
21-32
MPC561/MPC563 Reference Manual
MOTOROLA
UC3F Operation
NOTE
While there should be no harmful side effects resulting from
disabling the UC3F module while in program or erase
operation, it is not recommended that program or erase
operation be suspended in this manner.
When disabled, the power used by the UC3F is reduced to leakage levels; otherwise, the
UC3F module is enabled for accesses. For example, recovering from a stop operation
(STOP = 1), there is a recovery time of 1
s for internal biases to reach to operating levels.
21.3.11
Censored Accesses and Non-Censored Accesses
The UC3F EEPROM has a censorship mechanism which provides for several censorship
states. The censorship mechanism is used to increase restrictions in accessing Flash data.
Four bits in UC3FMCR are used to configure the UC3F censorship state. These bits are:
ACCESS—Enables a UC3F EEPROM to bypass the censorship.
FIC—Overrides CENSOR[0:1] to force information censorship.
CENSOR[0:1]—Determine the censorship state of the UC3F.
The device has two relevant modes used by the UC3F EEPROM to select the type of
censorship. The first mode, which is uncensored mode, provides no censorship. In
uncensored mode the ACCESS and CENSOR[0:1] bits are irrelevant. The second mode,
censored mode, enables the UC3F EEPROM to exercise censorship based on the state of
ACCESS, FIC, and CENSOR[0:1]. The device will enter censored mode only if one of
following events occurs:
booting from external memory
operating in peripheral mode or upon any access by an external master
operating in debug mode (BDM or Nexus)
booting from internal SRAM
In censored mode, a UC3F EEPROM may disallow accesses to the array. If censored mode
is entered by any means then the UC3F EEPROM will exercise censorship according to
.
Table 21-9. Censorship States
ACCESS
FIC
CENSOR[0:1]
Description
0
11
Information censorship, No UC3F array accesses allowed.
0
01 or 10
No censorship, UC3F array accesses allowed.
0
00
Cleared censorship, No UC3F array accesses allowed.
0
1
XX
Emulated censorship, No UC3F array accesses allowed.
1
X
XX
No censorship, UC3F array accesses allowed.