ADLINK CoreExpress-ECO2 - Manual (Page 29)

4.23 Write-protect SECURE-Area
This single command enables the protection of total SECURE-Area against write accesses. Since the
SECURE-Area is located at the bootloader region, the bootloader will also locked. No further
bootloader update is possible when the SECURE-Area is locked. To prevent unintentional protect of
the SECURE-Area two Magic Bytes must be send with this command (see Table 4.23.2).
Caution: If this security setting has been applied, the SECURE-Area of that device will not be
rewritten by anyone (protected by hardware-fuse).
START SMC_addr ACK command ACK length ACK Magic_1 ACK Magic_2 ACK STOP
Table 4.23.1 SMC receiver format of the Write-protect SECURE-Area Command Code
ITEM DESCRIPTION
START SM-bus start condition
SMC_addr 01010000b = 0x50 (8-bit) (Write access to SMC)
ACK SM-bus acknowledge condition generated by receiver
command 0x44 = “Write-protect SECURE-Area” Command code
length 0x02 = Length of this Command
Magic_1 0xAE = Magic Byte 1
Magic_2 0xCE = Magic Byte 2
STOP SM-bus stop condition
Table 4.23.2 Explanation of Table 4.23.1