四大驱动之-触摸屏（小例子-裸版）
当我们在触摸屏上按下一个键的时候：打印down,x,y坐标，放手后打印：
test.c,up.h,Makefile,vector.S
#include "up.h"int (*printf)(char *,...) = 0x57e11d4c;
void do_irq();
int main()
{
*(unsigned long *)0x56000000 = do_irq; //开辟空间，我们把函数入在这里。
__asm__ __volatile__(
"mrs r0,cpsr\n"
"bic r0,r0,#0x80\n"
"msr cpsr,r0\n"
);
VIC1INTSELECT &= ~(1<<30);//VIC1INTSELECT = 0<<30;第62号中断：62－32＝30
VIC1INTSELECT &= ~(1<<31);//VIC1INTSELECT = 0<<30;第63号中断：63－32＝31
VIC1INTENABLE |= (1<<30);//中断使能
VIC1INTENABLE |= (1<<31);//中断使能
ADCTSC=0xd3;//打开down中断
return 0;
}
//down->adc->up->down
void do_irq()
{
if(VIC1RAWINTR&(1<<30))
{
ADCCLRINTPNDNUP =1;
if(ADCUPDN &1)
{
printf("down\n");
//ADCTSC = (1<<8)|0xd3;
//if down adc interrupt open
ADCCON = 1 | (30<<6)|(1<<14)|(1<<16);
ADCTSC |= 4;
}
else if(ADCUPDN & (1<<1))
{
printf("up\n");
//wait down
ADCTSC=0xd3;
}
ADCUPDN =0;//这个一定要手动清除
}
if(VIC1RAWINTR & (1<<31))
{
ADCCLRINT = 1;
printf("x is %d\n",ADCDAT0 & 0xfff);
printf("x is %d\n",ADCDAT1 & 0xfff);
//wait up
ADCTSC = (1<<8)|0xd3;
}
}
up.h:
#define VIC0IRQSTATUS (*(volatile unsigned long *)0x71200000)
#define VIC0RAWINTR (*(volatile unsigned long *)0x71200008)
#define VIC0INTSELECT (*(volatile unsigned long *)0x7120000C)
#define VIC0INTENABLE (*(volatile unsigned long *)0x71200010)
#define VIC0SOFTINT (*(volatile unsigned long *)0x71200018)
#define VIC1IRQSTATUS (*(volatile unsigned long *)0x71300000)
#define VIC1RAWINTR (*(volatile unsigned long *)0x71300008)
#define VIC1INTSELECT (*(volatile unsigned long *)0x7130000C)
#define VIC1INTENABLE (*(volatile unsigned long *)0x71300010)
#define VIC1SOFTINT (*(volatile unsigned long *)0x71300018)
#define WTCON (*(volatile unsigned long *)0x7E004000)
#define WTDAT (*(volatile unsigned long *)0x7E004004)
#define WTCNT (*(volatile unsigned long *)0x7E004008)
#define WTCLRINT (*(volatile unsigned long *)0x7E00400C)
#define ADCCON (*(volatile unsigned long *)0x7E00B000)
#define ADCTSC (*(volatile unsigned long *)0x7E00B004)
#define ADCDLY (*(volatile unsigned long *)0x7E00B008)
#define ADCDAT0 (*(volatile unsigned long *)0x7E00B00C)
#define ADCDAT1 (*(volatile unsigned long *)0x7E00B010)
#define ADCUPDN (*(volatile unsigned long *)0x7E00B014)
#define ADCCLRINT (*(volatile unsigned long *)0x7E00B018)
#define ADCCLRINTPNDNUP (*(volatile unsigned long *)0x7E00B020)
vector.S
当发生中断时候 ，我们处理器进入异常向量表中：再从b irq中跳到，我们的irq中：
b reset
b und
b swi
b pre_abt
b data_abt
.word 0x0
b irq
b fiq
reset:
und:
mov sp, #0x56000000
stmfd sp!, {r0-r12, lr}
ldr r2, printf
ldr r0, =string_und
blx r2
mov sp, #0x56000000
ldmea sp, {r0-r12, pc}^
string_und:
.asciz "undefined\n"
.align 2
swi:
mov sp, #0x56000000
stmfd sp!, {r0-r12, lr}
ldr r1, [lr, #-4]
and r1, r1, #0xffffff
ldr r0, =string
ldr r2, printf
blx r2
mov sp, #0x56000000
ldmea sp, {r0-r12, pc}^
pre_abt:
mov sp, #0x56000000
sub lr, lr, #4
stmfd sp!, {r0-r12, lr}
mov sp, #0x56000000
ldmea sp, {r0-r12, pc}^
data_abt:
mov sp, #0x56000000
sub lr, lr, #4
stmfd sp!, {r0-r12, lr}
ldr r0, =string_data
ldr r2, printf
blx r2
mov sp, #0x56000000
ldmea sp, {r0-r12, pc}^
string_data:
.asciz "data\n"
.align 2
irq:
mov sp, #0x56000000 //开辟我们栈
sub lr, lr, #4
stmfd sp!, {r0-r12, lr} //保护现场
mov r1, #0x56000000
ldr r0, [r1]
blx r0 //跳到0x56000000 中保存的do_irq中的函数中执行：
//ldr r0, =0x7E00400C
//mov r1, #100
//str r1, [r0]
//
//ldr r0, =wdt_string
//ldr r2, printf
//blx r2
mov sp, #0x56000000 //恢复现场
ldmea sp, {r0-r12, pc}^
wdt_string:
.asciz "wang wang wang\n"
.align 2
fiq:
mov sp, #0x56000000
sub lr, lr, #4
stmfd sp!, {r0-r12, lr}
mov sp, #0x56000000
ldmea sp, {r0-r12, pc}^
printf:
.word 0x57e11d4c
string:
.asciz "swi %x\n"
.align 2
Makefile:
all:
arm-none-linux-gnueabi-gcc test.c -c -o test.o
arm-none-linux-gnueabi-ld -Ttext=0x50000000 test.o -o test
arm-none-linux-gnueabi-objcopy -Ielf32-littlearm -Obinary test /tftpboot/test.bin
arm-none-linux-gnueabi-gcc -c vector.S -o vector.o
arm-none-linux-gnueabi-ld -Ttext=0x0 vector.o -o vector
arm-none-linux-gnueabi-objcopy -Ielf32-littlearm -Obinary vector /tftpboot/vector.bin
clean:
rm -rf test.o test /tftpboot/test.bin
rm -rf vector.o vector /tftpboot/vector.bin