MC9S12T64 Datasheet, PDF (208/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Flash EEPROM 64K
FSEC — Flash
Security Register
This FSEC register holds all bits associated with the device security.
This register is unbanked.
Address Offset: $0101
Bit 7
Read: KEYEN
Write:
Reset: F
6
5
4
NV6
NV5
NV4
F
F
F
= Reserved or unimplemented
3
NV3
F
2
1
Bit 0
NV2
SEC1
SEC0
F
F
F
Read: Anytime
Write: Never
NOTE: Access to this register during Flash Super User mode (FSUM=1) will
cause the ACCERR bit set.
The FSEC register is loaded from the Flash Protection/Options field byte
at $FF0F during the reset sequence, indicated by “F” in the reset row of
the register description.
KEYEN — Enable backdoor key to security
1 = backdoor to Flash is enabled
0 = backdoor to Flash is disabled
NV[6:2] — Non Volatile Flag Bits
These 5 bits are available to the user as non-volatile flags.
SEC[1:0] — Memory Security Bits
The SEC[1:0] bits define the security state of the device as shown in
Table 40. If the Flash is unsecured using the Backdoor Key Access,
the SEC bits are forced to 10.
Table 40 Security States
SEC[1:0]
00
01
10
11
Description
secured
secured
unsecured
secured
MC9S12T64Revision 1.1.1
Flash EEPROM 64K
For More Information On This Product,
Go to: www.freescale.com