中斷硬件驅(qū)動(dòng)代碼分析

1、中斷硬件驅(qū)動(dòng)代碼分析ARM-Week-1Learn-lumit-Step-15.中斷按鈕實(shí)驗(yàn)1, int0_driver.cint int0_open( void )初始化IO端口專用寄存器/ set gpio's direction: set IOPMOD register mode bit to 0 = inputIOPMOD = IOPMOD & (0x00000100);即把IOPMOD的第8位（9端口）清零，也就是設(shè)置為輸入模式。/ unmask the switch interrupt .INTMSK &= (1<<21) | (1<<

2、;0); (1<<21) | (1<<0)=（10 0000 0000 0000 0000 0000|1）=01 1111 11111111 1111 1110也就是要把INTMSK的22位和0位清零（開啟中斷控制器，開啟外部中斷控制0）。return 0;int int0_ioctl( unsigned int cmd, unsigned long arg )switch( cmd )INT0_IO_ENABLE宏定義值為(1<<4)INT0_IO_ACTIVE_HIGH宏定義值為 (1<<3)INT0_IO_RISING_EDGE宏定義值為

3、(0x01)INT0_IO_FALLING_EDGE宏定義值為 (0x02)INT0_IO_BOTH_EDGE宏定義值為 (0x03)/ Enable interrupt request and Unmask PIO8 interruptcaseINT0_ENABLE_INTERRUPT:IOPCON |= INT0_IO_ENABLE; INT0_IO_ENABLE為1 0000 。把IO端口控制寄存器第4位置1，即開啟XIRQ0。break;/ clear int 0 pending interruptscaseINT0_CLEAR_INTERRUPT:INTPND |= INT0_MAS

4、K;INTO_MASK宏定義值為1，把INTPND第0位值1，即把外部中斷0清0。break;/ set rising edge interruptcaseINT0_RISING_EDGE_INTERRUPT: IOPCON|= INT0_IO_RISING_EDGE;設(shè)置中斷為上升沿觸發(fā)；break;/ set falling edge interruptcaseINT0_FALLING_EDGE_INTERRUPT: IOPCON|= INT0_IO_FALLING_EDGE;設(shè)置中斷為下降沿觸發(fā)；break;/ set both edge interruptcaseINT0_BOTH_E

5、DGE_INTERRUPT: IOPCON|= INT0_IO_BOTH_EDGE;設(shè)置中斷為下降/上升沿都觸發(fā)；break; / set as active highcaseINT0_ACTIVE_HIGH:IOPCON|= INT0_IO_ACTIVE_HIGH;設(shè)置中斷為電平觸發(fā)；break;default:break;return 0;2, startup.smov r0, #0xd2 ; make irq mode with all irqs disabledmsr cpsr_cxsf, r0MOV sp, #0x70000設(shè)置IRQ模式的棧指針。movr0, #0xd3 ; mak

6、e svc mode with all irqs disabledmsrcpsr_cxsf, r0 MOV sp, #0x80000設(shè)置SVC模式的棧指針。*; * Get the address of the C entry point.; *LDR lr, =_main保存_main的入口地址*; * Enable the interrupt while staying in the supervisor mode; *MOVr0, #Mode_Svc:OR:F_BitMSRcpsr_c, r0MOV pc, lrIMPORT do_irqEXPORT irq_handlerirq_handlerSUBlr, lr, #4 STMFDsp!, r0-r12, lr ; push r0-r12 register file and lr( pc return address )MRS r4, spsr STMFD sp!, r4 ; push current spsr_cxsf_irq ( =cpsr_svc )BLdo_irq ; goto C handlerLDMFD sp!, r4 ; get cpsr_svc from stackMSR spsr_cxsf, r4 ; prepare spsr_cxsf to retu