MOTOROLA
Chapter 21. CDR3 Flash (UC3F) EEPROM
21-7
Programming Model
1LOCK 1
Lock control. The default reset state of LOCK is 1. This enables writing of all fields in the Flash
registers.
Once the LOCK bit has been asserted (LOCK = 0) in normal operating mode, the write-lock can
only be disabled again by a reset. When the device is in background debug mode and CSC = 0,
the LOCK bit may be written from a 0 to a 1.
When the LOCK control bit is cleared to 0, the write-locked register bits: FIC, SUPV, SBSUPV[0:1],
DATA, SBDATA, PROTECT, SBPROTECT, and SBEN[0:1] are locked. Writes to these bits while
LOCK = 0 will have no effect.
LOCK can be written to 0 once after reset when UC3FCTL[CSC] = 0 to allow protection of the
write-locked register bits after initialization.
WARNING:
If the lock protection mechanism is enabled (LOCK = 0) before PROTECT and
SBPROTECT are cleared, the device must use background debug mode to
program or erase the UC3F EEPROM.
2—
Reserved
3
FIC
Force information censorship. The default reset state of FIC is normal censorship operation
(FIC = 0). The FIC bit is write protected by the LOCK bit and the UC3FCTL[CSC] bit. Writes will
have no effect if LOCK = 0 or CSC = 1. Once FIC is set (FIC = 1), it cannot be cleared except by a
reset. The FIC bit can be read whenever the registers are enabled.
The FIC bit is a censorship emulation mode used to aid in the development of custom techniques
for controlling the ACCESS bit without setting CENSOR[0:1] to the information censorship state.
Using FIC to force information censorship allows testing of the hardware and software for setting
ACCESS without setting CENSOR[0:1] = 11 and risk permanently setting the device into an
unusable information censorship state.
0 = normal uc3f censorship operation
1 = forces the uc3f into information censorship mode
4
SIE
Shadow information enable. The default reset state of SIE is 0. The SIE bit is write protected in
program operation (SES = 1 and PE = 0). The SIE bit can be read whenever the registers are
enabled.
When SIE = 1, normal array accesses are disabled, and the two shadow information rows are
enabled. Array accesses are directed to the shadow row while SIE = 1. When an array location is
read in this mode, only the lower 6 address bits are used to select which 64 bytes of the 512-byte
shadow row are read. The upper address bits are not used for shadow row decoding. The read
page buffer address monitor is reset whenever SIE is modified making the next UC3F array access
an off page access.
0 = normal array access
1 = disables normal array access and selects the shadow information rows
5
ACCESS
Enable uncensored access. A censored access to the UC3F EEPROM is any access where the
device is in the censored mode.
The default reset state is ACCESS is a 0 so that FIC and CENSOR[0:1] control the state of
censorship to the UC3F EEPROM array. All accesses to the UC3F EEPROM array is allowed if
ACCESS = 1.
ACCESS can be read whenever the registers are enabled. ACCESS provides a method to bypass
the UC3F EEPROM module censorship.
0 Censored - UC3F array access allowed only if the censorship state is no censorship
1 Allows all UC3F array access
Table 21-3. UC3FMCR Bit Descriptions (continued)
Bits
Name
Description