XC2200 Derivatives
System Units (Vol. 1 of 2)
Memory Organization
User’s Manual
3-38
V2.1, 2008-08
MemoryX2K, V1.3
3.9.6
Protection Handling Details
“Protection Overview” on Page 3-36
the flash memory can be
in different protection states. The protection handling can be separated into different
layers that interact which each other (see
).
•
The lowest layer consists of the physical content of the security pages SecP0 and
SecP1. This information is used to initialize the protection system during startup.
•
The next layer consists of registers that report the state of the physical layer
(IMB_PROCONx) and the protection state (IMB_FSR). The protection state can be
temporarily changed with command sequences which is reflected in the IMB_FSR.
•
The highest layer is represented by 4 fields of the IMB_IMBCTR register. These fields
define the protection rights of the customer software (are read or write accesses
currently allowed or not).
The IMB Core controls the protection state of all connected flash modules centrally. In
this position it can supervise all accesses that are issued by the CPU.
Figure 3-7
Protection Layers
Physical Layer
Middle Layer
IMB_FSR
RPRO
WPRODIS
PROINER
PROIN
RPRODIS
IMB_PROCONx
PROCONs
Lock Code
RPRO
Passwords
PROCONs
IMB_FSR
Security Page 0
Security Page 1
Upper Layer
RPA
WPA
IMB_CTRH
IMB_CTRL
DDF
DCF
copied
influences
Erase/
Program
Sec. Page
Disable/ Re-
Enable
Protection
influences indirectly
Write to
DDF/DCF
Boot Mode
flash_protection.vsd