2022年10月14日 | min2440 uart中断模式(非fifo模式)

Makefile

uart_interrupt.bin : start.s function.c

arm-linux-gcc -g -c -o start.o start.s

arm-linux-gcc -g -c -o function.o function.c

arm-linux-ld -Ttext 0x30000000 -g start.o function.o -o uart_interrupt.elf

arm-linux-objcopy -O binary -S uart_interrupt.elf uart_interrupt.bin

arm-linux-objdump -D -m arm uart_interrupt.elf > uart_interrupt.dis

clean : 

rm -f *.o *.bin *.dis

start.s

.text

.global _start

_start:

b reset

b .

b .

b .

b .

b .

b handle_irq

b .

reset:

@shut down the watchdog

ldr r0, =0x53000000

ldr r1, =0x00000000

str r1, [r0]

@init the stack address

ldr r1, =4096

ldr r0, =0x40000000

add sp, r1, r0

bl init_led

bl init_clock

bl display_led1

bl init_sdram

bl display_led2

@reset the stack pointer

ldr sp, =0x34000000 @change stack to the end of sdram

msr cpsr_c, #0xd2

ldr sp, =0x33F00000 @change the stack pointer of irq mode

msr cpsr_c, #0xd3 @change cpu back to svc mode

bl copy_code2sdram @copy 8KB data from norflash to sdram

ldr pc, =on_sdram

on_sdram:

bl init_uart0

bl init_interrupt

msr cpsr_c, #0x53 @clear the irq disable bit in cpsr

bl main

halt_loop:

b halt_loop

handle_irq:

sub lr, lr, #4 @set the address(int main function) to return when handle_irq ends

stmdb sp!, {r0-r12, lr} @save the universal registers and lr_irq to the stack of irq mode

bl handle_irq_func @branch to the irq handleing function achieved in function.c 

ldmia sp!, {r0-r12, pc}^ @resume the universal registers and save lr to pc while copying spsr to cpsr

function.c

//gpb registers

#define GPBCON (*((volatile unsigned long *)0x56000010))

#define GPBDAT (*((volatile unsigned long *)0x56000014))

//mem controler registers

#define BWSCON (*((volatile unsigned long *)0x48000000))

#define BANKCON0 (*((volatile unsigned long *)0x48000004))

#define BANKCON1 (*((volatile unsigned long *)0x48000008))

#define BANKCON2 (*((volatile unsigned long *)0x4800000C))

#define BANKCON3 (*((volatile unsigned long *)0x48000010))

#define BANKCON4 (*((volatile unsigned long *)0x48000014))

#define BANKCON5 (*((volatile unsigned long *)0x48000018))

#define BANKCON6 (*((volatile unsigned long *)0x4800001C))

#define BANKCON7 (*((volatile unsigned long *)0x48000020))

#define REFRESH (*((volatile unsigned long *)0x48000024))

#define BANKSIZE (*((volatile unsigned long *)0x48000028))

#define MRSRB6 (*((volatile unsigned long *)0x4800002C))

#define MRSRB7 (*((volatile unsigned long *)0x48000030))

//gpg registers

#define GPGCON (*((volatile unsigned long *)0x56000060))

//gph registers

#define GPHCON (*((volatile unsigned long *)0x56000070))

#define GPHUP (*((volatile unsigned long *)0x56000078))

//interrupt related registers

#define EINTMASK (*((volatile unsigned long *)0x560000A4))

#define INTMSK (*((volatile unsigned long *)0x4A000008))

#define INTMOD (*((volatile unsigned long *)0x4A000004))

#define INTOFFSET (*((volatile unsigned long *)0x4A000014))

#define SRCPND (*((volatile unsigned long *)0x4A000000))

#define INTPND (*((volatile unsigned long *)0x4A000010))

#define EINTPEND (*((volatile unsigned long *)0x560000A8))

#define INTSUBMSK (*((volatile unsigned long *)0x4A00001C))

#define SUBSRCPND (*((volatile unsigned long *)0x4A000018))

//PLL related registers

#define LOCKTIME (*((volatile unsigned long *)0x4C000000))

#define MPLLCON (*((volatile unsigned long *)0x4C000004))

#define CLKDIVN (*((volatile unsigned long *)0x4C000014))

//uart related registers

#define ULCON0 (*((volatile unsigned long *)0x50000000))

#define UCON0 (*((volatile unsigned long *)0x50000004))

#define UFCON0 (*((volatile unsigned long *)0x50000008))

#define UMCON0 (*((volatile unsigned long *)0x5000000C))

#define UBRDIV0 (*((volatile unsigned long *)0x50000028))

#define UTRSTAT0 (*((volatile unsigned long *)0x50000010))

#define URXH0 (*((volatile unsigned char *)0x50000024))

#define UTXH0 (*((volatile unsigned char *)0x50000020))

void blink(void);

void display_led(int);

void init_sdram(){

BWSCON = 0x22011110;

BANKCON0 = 0x00000700;

BANKCON1 = 0x00000700;

BANKCON2 = 0x00000700;

BANKCON3 = 0x00000700;

BANKCON4 = 0x00000700;

BANKCON5 = 0x00000700;

