2022年10月13日 | mini2440 IIC 裸机程序记录

调了两天终于把2440上面的IIC调通了，代码记录如下：

head.s

@this is a test program of uart using com0, the properties of com0 is the same as usual (115200,8, 1, n, n)

.text

.global _start

_start:

b Reset

b . @undefined instruction

b . @swi

b . @pregetch instruction

b . @data abort

b . @Reserved

b HandleIRQ @irq

b . @fiq

Reset:

ldr sp, =4096 @set the stack pointer of sys mode to 4096

bl disable_watchdog

bl init_led

bl init_sdram

bl copy_sdram

ldr pc, =on_sdram

on_sdram:

msr cpsr_c, #0xd2 @set cpu to irq mode

ldr sp, =3072 @set the stack pointer of irq mode to 3072

msr cpsr_c, #0xdf @reset cpu to sys mode

bl init_clock

mov r0, #1

mov r1, #10

bl blink

bl init_iic

mov r0, #2

mov r1, #10

bl blink

bl init_com0

mov r0, #3

mov r1, #10

bl blink

bl init_irq

msr cpsr_c, #0x5f @enable irq

bl main

b .

.ltorg

.ltorg

.ltorg

HandleIRQ:

sub lr, lr, #4

stmdb sp!, {r0-r12, lr}

ldr lr, =next

ldr pc, =interrupt_func

next:

ldmia sp!, {r0-r12, pc}^ @return to main

.ltorg

.ltorg

init.c

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

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

#define WTCON       (*((volatile unsigned long*)(0x53000000)))

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

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

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

#define TCFG0 (*((volatile unsigned long*)(0x51000000)))

#define TCFG1 (*((volatile unsigned long*)(0x51000004)))

#define TCNTB0 (*((volatile unsigned long*)(0x5100000C)))

#define TCON (*((volatile unsigned long*)(0x51000008)))

#define INTMSK (*((volatile unsigned long*)(0X4A000008)))

#define INTSUBMASK (*((volatile unsigned long*)(0X4A00001C)))

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

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

//control register of com0

#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)))

//the control register of sckl, sdat (IIC)

#define GPECON (*((volatile unsigned long*)(0x56000040)))

#define GPEUP (*((volatile unsigned long*)(0x56000048)))

#define IICCON (*((volatile unsigned long*)(0x54000000)))

#define IICSTAT (*((volatile unsigned long*)(0x54000004)))

//initilize GPB to output mode

void init_led()

{

GPBCON  &= (~(0xff<<10));

GPBCON  |= (0X55<<10);

}

void delay(int times)

{

int i, j;

for(i=0; i {

for(j=0; j<1000; j++);

}

}

//blink function is used to debug

void blink(int number, int delay_num)

{

GPBDAT |= (0X0F<<5);

GPBDAT &= (~(number<<5));

delay(delay_num);

GPBDAT |= (0X0F<<5);

delay(delay_num);

}

void disable_watchdog()

{

WTCON = 0;

}

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 

}

void init_sdram()

{

volatile unsigned long *p = (volatile unsigned long *)(0x48000000);

    p[0] = 0x22011110;     //BWSCON

    p[1] = 0x00000700;     //BANKCON0

    p[2] = 0x00000700;     //BANKCON1

    p[3] = 0x00000700;     //BANKCON2

    p[4] = 0x00000700;     //BANKCON3  

    p[5] = 0x00000700;     //BANKCON4

    p[6] = 0x00000700;     //BANKCON5

    p[7] = 0x00018005;     //BANKCON6

    p[8] = 0x00018005;     //BANKCON7

    p[9] = 0x008C04F4;    //REFRESH value is different than before, because the clock is different

    p[10] = 0x000000B1;     //BANKSIZE

    p[11] = 0x00000030;     //MRSRB6

    p[12] = 0x00000030;     //MRSRB7

}

void copy_sdram()

{

unsigned long* src = (unsigned long *)(0);

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

int i;

for(i=0; i<1024; i++)

{

des[i] = src[i];

}

}

void init_irq()

{

//enable interrupt of rxd0 txd0

INTSUBMASK &= (~(0b11));

//enable interrupt of uart0

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

//enable IIC interrupt

INTMSK &= (~(1<<27));

}

//initialize the IIC bus

void init_iic()

{

//set gpe[14:15] used for IIC

GPECON &= (~(0b1111<<28));

GPECON |= (0b1010<<28);

//enable the pulling up function

GPEUP &= (~(0b11<<14));

/*

0b00100111

[7] disable ack signal

[6] IICCLK=PCLK/16

[5] enable IIC rx interrupt and tx interrupt

[4] clear IIC interrupt

[3:0] tx clock = IICCLK/8 = 50000000/16/16 = 195.3125KHz

*/

IICCON = 0b00101111;

//enable IIC R/T ability

IICSTAT = 0x10;

}

void init_com0()

{

//set gph[2:3] used as txd and rxd for com0

GPHCON &= (~(0xff<<4));

GPHCON |= (0x0a<<4);

//disable pull up functon for gph[2:3]

GPHUP = 0x0c;

