MPC563XM Reference Manual, Rev. 1
252
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Figure 11-3. PEG Valid Times
11.6.2.1.1
MCR Simultaneous Register Writes
A number of MCR bits are protected against write when another bit or set of bits is in a specific state. These
write locks are covered on a bit by bit basis in
Section 11.6.2.1, “Module Configuration Register
.” The write locks detailed in that section do not consider the effects of trying to write
two or more bits simultaneously. The effects of writing bits simultaneously which would put the Flash
module in an illegal state are detailed here.
The Flash does not allow the user to write bits simultaneously which would put the device into an illegal
state. This is implemented through a priority mechanism among the bits. The bit changing priorities are
detailed in
.
If the user attempts to write two or more MCR bits simultaneously then only the bit with the highest
priority level is written. Setting two bits with the same priority level is prevented by existing write locks
and does not put the Flash in an illegal state.
For example, setting CFLASH_MCR[STOP] and CFLASH_MCR[PGM] simultaneously results in only
CFLASH_MCR[STOP] being set. Attempting to clear CFLASH_MCR[EHV] while setting
CFLASH_MCR[PSUS] results in CFLASH_MCR[EHV] being cleared, while CFLASH_MCR[PSUS]
remains unaffected.
11.6.2.2
Low/Mid Address Space Block Locking Register (CFLASH_LMLR)
The low and mid address block locking register provides a means to protect blocks from being modified.
These bits along with bits in the secondary LMLOCK field (CFLASH_SLMLR), determine if the block is
locked from program or erase. An “OR”’ of CFLASH_LMLR and CFLASH_SLMLR determine the final
Table 11-5. MCR Bit Set/Clear Priority Levels
Priority Level
MCR Bits
1
STOP
2
ERS
3
PGM
4
EHV
5
ESUS, PSUS
CFLASH_MCR[PGM/ERS]
CFLASH_MCR[EHV]
CFLASH_MCR[DONE]
CFLASH_MCR[PEG]
PEG
Valid
PEG
Valid
PEG
Valid
Abort
Program/Erase