BANKCON6 = 0x00018005;

BANKCON7 = 0x00018005;

//when hcls is 12MHz

//REFRESH = 0x008C07A3;

//when hckl is 100MHz

REFRESH = 0x008C04F4; 

BANKSIZE = 0x000000B1;

MRSRB6 = 0x00000030;

MRSRB7 = 0x00000030;

}

void init_interrupt(){

//set the gpio pins of the six keys to interrupt mode 

GPGCON = (1<<(0*2+1) | 1<<(3*2+1) | 1<<(5*2+1) | 1<<(6*2+1) | 1<<(7*2+1) | 1<<(11*2+1));

//set EINTMASK register to enable external interrupt

EINTMASK &= (~(1<<8 | 1<<11 | 1<<13 | 1<<14 | 1<<15 | 1<<19));

//set INTMSK register to enable eint8_23

INTMSK &= (~(1<<5));

//enable uart0 interrupt

INTMSK &= (~(1<<28));

//enable rxd0 interrupt and txd0 interrupt

INTSUBMSK &= (~(0b11));

//set INTMOD register to set int8_23 to irq mode

INTMOD &= (~(1<<5));

}

void init_uart0(){

GPHCON |= ( (1<<5) | (1<<7) );

GPHCON &= ~( (1<<4) | (1<<6) );

GPHUP |= ( (1<<2) | (1<<3) );

ULCON0 = 0x03; //8 data bits, 1 stop bits, no check

UCON0 = 0X05; //polling mode or interrupt mode

UFCON0 = 0x00;

UMCON0 = 0x00;

UBRDIV0 = 0x1A; //bit rate is 115200(pclk is 50MHz)

}

unsigned char getchar_uart0(){

blink();

while( !(UTRSTAT0&1) );

return URXH0;

}

void putchar_uart0(unsigned char ch){

while( !(UTRSTAT0&4) );

UTXH0 = ch;

blink();

}

void handle_key(){

int eint_v;

eint_v = EINTPEND;

if(eint_v & (1<<8)){

display_led(1);

EINTPEND = 1<<8;

return;

}

if(eint_v & (1<<11)){

display_led(2);

EINTPEND = 1<<11;

return;

}

if(eint_v & (1<<13)){

display_led(3);

EINTPEND = 1<<13;

return;

}

if(eint_v & (1<<14)){

display_led(4);

EINTPEND = 1<<14;

return;

}

if(eint_v & (1<<15)){

display_led(5);

EINTPEND = 1<<15;

return;

}

if(eint_v & (1<<19)){

display_led(6);

EINTPEND = 1<<19;

return;

}

}

void handle_uart0_interrupt(){

unsigned char ch;

if(SUBSRCPND & (1<<0)){ //rxd0 interrupt

ch = getchar_uart0();

SUBSRCPND |= (1<<0);

putchar_uart0(ch);

}

else if(SUBSRCPND & (1<<1)){ //txd0 itnerrupt

//do nothing

SUBSRCPND |= (1<<1);

}

}

void handle_irq_func(){

int offset_v;

offset_v = INTOFFSET;

switch(offset_v){

case 5: //external interrupt

handle_key();

break;

case 28:

handle_uart0_interrupt();

break;

default:

break;

}

//clear the interrupt

SRCPND = 1< INTPND = 1<}

void delay(int n){

int i, j;

for(i=0; i for(j=0; j<1000; j++){}

}

}

void blink(){

GPBDAT = 0xffffffff;

GPBDAT = 0x00000000;

delay(1);

GPBDAT = 0xffffffff;

delay(1);

}

void display_led1(){

GPBDAT = ~(1<<5);

delay(1);

}

void display_led2(){

GPBDAT = ~(3<<5);

delay(1);

}

void display_led3(){

GPBDAT = ~(7<<5);

delay(1);

}

void display_led4(){

GPBDAT = ~(15<<5);

delay(1);

}

void display_led(int n){

GPBDAT = ~(n<<5);

}

void copy_code2sdram(){

int size, i;

unsigned char *src, *des;

size = 8*1024;

des = (unsigned char*)(0x30000000);

src = (unsigned char *)(0x00000000);

for(i=0; i *(des++) = *(src++);

}

}

void init_led(){

GPBCON = 0x00015400;

GPBDAT &= ~(0x0f<<5);

}

//initialize the clock of soc

void init_clock(){

LOCKTIME = 0xffffffff;  

    CLKDIVN = 0X03; //fclk:hclk:pclk=1:2:4  

    __asm__  

    (  

        "mrc    p15, 0, r1, c1, c0, 0n"  

        "orr    r1, r1, #0xc0000000n"  

        "mcr    p15, 0, r1, c1, c0, 0n"      

    );  

    MPLLCON = (92<<12)|(1<<4)|(2<<0); //fclk=200M, hclk=100M, pclk=50M 

}

/*

int main(void){

int i;

GPBCON = 0x00015400;

i = 0;

while(1){

GPBDAT = ~(1<<(i+5));

delay(1);

i = (i+1)%4;

}

return 0;

}

*/

int main(void){

display_led3();

while(1){

//waiting for interrupt

}

return 0;

}