1.什么是bootloader
Bootloader（引导加载程序） 是存储在设备非易失性存储器（如 ROM、Flash）中的一段特殊程序，负责在设备上电后初始化硬件、加载操作系统（OS）或用户应用程序，并最终将控制权移交给它们。它是设备启动过程中第一个运行的软件，扮演着"启动管理者"的角色。
2.bootloader的用途
1.在启动应用程序之前，对硬件外设进行初始化，可以在某种程度上做到应用层和硬件层分离的作用
2.在启动时对硬件或者Mcu自身进行检测，在运行程序之前对异常状态进行警报
3.通过Bootloader实现在线升级，第一，接收客户端软件发来的程序；第二将接收到的程序写入mcu的flash中，片内flash编程；第二，跳转到APP运行
3.S32K144的Bootloader的分配
1.S32k144的Flash容量
2.MCU上电复位流程
3.地址分配
Bootloader 分配
App Flash分配表
向量表重映射，之前失效
4.实验流程
通过按键从bootloader跳转APP
5.S32 编译器软件配置
1. 解锁flash默认配置
进人构建配置
使能Flash配置，取消RAM勾选
配置ld文件的MEMORY区
bootloader针对性修改 32k
app 空间分配 256k
6.部分代码
1.bootloader应用程序的代码：
javascript
* IO配置
* KEY1 PTC12
* KEY2 PTC13
* KEY3 PTB2
* LED1 PTD16
* LED2 PTD15
* LED3 PTD1
* LED4 PTD0
*/
#include "Cpu.h"
#include "delay.h"
#include "uart.h"
#include"key.h"
#include"oled.h"
#include <stdio.h>
volatile int exit_code = 0;
#define LED1(x) PINS_DRV_WritePin(PTD,16,!x);
#define LED2(x) PINS_DRV_WritePin(PTD,15,!x);
#define LED3(x) PINS_DRV_WritePin(PTD,1,!x);
#define LED4(x) PINS_DRV_WritePin(PTD,0,!x);
#define APP_START_ADDRESS 0x00008000 //应用程序起始地址
// Bootup application function
void Bootup_Application(uint32_t appEntry, uint32_t appStack)
{
static void (*jump_to_application)(void); //指向应用函数的指针
static uint32_t stack_pointer; //应用程序栈指针
jump_to_application = (void (*)(void))appEntry; //函数指针指向应用程序的复位向量表地址,强转函数指针
stack_pointer = appStack; //应用程序栈指针赋值
S32_SCB->VTOR = (uint32_t) APP_START_ADDRESS; //设置中断向量表地址为应用程序的起始地址
__asm volatile ("cpsie i" : : : "memory"); // 关闭全局中断
__asm volatile ("msr msp, %0\n" : : "r" (stack_pointer): "sp"); //设置主栈指针
__asm volatile ("msr psp, %0\n" : : "r" (stack_pointer): "sp"); //设置进程栈指针
jump_to_application(); //跳转到应用程序的复位向量表地址执行应用程序
}
int main(void)
{
/* Write your local variable definition here */
uint8_t pinstate;
int MCU_Freq;
uint32_t appEntry,appStack; //应用程序入口地址和栈指针地址
/*** Processor Expert internal initialization. DON'T REMOVE THIS CODE!!! ***/
#ifdef PEX_RTOS_INIT
PEX_RTOS_INIT(); /* Initialization of the selected RTOS. Macro is defined by the RTOS component. */
#endif
/*** End of Processor Expert internal initialization. ***/
CLOCK_SYS_Init(g_clockManConfigsArr, CLOCK_MANAGER_CONFIG_CNT,g_clockManCallbacksArr, CLOCK_MANAGER_CALLBACK_CNT);
CLOCK_SYS_UpdateConfiguration(0U, CLOCK_MANAGER_POLICY_AGREEMENT);
MCU_Freq = delay_init();//初始化delay函数
PINS_DRV_Init(NUM_OF_CONFIGURED_PINS, g_pin_mux_InitConfigArr); //初始化IO
I2C_MasterInit(&i2c1_instance, &i2c1_MasterConfig0);//初始化I2C外设,用于OLED通讯
LPUART_DRV_Init(INST_LPUART1, &lpuart1_State, &lpuart1_InitConfig0); //初始化串口
oled_init(); //OLED配置参数初始化
OLED_TITLE((uint8_t*)"S32K144",(uint8_t*)"01_BASE");//OLED显示标题
u1_printf("初始化完毕,MCU运行频率为 %d Mhz \r\n",MCU_Freq);
while(1)
{
pinstate = KEY_Proc (0);
if(pinstate ==BTN1_PRES )
{
u1_printf("KEY1 Pressed 2s enter app\r\n");
u1_printf("Enter App\r\n");
u1_printf("in 2 seconds\r\n");
delay_ms(1000);
u1_printf("in 1 seconds\r\n");
delay_ms(1000);
u1_printf("in 0 seconds\r\n");
appStack = *(uint32_t *)(APP_START_ADDRESS + 0x00); //读取应用程序栈指针地址
