Seczonerequest(Sem) Register; Seczonerequest(Sem) Register Field Descriptions - Texas Instruments Concerto F28M35 Series Technical Reference Manual

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Flash Registers

SECZONEREQUEST Register (SEM) Register

LEGEND: R/W = Read/Write; R = Read only; -n = value after reset

Table 5-94. SECZONEREQUEST(SEM) Register Field Descriptions

Internal Memory

Figure 5-90. SECZONEREQUEST(SEM) Register

Writing the value 0xC12F59A will allow the writing of the SEM bits, else writes are ignored. Reads

will return 0.

Note: This is to prevent spurious writes of the semaphore bits.

Security Zone Semaphore for M3 Flash Wrapper registers

M3 Flash Wrapper registers can be written from code running from anywhere without any restriction

M3 Flash Wrapper registers can be written from code running from zone1 security zone

M3 Flash Wrapper registers can be written from code running from zone2 security zone

State Transitions

00,11 → 01: code running from zone 1 can perform this transition

01 → 00,11: code running from zone 1 can perform this transition

00,11 → 10 : code running from zone 2 can perform this transition

10 → 00,11 : code running from zone 2 can perform this transition

1. In case SEM = "01" writes and reads to the flash registers (including this

2. In case SEM = "10" writes and reads to the flash registers (including this

3. In case SEM = "00/11" writes and reads are not blocked.

4. Debug writes to flash registers (including this register) is blocked if SEM =

01 or SEM = 10

In addition, if sectors belonging to zone1 needs to be programmed or erased then SEM should be

01 or zone1 needs to be unlocked.

Also, if sectors belonging to zone2 needs to be programmed or erased then SEM should be 10 or

zone2 needs to be unlocked.

SPRUH22I – April 2012 – Revised November 2019

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