/*!
\file readme.txt
\brief description of system clock switch example with TZEN=1
\version 2021-10-30, V1.0.0, firmware for GD32W51x
*/
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This example is based on the GD32W515P-EVAL-V1.0 board, the project consists of
two sub-projects, secure project and nonsecure project. It shows how to switch from
secure application to non-secure application, and call secure functions in nonsecure
application. The switch_system_clock_to_120m_hxtal function and switch_system_clock_to_180m_irc16m
fucntion is defined in non-secure callable area in secure application, and is called
by nonsecure application.
The system always starts from the secure application, and the secure application is
responsible for starting the nonsecure application.Therefore, in the compilation process,
first compile the secure project, and then compile the nonsecure project.
Before downloading the program, the option byte needs to be configured as follows:
1.enable trustzone
TZEN = 1
2.configure secure mark pages
FMC_SECMCFG0 = 0x003F0000
startpage :0x00 endpage:0x3F means that the first 64 pages of flash are configured
as secure
In secure application,the program execution follows the following steps:
1.configre SAU/IDAU, FPU and secure/nosecure interrupts allocations in partition_gd32w51x.h file
the key configuration is as follows:
Enable SAU
SAU Region 0 start address: 0x0C03E000 end address: 0xC003FFFF Attributes: S/NSC
SAU Region 1 start address: 0x08040000 end address: 0x08200000 Attributes: NS
SAU Region 2 start address: 0x20010000 end address: 0x2001FFFF Attributes: NS
SAU Region 3 start address: 0x40000000 end address: 0x4FFFFFFF Attributes: NS
EXTI2 IRQn configer as Non-Secure State
2.configure TZBMPC
TZBMPC1 vector register y(y=0 to 7):0x00000000 means that SRAM1(64KB) are configured as nonsecure
3.Setup and jump to non-secure application
In non-secure application, when the KEY_TAMPER_WAKEUP is pressed, the system performs a clock switch by
non-secure function defined in secure project, and then updata the systick config, the LED1
blinking frequency will be changed.