Datasheet

Chapter 2 256 Kbyte Flash Module (S12FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.10
Freescale Semiconductor 95
Figure 2-9. Flash Protection Scenarios
2.3.2.6 Flash Protection Restrictions
The general guideline is that Flash protection can only be added and not removed. Table 2-16 specifies all
valid transitions between Flash protection scenarios. 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
7 6 5 4
FPHS[1:0] FPLS[1:0]
3 2 1 0
FPHS[1:0] FPLS[1:0]
FPHDIS = 1
FPLDIS = 1
FPHDIS = 1
FPLDIS = 0
FPHDIS = 0
FPLDIS = 1
FPHDIS = 0
FPLDIS = 0
Scenario
Scenario
Unprotected region
Protected region with size
Protected region Protected region with size
defined by FPLS
defined by FPHSnot defined by FPLS, FPHS
FPOPEN = 1FPOPEN = 0
PPAGE
0x0036–0x0037
0x003E–0x003F
PPAGE
0x0030–0x0035
0x0038–0x003D
PPAGE
0x0036–0x0037
0x003E–0x003F
PPAGE
0x0030–0x0035
0x0038–0x003D