appEntry = *(uint32_t *)(APP_START_ADDRESS + 0x04); //读取应用程序入口地址
Bootup_Application(appEntry,appStack); //跳转到应用程序
}
}
/*** Don't write any code pass th5is line, or it will be deleted during code generation. ***/
/*** RTOS startup code. Macro PEX_RTOS_START is defined by the RTOS component. DON'T MODIFY THIS CODE!!! ***/
#ifdef PEX_RTOS_START
PEX_RTOS_START(); /* Startup of the selected RTOS. Macro is defined by the RTOS component. */
#endif
/*** End of RTOS startup code. ***/
/*** Processor Expert end of main routine. DON'T MODIFY THIS CODE!!! ***/
for(;;) {
if(exit_code != 0) {
break;
}
}
return exit_code;
/*** Processor Expert end of main routine. DON'T WRITE CODE BELOW!!! ***/
} /*** End of main routine. DO NOT MODIFY THIS TEXT!!! ***/编译后：未超出32k空间
2.app代码
javascript
* IO配置
* KEY1 PTC12
* KEY2 PTC13
* KEY3 PTB2
* LED1 PTD16
* LED2 PTD15
* LED3 PTD1
* LED4 PTD0
*/
#include "Cpu.h"
#include "delay.h"
#include "uart.h"
#include"key.h"
#include"oled.h"
volatile int exit_code = 0;
#define LED1(x) PINS_DRV_WritePin(PTD,16,!x);
#define LED2(x) PINS_DRV_WritePin(PTD,15,!x);
#define LED3(x) PINS_DRV_WritePin(PTD,1,!x);
#define LED4(x) PINS_DRV_WritePin(PTD,0,!x);
int main(void)
{
/* Write your local variable definition here */
uint8_t pinstate;
int MCU_Freq;
/*** Processor Expert internal initialization. DON'T REMOVE THIS CODE!!! ***/
#ifdef PEX_RTOS_INIT
PEX_RTOS_INIT(); /* Initialization of the selected RTOS. Macro is defined by the RTOS component. */
#endif
/*** End of Processor Expert internal initialization. ***/
CLOCK_SYS_Init(g_clockManConfigsArr, CLOCK_MANAGER_CONFIG_CNT,g_clockManCallbacksArr, CLOCK_MANAGER_CALLBACK_CNT);
CLOCK_SYS_UpdateConfiguration(0U, CLOCK_MANAGER_POLICY_AGREEMENT);
MCU_Freq = delay_init();//初始化delay函数
PINS_DRV_Init(NUM_OF_CONFIGURED_PINS, g_pin_mux_InitConfigArr); //初始化IO
I2C_MasterInit(&i2c1_instance, &i2c1_MasterConfig0);//初始化I2C外设,用于OLED通讯
LPUART_DRV_Init(INST_LPUART1, &lpuart1_State, &lpuart1_InitConfig0); //初始化串口
LED1(0);LED2(0);LED3(0);LED4(0);//LED熄灭
oled_init(); //OLED配置参数初始化
OLED_TITLE((uint8_t*)"S32K144",(uint8_t*)"01_BASE");//OLED显示标题
u1_printf("初始化完毕,MCU运行频率为 %d Mhz \r\n",MCU_Freq);
while(1)
{
u1_printf("App Running...\r\n");
PINS_DRV_TogglePins(PTD, 1 << 0);
delay_ms(1000);
u1_printf("App Running...\r\n");
PINS_DRV_TogglePins(PTD, 1 << 1);
delay_ms(1000);
}
/*** Don't write any code pass th5is line, or it will be deleted during code generation. ***/
/*** RTOS startup code. Macro PEX_RTOS_START is defined by the RTOS component. DON'T MODIFY THIS CODE!!! ***/
#ifdef PEX_RTOS_START
PEX_RTOS_START(); /* Startup of the selected RTOS. Macro is defined by the RTOS component. */
#endif
/*** End of RTOS startup code. ***/
/*** Processor Expert end of main routine. DON'T MODIFY THIS CODE!!! ***/
for(;;) {
if(exit_code != 0) {
break;
}
}
return exit_code;
/*** Processor Expert end of main routine. DON'T WRITE CODE BELOW!!! ***/
} /*** End of main routine. DO NOT MODIFY THIS TEXT!!! ***/7.实验现象
将两份代码都下载进芯片中，芯片先进入bootloader.main 从定向到0x8000
再指向app_main
