AN4253 datasheet(8/44 Pages) STMICROELECTRONICS

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After reset init

AN4253

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DocID024255 Rev 2

After reset init

Figure 2. Flow of the "After reset init" phase

2.1

Core Register Init (LSM)

In Lock Step (LSM) Mode it is mandatory to initialize the core specific purpose register to

avoid redundant checker faults under specific circumstances. The reason for the faults

comes from the fact that not all core specific purpose registers are initialized after reset and

their difference can cause RCCU fault later on.

It is not necessary to initialize the core SPRs registers when the device is operating in

decoupled mode.

2.1.1

Code sequence

Write to selected Core Specific Purpose Registers (SPRs) any

value

2.2

Memory Management Unit (MMU)

Default reset MMU configuration in each core enables instruction fetch from 4 KB memory

block area starting from a reset vector address. 4 KB code area may or may not be sufficient

for the startup code, but a main issue of the default MMU configuration is missing access

setup for RAM memory and for peripheral modules. They must be explicitly added to the

MMU table before any access is executed to them by the startup code.

AN4253 Datasheet(PDF) 8 Page - STMicroelectronics