MC9S08DZ128 Datasheet, PDF (80/458 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 4 Memory
4.6.11.4 FLASH and EEPROM Protection Register (FPROT and NVPROT)
The FPROT register defines which FLASH and EEPROM sectors are protected against program and erase
operations.
During the reset sequence, the FPROT register is loaded from the nonvolatile location NVPROT. To
change the protection that will be loaded during the reset sequence, the sector containing NVPROT must
be unprotected and erased, then NVPROT can be reprogrammed.
FPROT bits are readable at any time and writable as long as the size of the protected region is being
increased. Any write to FPROT that attempts to decrease the size of the protected memory will be ignored.
Trying to alter data in any protected area will result in a protection violation error and the FPVIOL flag
will be set in the FSTAT register. Mass erase is not possible if any one of the sectors is protected.
7
6
5
4
3
2
1
0
R
EPS
W
FPS
FPOP
Reset
F
F
F
F
F
F
F
F
Field
7:6
EPS
5:1
FPS
0
FPOP
Figure 4-17. FLASH and EEPROM Protection Register (FPROT)
Table 4-18. FPROT Register Field Descriptions
Description
EEPROM Protect Select Bits — This 2-bit field determines the protected EEPROM locations that cannot be
erased or programmed. See Table 4-19.
FLASH Protect Select Bits — With FPOP set, this 5-bit field determines the protected FLASH locations that
cannot be erased or programmed. SeeTable 4-20.
FLASH Protection Open
0 Flash is fully protected.
1 Flash protected address range determined by FPS bits.
EPS
0x3
0x2
0x1
0x0
Table 4-19. EEPROM Block Protection
Protected Address Range
No protection
3FF0 - 3FFF
3FE0 - 3FFF
3FC0–3FFF
Protected Size
0 bytes
32 bytes
64 bytes
128 bytes
MC9S08DZ128 Series Data Sheet, Rev. 1
80
Freescale Semiconductor