MC9S12G Datasheet, PDF (322/1160 Pages) Freescale Semiconductor, Inc – Ignores external trigger. Performs one conversion sequence and stops.

Security (S12XS9SECV2)
Table 9-2. Feature Availability in Unsecure and Secure Modes on S12XS
Unsecure Mode
Secure Mode
NS SS NX ES EX ST NS SS NX ES EX ST
EEPROM Array Access ✔ ✔
NVM Commands
✔¹ ✔
BDM
✔✔
✔✔
✔¹ ✔¹
— ✔²
DBG Module Trace
✔✔
——
1 _{Restricted NVM command set only. Please refer to the NVM wrapper block guides for detailed information.}
2 _{BDM hardware commands restricted to peripheral registers only.}
9.1.3 Securing the Microcontroller
Once the user has programmed the Flash and EEPROM, the chip can be secured by programming the
security bits located in the options/security byte in the Flash memory array. These non-volatile bits will
keep the device secured through reset and power-down.
The options/security byte is located at address 0xFF0F (= global address 0x7F_FF0F) in the Flash memory
array. This byte can be erased and programmed like any other Flash location. Two bits of this byte are used
for security (SEC[1:0]). On devices which have a memory page window, the Flash options/security byte
is also available at address 0xBF0F by selecting page 0x3F with the PPAGE register. The contents of this
byte are copied into the Flash security register (FSEC) during a reset sequence.
0xFF0F
7
KEYEN1
6
KEYEN0
5
NV5
4
NV4
3
NV3
2
NV2
Figure 9-1. Flash Options/Security Byte
1
SEC1
0
SEC0
The meaning of the bits KEYEN[1:0] is shown in Table 9-3. Please refer to Section 9.1.5.1, “Unsecuring
the MCU Using the Backdoor Key Access” for more information.
Table 9-3. Backdoor Key Access Enable Bits
KEYEN[1:0]
00
01
10
11
Backdoor Key
Access Enabled
0 (disabled)
0 (disabled)
1 (enabled)
0 (disabled)
The meaning of the security bits SEC[1:0] is shown in Table 9-4. For security reasons, the state of device
security is controlled by two bits. To put the device in unsecured mode, these bits must be programmed to
SEC[1:0] = ‘10’. All other combinations put the device in a secured mode. The recommended value to put
the device in secured state is the inverse of the unsecured state, i.e. SEC[1:0] = ‘01’.
MC9S12G Family Reference Manual, Rev.1.01
322
Freescale Semiconductor
This document is valid for the S12G96 and the S12G128 device. All information related to other devices is preliminary.