Freescale Semiconductor MPC5604B - 4. Developing a general purpose UART Driver

MPC5604B/C Microcontroller Reference Manual, Rev. 8
76 Freescale Semiconductor
5.2.1.3.2 Censorship enabled (private password)
1. Since the flash is secured, the SSCM is required to read the private password.
2. The BAM code writes the serial password to the SSCM_PWCMPH and SSCM_PWCMPL
registers.
3. The BAM code then continues with the serial download (start address, data size and data) until all
the data has been copied to the SRAM.
4. In the meantime the SSCM has compared the private password in flash with the serial download
password the BAM code wrote into SSCM_PWCMPH and SSCM_PWCMPL.
5. If the SSCM obtains a match in the passwords, the censorship is temporarily disabled (until the
next reset).
6. The SSCM updates the status of the security (SEC) bit to reflect whether the passwords matched
(SEC = 0) or not (SEC = 1)
7. Finally, the BAM code reads SEC. If SEC = 0, execution is transferred to the code in the SRAM.
If SEC = 1, the BAM code forces the microcontroller into static mode.
Figure 5-8 shows this in more detail.