S912XET256J2VAGR Freescale Semiconductor, S912XET256J2VAGR Datasheet - Page 347

• Manufacturer Part Number: S912XET256J2VAGR
• Description: 16-bit Microcontrollers - MCU Watchdog OSC/Timer -40 C to + 105 C HCS12X MCU SPI
• Manufacturer: Freescale Semiconductor

Specifications of S912XET256J2VAGR

• Core: HCS12X
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 50 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 16 KB
• On-chip Adc: Yes
• Package / Case: LQFP
• Mounting Style: SMD/SMT
• A/d Bit Size: 12 bit
• A/d Channels Available: 24
• Interface Type: CAN, SCI, SPI
• Maximum Operating Temperature: + 105 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 119
• Number Of Timers: 25
• Program Memory Type: Flash
• Supply Voltage - Max: 1.98 V, 2.9 V, 5.5 V
• Supply Voltage - Min: 1.72 V, 2.7 V, 3.13 V

Chapter 9
Security (S12XE9SECV2)
9.1
This specification describes the function of the security mechanism in the S12XE chip 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 S12XE chip family (in secure mode) are:
Freescale Semiconductor
Revision
Number
V02.00
V02.01
V02.02
•
•
•
•
•
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)
Disable access to internal Flash/EEPROM in expanded modes
Disable debugging features for the CPU and XGATE
Introduction
Revision Date
Features
27 Aug 2004
21 Feb 2007
19 Apr 2007
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.
Sections
Affected
MC9S12XE-Family Reference Manual Rev. 1.25
Table 9-1. Revision History
- Reviewed and updated for S12XD architecture
- Added S12XE, S12XF and S12XS architectures
- Corrected statement about Backdoor key access via BDM on XE, XF, XS
NOTE
Description of Changes
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