MC9S12G FREESCALE [Freescale Semiconductor, Inc], MC9S12G Datasheet - Page 321

• Manufacturer Part Number: MC9S12G
• Description: Ignores external trigger. Performs one conversion sequence and stops.
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 9
Security (S12XS9SECV2)
9.1
This specification describes the function of the security mechanism in the MC9S12G-Family (9SEC).
9.1.1
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 MC9S12G-Family (in secure mode) are:
9.1.2
Table 9-2
Freescale Semiconductor
Revision
Number
02.00
02.01
02.02
•
•
•
This document is valid for the S12G96 and the S12G128 device. All information related to other devices is preliminary.
Protect the content of non-volatile memories (Flash, EEPROM)
Execution of NVM commands is restricted
Disable access to internal memory via background debug module (BDM)
Flash Array Access
Introduction
gives an overview over availability of security relevant features in unsecure and secure modes.
Features
Modes of Operation
27 Aug 2004
21 Feb 2007
19 Apr 2007
Revision
No security feature is absolutely secure. However, Freescale’s strategy is to
make reading or copying the FLASH and/or EEPROM difficult for
unauthorized users.
Date
Table 9-2. Feature Availability in Unsecure and Secure Modes on S12XS
Sections
Affected
NS
✔
MC9S12G Family Reference Manual, Rev.1.01
SS
✔
Table 9-1. Revision History
Unsecure Mode
reviewed and updated for S12XD architecture
added S12XE, S12XF and S12XS architectures
corrected statement about Backdoor key access via BDM on XE, XF, XS
NX
ES
NOTE
EX
ST
Description of Changes
NS
✔
SS
✔
Secure Mode
NX
ES
EX
ST
321