MC9S12C128V1 Datasheet, PDF (480/690 Pages) Freescale Semiconductor, Inc – MC9S12C Family MC9S12GC Family Reference Manual

Chapter 17 16 Kbyte Flash Module (S12FTS16KV1)
Figure 17-9 illustrates all possible protection scenarios. Although the protection scheme is loaded from the
Flash array after reset, it is allowed to change in normal modes. This protection scheme can be used by
applications requiring re-programming in single chip mode while providing as much protection as possible
if no re-programming is required.
Scenario
FPHDIS = 1
3
FPHDIS = 0
2
0xFFFF
Scenario
1
0
0xFFFF
Protected Flash
Figure 17-9. Flash Protection Scenarios
17.3.2.5.1 Flash Protection Restrictions
The general guideline is that protection can only be added, not removed. All valid transitions between
Flash protection scenarios are specified in Table 17-11. Any attempt to write an invalid scenario to the
FPROT register will be ignored and the FPROT register will remain unchanged. The contents of the
FPROT register reflect the active protection scenario.
Table 17-11. Flash Protection Scenario Transitions
From
Protection
Scenario
To Protection Scenario⁽¹⁾
0
1
2
3
0
X
X
1
X
2
X
X
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MC9S12C-Family / MC9S12GC-Family
Freescale Semiconductor
Rev 01.24