外部按鍵中斷

1、中斷配置一：設(shè)置匯編頭文件，設(shè)置中斷向量表例如 b SYS_RST_HANDLER b UDF_IND_HANDLER b SWI_SVC_HANDLER b INS_ABT_HANDLER b DAT_ABT_HANDLER b IRQ_SVC_HANDLER b FIQ_SVC_HANDLER /中斷向量表設(shè)置/正常函數(shù) ldr r13, =4028 bl clock_init b ledMain/中斷處理操作SYS_RST_HANDLER: b SYS_RST_HANDLERUDF_IND_HANDLER: b UDF_IND_HANDLERSWI_SVC_HANDLER: b SWI_

2、SVC_HANDLERINS_ABT_HANDLER: b INS_ABT_HANDLERDAT_ABT_HANDLER: b DAT_ABT_HANDLER ;跳轉(zhuǎn)IRQ_SVC_HANDLER: sub lr, lr, #4 計算并保存返回地址到R14里 stmdb sp!, r0-r12,lr /保護(hù)寄存器的值壓入堆棧 注意，此時的sp是中斷模式的sp ldr lr, =int_return /將int_return的地址存入R14 ldr pc, =feeddog /跳轉(zhuǎn)到相應(yīng)函數(shù)地址int_return:/將寄存器，pc，cpsR的值恢復(fù)到中斷前 ldmia sp!, r0-r12,

3、pc / 中斷返回, 表示將spsr的值復(fù)制到cpsrFIQ_SVC_HANDLER: b FIQ_SVC_HANDLER二，配置相應(yīng)的中斷寄存器例如：#define SRCCPND (*(volatile unsigned *)0X4A000000)/源掛起（SRCPND）寄存器配置#define INTMOD (*(volatile unsigned *)0X4A000004)/中斷模式（INTMOD）寄存器配置#define INTMSK (*(volatile unsigned *)0X4A000008)/中斷屏蔽（INTMSK）寄存器默認(rèn)即可#define PRIORITY (*(v

4、olatile unsigned *)0X4A00000C)/優(yōu)先級寄存器（PRIORITY）#define INTPND (*(volatile unsigned *)0X4A000010)/中斷掛起（INTPND）寄存器#define INTOFFSET (*(volatile unsigned *)0x4A000014)/中斷偏移（INTOFFSET）寄存器#define SUBSRCPND (*(volatile unsigned *)0X4A000018)/次級源掛起（SUBSRCPND）寄存器#define INTSUBMSK (*(volatile unsigned *)0X4A00001C)/中斷次級屏蔽（INTSUBMSK）寄存器編寫中斷處理函數(shù)1.在中斷函數(shù)中通過讀取中斷偏移（INTOFFSET）寄存器的值來判斷中斷號2.在中斷處理函數(shù)中要對源掛起（SRCPND）寄存器、次級源掛起（SUBSRC