PXD10RM Datasheet, PDF (110/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

Address: 0x3FFC
Access: Read Always Supervisor write
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R _{HL 0 0 0 0 0 0 0 U 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0}
W^B
A
A
Reset _{0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0}
Figure 4-5. Global Configuration Register (GCR)
Table 4-4. GCR Field Descriptions
Field
HLB
Description
Hard Lock Bit.
This register can not be cleared once it is set by software. It can only be cleared by a system reset.
UAA
1 All SLB bits are write protected and can not be modified
0 All SLB bits are accessible and can be modified.
User Access Allowed.
1 The registers in the module under protection can be accessed in the User mode without any
additional restrictions.
0 The registers in the module under protection can only be written in supervisor mode. All write
accesses in non-supervisor mode are not executed and a transfer error is issued. This access
restriction is in addition to any access restrictions imposed by the protected IP module.
NOTE
The GCR.UAA bit has no effect on the allowed access modes for the
registers in the Register Protection module.
4.1.4 Functional Description
4.1.4.1 General
This module provides a generic register (address) write-protection mechanism. The protection size can be:
• 32-bit (address == multiples of 4)
• 16-bit (address == multiples of 2)
• 8-bit (address == multiples of 1)
• unprotected (address == multiples of 1)
Which addresses are protected and the protection size depend on the SoC and/or module. Therefore this
section can just give examples for various protection configurations.
For all addresses that are protected there are SLBRn.SLBm bits that specify whether the address is locked.
When an address is locked it can only be read but not written in any mode (supervisor/normal). If an
address is unprotected the corresponding SLBRn.SLBm bit is always 0b0 no matter what software is
writing to.
PXD10 Microcontroller Reference Manual, Rev. 1
4-6
Freescale Semiconductor
Preliminary—Subject to Change Without Notice