新聞中心

        EEPW首頁 > 嵌入式系統(tǒng) > 設(shè)計(jì)應(yīng)用 > 測試基于linux-2.6.27的9G9260開發(fā)板I2C驅(qū)動(dòng)

        測試基于linux-2.6.27的9G9260開發(fā)板I2C驅(qū)動(dòng)

        作者: 時(shí)間:2012-09-11 來源:網(wǎng)絡(luò) 收藏

        1,找到drivers/i2c/busses/i2c-at91.c文件

        本文引用地址:http://www.104case.com/article/148411.htm

        root@yuanxh-desktop:/home/yuanxh/sam9260/-9g9260# vi drivers/i2c/busses/Makefile

        在第28行看到:

        obj-$(CONFIG__AT91) += i2c-at91.o

        2, 找到drivers/i2c/busses/Kconfig文件

        root@yuanxh-desktop:/home/yuanxh/sam9260/-9g9260# vi drivers/i2c/busses/Kconfig

        在第259行看到:

        config _AT91

        tristate Atmel AT91 Two-Wire interface (TWI)

        depends on ARCH_AT91 EXPERIMENTAL BROKEN

        help

        This supports the use of the I2C interface on Atmel AT91

        processors.

        This driver is BROKEN because the controller which it uses

        will easily trigger RX overrun and TX underrun errors. Using

        low I2C clock rates may partially work around those issues

        on some systems. Another serious problem is that there is no

        documented way to issue repeated START conditions, as needed

        to support combined I2C messages. Use the i2c-gpio driver

        unless your system can cope with those limitations.

        說明AT91 I2C標(biāo)準(zhǔn)不穩(wěn)定,需要用GPIO模擬!!!

        3,編譯配置內(nèi)核

        root@yuanxh-desktop:/home/yuanxh/sam9260/-9g9260# make menuconfig

        進(jìn)入配置菜單添加到內(nèi)核:

        Device Drivers --->

        *> I2C support --->

        *> I2C device interface

        I2C Hardware Bus support --->

        *> GPIO-based bitbanging I2C

        4, 編譯內(nèi)核生成

        root@yuanxh-desktop:/home/yuanxh/sam9260/linux-2.6.27-9g9260# make

        5, 查看內(nèi)核啟動(dòng)信息

        i2c /dev entries driver

        i2c-gpio i2c-gpio: using pins 55 (SDA) and 56 (SCL)

        6,查看內(nèi)核系統(tǒng)信息

        # cat /proc/devices

        會(huì)看到

        Character devices:

        ...

        89 i2c

        ...

        # cat /sys/devices/platform/i2c-gpio/i2c-adapter:i2c-0/name

        i2c-gpio-1

        7,建立設(shè)備結(jié)點(diǎn)

        mknod /dev/i2c-0 c 89 0

        8,編譯代碼

        root@yuanxh-desktop:/home/yuanxh/sam9260/i2ctest-1.0-9g9260# arm-linux-gcc -o i2ctest i2ctest.c

        root@yuanxh-desktop:/home/yuanxh/sam9260/i2ctest-1.0-9g9260# cp i2ctest /nfsboot/rootfs/app

        9,運(yùn)行代碼

        # /app/i2ctest

        I2C Test version 1.0-9g9260 (yuanxihua@21cn.com) Buile on Jan 5 2009 00:54:45

        buf[0x00] = 0x46

        ...

        附件:

        //i2ctest.c

        #include

        #include

        #include

        #include

        #include

        #include

        #define CHIP_ADDR 0x50 //24C64

        #define PAGE_SIZE 32

        #define I2C_DEV /dev/i2c-0

        static int read_eeprom(int fd,char buff[],int addr,int count)

        {

        int res;

        if (write(fd,addr,1)!=1)

        {

        printf(Can't write %s's addr %dn,I2C_DEV,addr);

        return -1;

        }

        res = read(fd,buff,count);

        printf(read %d bytes at 0x%02xnr,res,addr);

        return res;

        }

        static int write_eeprom(int fd,char buff[],int addr,int count)

        {

        int res;

        int i;

        static char sendbuffer[PAGE_SIZE+1];

        memcpy(sendbuffer+1,buff,count);

        sendbuffer[0]=addr;

        res = write(fd,addr,count+1);

        printf(write %d bytes at 0x%02xnr,res,addr);

        return res;

        }

        int main(void)

        {

        int fd,i,res;

        unsigned char buf[PAGE_SIZE];

        printf(I2C Test version 1.0-9g9260 (yuanxihua@21cn.com) Buile on %s %snr,__DATE__,__TIME__);

        fd=open(I2C_DEV,O_RDWR);

        if(fd0)

        {

        printf(Can't Open %s !!!nr,I2C_DEV);

        return -1;

        }

        res = ioctl(fd,I2C_TENBIT,0);

        res = ioctl(fd,I2C_SLAVE,CHIP_ADDR);

        for(i=0;i

        {

        // write_eeprom(fd,buf,i,1);

        }

        for(i=0;i

        {

        read_eeprom (fd,buf+i,i,1);

        printf(buf[0x%02x] = 0x%02xnr,i,buf[i]);

        }

        close(fd);

        return 0;

        }

        linux操作系統(tǒng)文章專題:linux操作系統(tǒng)詳解(linux不再難懂)


        評論


        相關(guān)推薦

        技術(shù)專區(qū)

        關(guān)閉
        主站蜘蛛池模板: 石景山区| 台东市| 板桥市| 沐川县| 台南县| 岢岚县| 交口县| 宣威市| 遵化市| 中山市| 深泽县| 安阳市| 渝北区| 攀枝花市| 五原县| 广安市| 邵阳市| 内乡县| 夏邑县| 宿松县| 青神县| 田林县| 马尔康县| 神农架林区| 天祝| 扶风县| 都江堰市| 沁阳市| 侯马市| 柳州市| 舞阳县| 满洲里市| 格尔木市| 白城市| 巫山县| 囊谦县| 怀安县| 临澧县| 荥经县| 昌黎县| 唐海县|