由于自己买的开发板的norflash坏了,板子剩下了nandflash了,还想玩开发板,就开始我的裸奔了,开始去了解nandflash启动原理,arm2410是从nandflash前4k空间复制到arm内部4kRAM空间当中运行.知道原理以后我写裸奔程序都不超过4k程序,就可以做跑马灯,rs232驱动,rtc程序是足够了.一开始 我用的软件是ads1.2,只能抄写别人 程序,程序当中有一个init2410.s里面有一大堆的汇编语言,看的我眼花撩乱,我也只能硬着头皮看下去,基本上能看懂了个大概. .s文件主要功能就是程序的开始和对中断向量进行描述,同时想main()函数跳转,跳到c语言当中运行.后来我做跑马灯时候,我把.s文件压缩成3句话,把没有用的语句都删了.一般的初试化函数都在2410lib.c文件当中,里面有串口初试化,端口初始化,等其他初始化.裸奔中我觉的最有成就感的是外部中断的实现和3.5寸lcd显示我的相册.先说一下我外部中断的实现.
b HandlerUndef ;handler for Undefined mode
b HandlerSWI ;handler for SWI interrupt b HandlerPabort ;handler for PAbort b HandlerDabort ;handler for DAbort b . ;reserved b HandlerIRQ ;handler for IRQ interrupt b HandlerFIQ ;handler for FIQ interrupt上面是中断向量表.
IsrIRQ
sub sp,sp,#4 ;reserved for PC stmfd sp!,{r8-r9} ldr r9,=INTOFFSET ldr r9,[r9] ldr r8,=HandleEINT0 add r8,r8,r9,lsl #2 ldr r8,[r8] str r8,[sp,#8] ldmfd sp!,{r8-r9,pc}普通中断表的指针.
InitStacks
;Don't use DRAM,such as stmfd,ldmfd...... ;SVCstack is initialized before ;Under toolkit ver 2.5, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1' mrs r0,cpsr bic r0,r0,#MODEMASK orr r1,r0,#UNDEFMODE|NOINT msr cpsr_cxsf,r1 ;UndefMode ldr sp,=UndefStack orr r1,r0,#ABORTMODE|NOINT msr cpsr_cxsf,r1 ;AbortMode ldr sp,=AbortStackorr r1,r0,#IRQMODE|NOINT
msr cpsr_cxsf,r1 ;IRQMode ldr sp,=IRQStack orr r1,r0,#FIQMODE|NOINT msr cpsr_cxsf,r1 ;FIQMode ldr sp,=FIQStackbic r0,r0,#MODEMASK|NOINT
orr r1,r0,#SVCMODE msr cpsr_cxsf,r1 ;SVCMode ldr sp,=SVCStack ;USER mode has not be initialized. mov pc,lr ;The LR register won't be valid if the current mode is not SVC mode. 中断的栈问题AREA RamData, DATA, READWRITE
^ _ISR_STARTADDRESS
HandleReset # 4 HandleUndef # 4 HandleSWI # 4 HandlePabort # 4 HandleDabort # 4 HandleReserved # 4 HandleIRQ # 4 HandleFIQ # 4;Don't use the label 'IntVectorTable',
;The value of IntVectorTable is different with the address you think it may be. ;IntVectorTable HandleEINT0 # 4 HandleEINT1 # 4 HandleEINT2 # 4 HandleEINT3 # 4 HandleEINT4_7 # 4 HandleEINT8_23 # 4 HandleRSV6 # 4 HandleBATFLT # 4 HandleTICK # 4 HandleWDT # 4 HandleTIMER0 # 4 HandleTIMER1 # 4 HandleTIMER2 # 4 HandleTIMER3 # 4 HandleTIMER4 # 4 HandleUART2 # 4 HandleLCD # 4 HandleDMA0 # 4 HandleDMA1 # 4 HandleDMA2 # 4 HandleDMA3 # 4 HandleMMC # 4 HandleSPI0 # 4 HandleUART1 # 4 HandleRSV24 # 4 HandleUSBD # 4 HandleUSBH # 4 HandleIIC # 4 HandleUART0 # 4 HandleSPI1 # 4 HandleRTC # 4 HandleADC # 4END
中断具体表.static void __irq KeyISR(void)
{ U8 key ;rGPGCON = rGPGCON & (~((3<<22)|(3<<6))) | ((0<<22)|(0<<6)) ; //GPG11,3 set input
rGPFCON = rGPFCON & (~((3<<4)|(3<<0))) | ((0<<4)|(0<<0)) ; //GPF2,0 set input if(rINTPND==BIT_EINT8_23) { ClearPending(BIT_EINT8_23); if(rEINTPEND&(1<<11)) { //puts("Interrupt eint11 occur..."); rEINTPEND |= 1<< 11; } if(rEINTPEND&(1<<19)) { //puts("Interrupt eint19 occur..."); rEINTPEND |= 1<< 19; } } else if(rINTPND==BIT_EINT0) { //puts("Interrupt eint0 occur..."); ClearPending(BIT_EINT0); } else if(rINTPND==BIT_EINT2) { //puts("Interrupt eint2 occur..."); ClearPending(BIT_EINT2); }//查询按键键值
key = Key_Scan() ; if( key != 0xff ) printf( "Interrupt occur... K%d is pressed!\n", key ) ;//Beep( 2000, 3000 ) ;
//重新初始化IO口
rGPGCON = rGPGCON & (~((3<<12)|(3<<4))) | ((1<<12)|(1<<4)) ; //GPG6,2 set output rGPGDAT = rGPGDAT & (~((1<<6)|(1<<2))); //GPG6,2 output 0 rGPECON = rGPECON & (~((3<<26)|(3<<22))) | ((1<<26)|(1<<22)); //GPE13,11 set output rGPEDAT = rGPEDAT & (~((1<<13)|(1<<11))); //GPE13,11 output 0 rGPGCON = rGPGCON & (~((3<<22)|(3<<6))) | ((2<<22)|(2<<6)) ; //GPG11,3 set EINT rGPFCON = rGPFCON & (~((3<<4)|(3<<0))) | ((2<<4)|(2<<0)) ; //GPF2,0 set EINT } 中断子函数,有四个中断源;实际上是三个中断源,在第三个中断分出了两个中断.中断可能初学者看的迷迷糊糊.好了中断就讲在这里.现在讲关于lcd显示动态的相册,由于照片的数据结构一定大于4k空间,所以在nandflash纯裸奔是不可能的.这个问题困饶我了很久,后来根据wince和linux启动的原理,我用bootloader(vivi)来启动我lcd裸奔程序,然后固化到nandflash当中即ce区或则是 kernel区.
Lcd_Port_Init();
puts("linshenghuan"); Lcd_Init(); Lcd_EnvidOnOff(1); //turn on vedioDelayMs();
Lcd_ClearScr(0x00); //fill all screen with some color DelayMs(); Lcd_ClearScr(0xF1F1); DelayMs(); Lcd_ClearScr(0x1F1F); DelayMs(); Lcd_ClearScr(0x00); Paint_Bmp( 0,0,240,320, xyx_240_320 ) ; //paint a bmp