NXP Semiconductors MPC5644A, Reference Manual, Page: 230 / 1735

Flash memory
MPC5644A Microcontroller Reference Manual, Rev. 6
230 Freescale Semiconductor
T
12.3.2.4 Secondary Low/Mid-Address Space Block Lock Register (SLMLR)
The Secondary Low/Mid-Address Space Block Lock Register (SLMLR) provides an alternative means to
protect blocks from being modified. This has the effect of creating a “tiered” locking scheme to enable
different flash users to provide different default locking on blocks. These bits, along with the LLOCK bits
in the LMLR, determine if the block is locked from program or erase. An “OR” of LMLR and SLMLR
determine the final lock status.
NOTE
A reset value of 1* in Figure 12-6 indicates that the reset value of these
registers is determined by Flash values in the shadow block. An erased
shadow block causes the reset value to be 1.
Offset 0x0008 Access: User read/write
R
HBE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
R
0 0 0 0 0 0 0 0 0 0 HBLOCK
W
Reset
0 0 0 0 0 0 0 0 0 0 1* 1* 1* 1* 1* 1*
= Unimplemented or Reserved
Figure 12-5. High-Address Space Block Lock Register (HLR)
Table 12-7. HLR field descriptions
Field Description
HBE High-Address Lock Enable
This bit is used to enable the Lock registers (HBLOCK) to be set or cleared by register writes. This
bit is a status bit only, and may not be written or cleared, and the reset value is 0. The method
to set this bit is to provide a password, and if the password matches, the HBE bit is set to reflect
the status of enabled, and is enabled until a reset operation occurs. For HBE, the password
B2B2_2222h must be written to the HLR.
0: High-Address Locks are disabled, and can not be modified.
1: High-Address Locks are enabled to be written.
HBLOCK[5:0] High-Address Space Block Lock
HBLOCK has the same characteristics as LLOCK. Please see this description for more
information. The block numbering for High-Address Space starts with HBLOCK[0] and continues
until all blocks are accounted.
HBLOCK is not writable unless HBE is high.