MM912H634CV1AE Freescale Semiconductor, MM912H634CV1AE Datasheet - Page 231

• Manufacturer Part Number: MM912H634CV1AE
• Description: 64KS12 LIN2xLS/HS Isense
• Manufacturer: Freescale Semiconductor
• Series: -r

Specifications of MM912H634CV1AE

• Applications: Automotive
• Core Processor: HCS12
• Program Memory Type: FLASH (64 kB)
• Controller Series: HCS12
• Ram Size: 6K x 8
• Interface: LIN
• Number Of I /o: -
• Voltage - Supply: 5.5 V ~ 27 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

The security mechanism relies on non-volatile bits contained in the FLASH module. The state of these bits is passed to the
S12XMMC. Several of the MCU modules are involved in blocking certain operations which would reveal the contents of the
protected FLASH and EEPROM.
4.34
When the device is in secure mode, the following blocks are affected by security
4.34.1
There is a signal called “secreq” from the FLASH or EEPROM which indicates if the security is enabled. There is also a signal
from the xbdm, which is used in the process of unsecuring the chip. This signal is called “unsecure”. These two signals and the
resulting state of “device security” are shown in
In expanded modes, if the “mmc_secure_t2” signal is asserted, the ROMON and EEON bits are forced to zero. This operation is
independent of how the part got to expanded mode (straight out of reset or by writing the mode register).
When security is enabled and the part is brought up in special single chip mode, the secure BDM firmware is brought into the
map along with the standard BDM firmware. The secure firmware has higher priority, but does not fill the whole space. It occupies
$7F_FF80 to $7F_FFFF.
Freescale Semiconductor
Impact on MCU modules
MMC
xbdm
secreq
xdbg
unsecure
0
0
1
1
Table 333. : Security Bits - System Control
Figure 84. Chip Security Block Diagram
MM912_634 Advance Information, Rev. 4.0
Table
xmmc
333.
xgate
bdm_unsecure
mmc_secure
0
1
0
1
secreq
eeprom
flash
mmc_secure
0 (unsecured)
0 (unsecured)
0 (unsecured)
1 (secured)
security control
security status
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