#include?<stm32mp1xx_gpio.h>
#include?<stm32mp1xx_exti.h>
#include?<stm32mp1xx_gic.h>
#include?<stm32mp1xx_rcc.h>
void?hal_gpio_init(void);
void?hal_exti_init(void);
void?hal_gicd_init(void);
void?hal_gicc_init(void);
extern?void?printf(const?char?*fmt,?...);
?
void?mydelay_ms(int?ms)
{
????int?i,?j;
????while(ms--)
????{
????????for?(i?=?0;?i?<?10000;?i++)
????????????for?(j?=?0;?j?<?10000;?j++);
????}
}
?
void?do_irq(void)
{
????unsigned?int?irq_num;
????irq_num?=?GICC.IAR?&?(0x3FF);
????switch(irq_num)
????{
????????case?38:
????????????//?中断处理程序，此处只打印一条语句
????????????printf("put?on?\n");
????????????EXTI.FPR1?|=?(0x1?<<?0);??????????//下降边沿挂起寄存器??写0防止一直进入
????????????GICD.ICPENDR[1]?|=?(0x1?<<?6);??????//?清除GICD层中断?挂起清除
????????????break;
????????case?39:
????????????break;
????}
????//?清除GICC层中断?将38号写进去结束
????GICC.EOIR?=?(GICC.EOIR?&?(~0x3FF))?|?irq_num;
}
?
void?hal_gpio_init(void)
{
????//?使能GPIOA组的时钟使能，?在??RCC_MP_AHB4ENSETR
????RCC.MP_AHB4ENSETR?|=?(0x1?<<?0);
????GPIOA->MODER?&=?(~0x3?<<?0);???????????????????//按键配置??????输入功能
????GPIOA->PUPDR?&=?~(0x3?<<?0);???????????????????//无上、下拉
}
/*
?*?PA0引脚对应的外部中断事件是EXTI[0]
?*?对应着Event?Input?0
?*?具体的外设和EXTI对应的关系在21.3章节
?*?按键中断设置为下降沿触发中断事件的检测
?*?*/
void?hal_exti_init(void)
{
????//?设置为下降沿触发选择寄存器
????EXTI.FTSR1?|=?(0x1?<<?0);
????//?设置外部中断选择寄存器?连接到PA0上
????EXTI.EXTICR1?&=?(~(0xff?<<?0));
????//?设置EXTI?CPU1唤醒中断屏蔽寄存器
????EXTI.C1IMR1?|=?(0x1?<<?0);
????//?设置EXTI?CPU1唤醒事件屏蔽寄存器
//??EXTI.C1EMR1?|=?(0x1?<<?0);
}
/*
?*?PA0引脚属于EXTI0
?*?EXTI0?对应的中断ID为?38
?*?对应关系在芯片手册的21.2章节
?*?*/
void?hal_gicd_init(void)
{
????GICD.ISENABLER[1]?|=?(0x1?<<?6);????????????????????????????????????????????????//中断号为38??GICD中断使能
????GICD.IPRIORITYR[9]?&=?~(0x1f?<<?19);
????GICD.IPRIORITYR[9]?|=??(0x10?<<?19);????????????????????????????????????????????//中断优先级,设置为16
????GICD.ITARGETSR[9]?|=?(0x3?<<?16);?????//选择处理器处理控制器转发的中断??但是为啥写0x3??????????????????????????????????????????//中断处理器目标寄存器
????GICD.CTLR?|=?(0x1?<<?0);????????????????????????????????????????????????????????//全局使能
????//由于默认38号外部中断用group?0?处理所以这里不用设置组别
}
void?hal_gicc_init(void)
{
????GICC.CTLR?|=?(0x1?<<?0);????????//?设置GICC层?中断全局使能寄存器??enable?group?0?interrupts
????GICC.PMR?|=?(0x1f?<<?3);????????//?设置GICC层?中断屏蔽寄存器?
}
?
int?main()
{
????hal_gpio_init();
????hal_gicc_init();
????hal_gicd_init();
????hal_exti_init();
?
????while(1)
????{
????}
????return?0;
}
汇编代码:
.text
.global?_start
_start:
????????b???????reset
????????ldr?????pc,_undefined_instruction
????????ldr?????pc,_software_interrupt
????????ldr?????pc,_prefetch_abort
????????ldr?????pc,_data_abort
????????ldr?????pc,_not_used
????????ldr?????pc,_irq?//跳转到_irq标志处
????????ldr?????pc,_fiq
_undefined_instruction:?.word??_undefined_instruction
_software_interrupt:????.word??_software_interrupt
_prefetch_abort:????????.word??_prefetch_abort
_data_abort:????????????.word??_data_abort
_not_used:??????????????.word??_not_used
_irq:???????????????????.word??irq_handler??//跳转到irq_handler标志处
_fiq:???????????????????.word??_fiq
//????mrc?p15,0,r0,c1,c1,2
//??movw??????r1,?#0x3fff
//??movt??????r1,?#0x0004
//??orr??r0,r0,r1
//????mcr??p15,0,r0,c1,c1,2
reset:
????ldr?r0,=?_start
????mcr?p15,0,r0,c12,c0,0???????//?通过协处理器将中断向量表地址定向到最前面的_start，如果一有IRQ发生,就跳到_start寻找irq异常
????????mrs?????r0,cpsr
????????bic?????r0,r0,#0x1f
????????orr?????r0,r0,#0xd3
????????msr?????cpsr,r0????????//??Enable?svc?mode?of?cpu
?
init_stack:
????????ldr?????r0,stacktop?????????/*get?stack?top?pointer*/
????/********svc?mode?stack********/
????????mov?????sp,r0
????????sub?????r0,#128*4??????????/*512?byte??for?irq?mode?of?stack*/
????/****irq?mode?stack**/
????????msr?????cpsr,#0xd2
????????mov?????sp,r0
????????sub?????r0,#128*4??????????/*512?byte??for?irq?mode?of?stack*/
????/***fiq?mode?stack***/
????????msr?????cpsr,#0xd1
????????mov?????sp,r0
????????sub?????r0,#0
????/***abort?mode?stack***/
????????msr?????cpsr,#0xd7
????????mov?????sp,r0
????????sub?????r0,#0
????/***undefine?mode?stack***/
????????msr?????cpsr,#0xdb
????????mov?????sp,r0
????????sub?????r0,#0
???/***?sys?mode?and?usr?mode?stack?***/
????????msr?????cpsr,#0x10
????????mov?????sp,r0?????????????/*1024?byte??for?user?mode?of?stack*/
?
????bl?main
????.align??4
????/****??swi_interrupt?handler??****/
?
????/****??irq_handler??****/
irq_handler:
????sub??lr,lr,#4???//因为三级流水线的原因,中断模式lr保存的地址的下下条指令的地址,如果我们从中断回来后想跳到下一条指令,那么这里需要人为的
????//对lr进行-4操作
????stmfd?sp!,{r0-r12,lr}//对r0-r12寄存器为IRQ和user模式的共有寄存器,转到IRQ模式之后需要将她们压栈保护现场,对lr进行压栈防止在下面指令中lr被修改就回不去中断之前的地方了
????.weak?do_irq
????bl??do_irq??//跳到中断处理函数中??这个处理函数是用c语言写的
????ldmfd?sp!,{r0-r12,pc}^?//1.将r0-r12出栈?2.将lr直接压到PC返回中断前的位置?3.^符号是将spsr寄存器中存好的中断之前的cpsr状态
????//给到user模式中的cpsr寄存器
stacktop:????.word??????stack+4*512
.data
stack:???.space??4*512
loop:
????b?loop
????.end
?
