Flash Sector Protection - GE SBC330 3U VPX Hardware Reference Manual

Errata
May 2011
30 SBC330 3U VPX Single Board Computer
Table 5-5
Address 256 MBytes of Flash
FFFF FFFF
Boot
FF80 0000
Page 1 (248 MBytes)
(Default Page (1) pointer)
E000 0000
CS1 or CS3

5.3.7 Flash Sector protection

The SBC330 uses Spansion S29GLxxGP Flash devices, which provide advanced
methods of sector protection to ensure the integrity of code data contained in the
Flash array. Protection is defined on a per‐sector basis, where a sector is
256 KBytes (0x40000) in size. Locked sectors cannot be erased or programmed;
they may only be read.
Only the boot area of Flash is protected by a hardware jumper. Software must be
used to configure the Flash devices to protect against corruption of Flash data.
The following types of protection are provided:
• Persistent sector protection provides non‐volatile protection that remains in
place when a board is power cycled or reset. Each Flash sector may be set to
be locked (write‐protected) or unlocked (write‐enabled) by writing to
configuration registers within the Flash. The configuration of this protection
is only possible when the Flash (password) Protection Unlock Link (P10 pins
1 and 2) is fitted. If this link is not fitted, the software is unable to change the
sector protection and those sectors that are locked may not be erased or
reprogrammed under any circumstances.
• Non‐persistent protection may also be used. This protection is only present
until a power cycle or hardware reset occurs and may be modified by user
software.
NOTE
Sectors that are locked using the Persistent mode may not be unlocked using this mechanism.
NOTE
Do not rely on non-persistent protection, as it may be subsequently altered by software. If further
protection is required, use the Persistent protection method.
For further details of the protection mechanisms, refer to the Spansion
S29GL01Pxxx data sheets.
512 MBytes of Flash
Boot
Page 1 (248 MBytes)
Page 0 (256 MBytes)
(Page 0 bit set in Flash_CTRL
Register)
CS1 or CS3
Publication No. SBC330-0HH/3