entry and Exit functions. 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: CFI Entry command */
*( (UINT16 *)base_addr + 0x55 ) = 0x0098;
/* write CFI entry command
/* write cfi exit command
*/
/* Example: CFI Exit command */
*( (UINT16 *)base_addr + 0x000 ) = 0x00F0;
*/
For further information, please refer to the CFI Specification (see JEDEC publications JEP137-A and
JESD68.01and CFI Publication 100). Please contact your sales office for copies of these documents.
Table 12.5 CFI Query Identification String
Addresses
(x16)
Addresses
(x8)
Data
Description
Query Unique ASCII string “QRY”
10h
11h
12h
20h
22h
24h
0051h
0052h
0059h
13h
14h
26h
28h
0002h
0000h
Primary OEM Command Set
15h
16h
2Ah
2Ch
0040h
0000h
Address for Primary Extended Table
17h
18h
2Eh
30h
0000h
0000h
Alternate OEM Command Set (00h = none exists)
Address for Alternate OEM Extended Table (00h = none exists)
19h
1Ah
32h
34h
0000h
0000h
72
S29GL-P MirrorBit® Flash Family
S29GL-P_00_A7 November 8, 2007
SPANSION [ SPANSION ]
