Datasheet

Chapter 2 128 Kbyte Flash Module (FTS128K1V1)
MC9S12E128 Data Sheet, Rev. 1.07
96 Freescale Semiconductor
Figure 2-9. Flash Protection Scenarios
2.3.2.5.1 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 2-12. 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 2-12. Flash Protection Scenario Transitions
From
Protection
Scenario
To Protection Scenario
1
01234567
0 XXXX
1XX
2XX
3X
4XX
5 XXXX
7 6 5 4
FPOPEN = 1
3 2 1 0
FPHS[1:0]
FPLS[1:0]
FPOPEN = 0
FPHDIS = 1
FPLDIS = 1
FPHDIS = 1
FPLDIS = 0
FPHDIS = 0
FPLDIS = 1
FPHDIS = 0
FPLDIS = 0
Scenario
Scenario
Protected Flash
FPHS[1:0]
FPLS[1:0]
0xFFFF
0xFFFF