SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
For each of the two security zones, a dedicated OTP block exists on CPU1 that holds the configuration related to zone’s security. The following are user programmable configurations:
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Since OTP cannot be erased, the following configurations are placed in zone select blocks of each zone’s OTP Flash of both the banks:
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The location of the valid zone select block in OTP is decided based on the value of three 14-bit link pointers (Zx-LINKPOINTERx) programmed in the OTP of each zone. All OTP locations except link pointers and Z1OTP_JLM_ENABLE locations are protected with ECC. Since the link pointer locations are not protected with ECC, three link pointers are provided that need to be programmed with the same value. The final value of the link pointer is resolved in hardware, when a dummy read is done to all the link pointers, by comparing all the three values (bit-wise voting logic). Since in OTP, a ‘1’ can be flipped by the user to ‘0’ but ‘0’ can not be flipped to ‘1’ (no erase operation for OTP), the most significant bit position in the resolved link pointer which is ‘0’, defines the valid base address for the zone select block. While generating the final link pointer value, if the bit pattern is not one of those listed in Figure 6-1, the final link pointer value becomes All_1 (0xFFFF_FFFF), which selects the Zone-Select-Block1 (also known as the default zone select block).