User Manual
299
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
Memory Control Unit
If the BootROM, the Customer BSL, the NVM Linear and the NVM Non-Linear protection modes are enabled:
• Data reading instructions executed from the Non-Linear NVM can target the RAM
• Data reading instructions executed from the RAM can target itself
• Data reading instructions executed from the BootROM can target itself
• Data reading instructions executed from the Customer BSL NVM region can target itself, Non-Linear NVM
or RAM
• Data reading instructions executed from the NVM Linear region can target itself, Non-Linear NVM or RAM
11.6.2.2.4
NVM Protection Mode Control
The read and write protection on the different regions are controlled via the register NVM_PROT_STS.
The value of this register can be changed in 2 different ways.
Memory region protection password
The first method is based on a region specific protection password. After the complete code has been
programmed into the Customer BSL and Linear NVM regions, the protection scheme can be enabled by calling
the BootROM password routine by means of the dedicated TLE984xQX BSL mode. The BootROM password
routine programs a user provided password into the reserved space register according to the information
stored into the 2 most significant bits of the password. The format of the password is shown in the
Figure 52 NVM Region Password Format
To allow external access to the device or to reprogram a new password
When removing the password via the BootROM password routine, in case the provided password does not
match the valid password currently stored
There is a password for each region.
Memory region protection register access
The hardware memory protection mechanism is controlled by the values of the NVM_ PROT_STS register bits.
When user set a protection via password, the BootROM startup sequence enables proper protection modes by
writing the related bit of the NVM_PROT_STS register.
31
30
29 …………………………………………………………………………………..0
Bit 31:
0 = read protection disabled
1 = read protection enabled
Bit 30:
0 = write protection disabled
1 = write protection enabled
Bit( 29 to 0)
Password value