Chapter 33 Boot Assist Module (BAM)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
845
The flow charts in
and
provide a way to quickly check what will happen with
different configurations of the NVSCI0,1 registers as well as detailing the correct way to enter the serial
password. In the password examples, assume the 64-bit password has been programmed into the shadow
flash memory in the order {NVPWD0, NWPWD1} and has a value of 0x01234567_89ABCDEF.
Table 33-18. Censorship configuration and truth table
Boot configuration
Serial
censorship
control word
(NVSCI
n
[SC])
Censorship
control word
(NVSCI
n
[CW])
Internal
flash
memory
state
Nexus
state
Serial
password
JTAG
password
FAB pin
state
Control options
0 (flash
memory
boot)
Uncensored
0xXXXX AND
NVSCI0 ==
NVSCI1
0x55AA AND
NVSCI0 ==
NVSCI1
Enabled
Enabled
N/A
Private flash
memory password
and censored
0x55AA AND
NVSCI0 ==
NVSCI1
!0x55AA AND
NVSCI0 ==
NVSCI1
Enabled
Enabled
with
password
NVPWD
1,0
(SSCM
reads flash
memory
1
)
1
When the SSCM reads the passwords from flash memory, the NVPWD0 and NVPWD1 password order is swapped, so
you have to submit the 64-bit password as {NVPWD1, NVPWD0}.
Censored with no
password access
(lockout)
!0x55AA
!0X55AA
Enabled
Disabled
N/A
OR
NVSCI0 != NVSCI1
1 (serial
boot)
Private flash
memory password
and uncensored
0x55AA AND
NVSCI0 == NVSCI1
Enabled
Enabled
NVPWD
0,1
(BAM reads
flash
memory
Private flash
memory password
and censored
0x55AA AND
NVSCI0 ==
NVSCI1
!0x55AA AND
NVSCI0 ==
NVSCI1
Enabled
Disabled
NVPWD
1,0
(SSCM
reads flash
memory
Public password
and uncensored
!0x55AA AND
NVSCI0 !=
NVSCI1
0X55AA AND
NVSCI0 !=
NVSCI1
Enabled
Enabled
Public
(0xFEED_F
ACE_CAFE
_BEEF)
Public password
and censored
(lockout)
!0x55AA
Disabled
Disabled
Public
(0xFEED_F
ACE_CAFE
_BEEF)
OR NVSCI0 != NVSCI1
= Microcontroller permanently locked out
= Not applicable