//set properties of com0

ULCON0 = 0b00000011;

//enable the rxd and txd, and interrupt will happen when con0 received data or the send buffer is empty in non-fifo mode

UCON0 = 0b00000101;

//disable fifo

UFCON0 = 0x00;

//disable fifo

UMCON0 = 0x00;

//set baud-rate to 115200

UBRDIV0 = (int)(50000000/(115200*16)) -1;

}

com0.c

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

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

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

#define SUBSRCPND (*((volatile unsigned long*)(0X4A000018)))

#define SRCPND (*((volatile unsigned long*)(0X4A000000)))

#define INTPND (*((volatile unsigned long*)(0X4A000010)))

#define IICSTAT (*((volatile unsigned long*)(0x54000004)))

#define IICDS (*((volatile unsigned long*)(0x5400000C)))

extern void blink(int, int);

extern unsigned char write_ack;

extern unsigned char iic_mode;

extern unsigned char read_over;

extern unsigned char read_data;

void put_char(char ch)

{

while (!(UTRSTAT0 & (1<<2)));

UTXH0 = ch;

}

unsigned char get_char()

{

while (!(UTRSTAT0 & (1<<0)));

return URXH0;

}

void put_string(char *string)

{

int i = 0;

while(string[i] != '')

put_char(string[i++]);

}

void com0_read(char *ch)

{

*ch = URXH0;

}

void com0_write(char ch)

{

UTXH0 = ch;

}

//the function to serve the uart0 interrupt

void interrupt_func()

{

//uart0 interrupt

if(INTPND & (1<<28))

{

char ch;

//rxd sub interrupt

if(SUBSRCPND & (1<<0))

{

com0_read(&ch);

if(ch == 'r')

{

com0_write('r');

com0_write('n');

}

else

{

com0_write(ch);

}

}

else if(SUBSRCPND & (1<<1)) //txd interrupt

{

}

//clear the interrupt of uart0

SUBSRCPND = SUBSRCPND;

SRCPND |= (1<<28);

INTPND = INTPND;

}

else if(INTPND & (1<<27)) //IIC interrupt

{

put_string("IIC interrupt!rn");

if(iic_mode) //write mode

{

if(!(IICSTAT&(1<<0)))

{

write_ack = 1;

put_string("get ack!rn");

}

else

{

write_ack = 0;

put_string("no ack!rn");

}

}

else //read mode

{

read_over = 1;

put_string("get datarn");

}

//clear the interrupt

SRCPND |= (1<<27);

INTPND = INTPND;

}

}

IIC.c

#define IICDS (*((volatile unsigned long*)(0x5400000C)))

#define IICSTAT (*((volatile unsigned long*)(0x54000004)))

#define IICCON (*((volatile unsigned long*)(0x54000000)))

extern void delay(int);

extern void put_string(char *);

//the ack signal form slave device

unsigned char write_ack = 0;

//the data read from IIC slave device

unsigned char read_data = 0;

//the mode of iic, 0----read mode , 1----write mode

unsigned char iic_mode = 0;

//the flag of whether reading is over

unsigned char read_over = 0;

/*

write one byte to slave device

salve_addr ---- the address of slave address

data_addr ---- the address of the byte writen by host

data ----- the writen data

*/

void iic_write(unsigned char slave_addr, int data_addr, unsigned char data)

{

slave_addr &= 0b11111110;

iic_mode = 1; //write mode

//send S signal and the slave address

write_ack = 0;

IICDS = slave_addr;

IICSTAT = 0xf0;

//wait the interrupt to change write_ack

while(!write_ack);

//send data_addr

write_ack = 0;

IICDS = data_addr;

IICCON = 0b00101111; //recover the transmission

while(!write_ack);

//send data

write_ack = 0;

IICDS = data;

IICCON = 0b00101111; //recover the transmission

while(!write_ack);

//send P signal

IICSTAT = 0xd0;

IICCON = 0b00101111; //recover the transmission

delay(3);

}

//read a byte from slave device

unsigned char iic_read(unsigned char slave_addr, int data_addr)

{

slave_addr &= 0b11111110;

iic_mode = 1; //write mode

//send S signal and the slave address

write_ack = 0;

IICDS = slave_addr;

IICSTAT = 0xf0;

//wait the interrupt to change write_ack

while(!write_ack);

//send data_addr

write_ack = 0;

IICDS = data_addr;

IICCON = 0b00101111; //recover the transmission

while(!write_ack);

//send S signal and the slave address

slave_addr |= 0b00000001;

write_ack = 0;

IICDS = slave_addr;

IICSTAT = 0b10110000;

IICCON = 0b00101111; //recover the transmission

//wait the interrupt to change write_ack

while(!write_ack);

/*

here is the most important part

we must clear IICCON[4] to inter IIC read interrupt

*/

iic_mode = 0; //read mode

read_over = 0;

IICCON = 0b00101111; //recover the transmission

delay(5);

/*

we only need to read once, but two interrupt will happen

the first interrupt happens because of receiving data from slave device

the second interrupt happens because of getting data from IICDS

*/

read_data = IICDS;

while(!read_over)

//send P signal