mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 1231

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 30
Security (S12X9SECV2)
30.1
This specification describes the function of the security mechanism in the S12X chip family
(S12X9SECV2).
30.1.1
The user must be reminded that part of the security must lie with the application code. An extreme example
would be application code that dumps the contents of the internal memory. This would defeat the purpose
of security. At the same time, the user may also wish to put a backdoor in the application program. An
example of this is the user downloads a security key through the SCI, which allows access to a
programming routine that updates parameters stored in another section of the Flash memory.
The security features of the S12X chip family (in secure mode) are:
Table 30-1
Freescale Semiconductor
•
•
•
•
•
Protect the contents of non-volatile memories (Flash, EEPROM)
Execution of NVM commands is restricted
Disable access to internal memory via background debug module (BDM)
Disable access to internal Flash/EEPROM in expanded modes
Disable debugging features for CPU and XGATE
Introduction
gives an overview over availability of security relevant features in unsecure and secure modes.
Features
MC9S12XDP512 Data Sheet, Rev. 2.17
1231