MPC5604B/C Microcontroller Reference Manual, Rev. 8
68 Freescale Semiconductor
CAUTION
If the contents of the shadow flash memory are erased and the NVSCC0,1
registers are not re-programmed to a valid value, the microcontroller will be
permanently censored with no way for you to regain access. A
microcontroller in this state cannot be debugged or re-flashed.
5.1.3.3 Censorship configuration
The steps to configuring censorship are:
1. Define a valid 64-bit password that conforms to the password rules.
2. Using the table and flow charts below, decide what level of censorship you require and configure
the NVSCC0,1 values.
3. Re-program the shadow flash memory and NVPWD0,1 and NVSCC0,1 registers with your new
values. A POR is required before these will take effect.
CAUTION
If
(NVSCC0 and NVSCC1 do not match)
or
(Either NVSCC0 or NVSCC1 is not set to 0x55AA)
then the microcontroller will be permanently censored with no way to get
back in.
Table 5-4 shows all the possible modes of censorship. The red shaded areas are to be avoided as these show
the configuration for a device that is permanently locked out. If you wish to enable censorship with a
private password there is only one valid configuration — to modify the CW field in both NVSCC0,1
registers so they match but do not equal 0x55AA. This will allow you to enter the private password in both
serial and flash boot modes.
To Next Page
Loading...
