5)由于左边SDA_1为高,右边SDA_2为LOW, Body Diode导通; 6)SDA_1被拉低,导致NMOS VGS>0 后打开; 7)NOMO打开后,SDA_1和SDA_2相当于短在一起; 8)最终左边SDA_1被右边的SDA_2拉低变为LOW。 我们看到由于体二极管的作用,打开NMOS管,使得右边Slave输出的L=0顺利到达左边的Master SD
adap->dev.bus=&i2c_bus_type;adap->dev.type=&i2c_adapter_type;res=device_register(&adap->dev);……i2c_scan_static_board_info(adap);bus_for_each_drv(&i2c_bus_type,NULL,adap,__process_new_adapter);……} (1) device_register注册设备 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ...
i2c_cmd_handle_t cmd = i2c_cmd_link_create();i2c_master_start(cmd);i2c_master_write_byte(cmd, (device_address << 1) | I2C_MASTER_WRITE, ACK_CHECK_EN);i2c_master_write_byte(cmd, register_address, ACK_CHECK_EN);i2c_master_stop(cmd);i2c_master_cmd_begin(I2C_NUM_0, cmd, pdMS_TO...
ret = i2c_transfer(adapter,&msg,1);//num是消息的个数 return (ret == 1) ? count : ret; } static int mpu6050_read_reg_byte(struct i2c_client *client, char reg) { int ret; struct i2c_adapter *adapter = client->adapter; struct i2c_msg msg[2]; char rxbuf[1]; //先写reg寄存器...
OLED_Set_Pos(x + i, y + 1); OLED_WR_Byte(flag ? ~0x80 : 0x80, OLED_DATA); } else { OLED_Set_Pos(x + i, y + 0); OLED_WR_Byte(flag ? ~(0x01 | num[numb][i - 4]) : (0x01 | num[numb][i - 4]), OLED_DATA); ...
I2C在硬件上的接法如下(图19-1)所示,主控芯片引出两条线SCL,SDA线,在一条I2C总线上可以接很多I2C设备,我们还会放一个上拉电阻(放一个上拉电阻的原因以后我们再说)。
1. static int __device_attach(struct device *dev, bool allow_async){ bus_for_each_drv(dev->bus, NULL,&data, __device_attach_driver);} 1. i2c_scan_static_board_info //扫描硬件信息,生成与adapter总线号相同的i2c_client设备 static void i2c_scan_static_board_info(struct i2c_adapter *adapt...
delay_us(DELAY_TIEM_US);if(GPIO_ReadInputDataBit(GPIOB, I2C_AF_SDA) ==0) { GPIO_ResetBits(LED_POINT_PORT, LED_POINT); } }voiddelay_us(uint32_tus){volatileunsignedintnum;volatileunsignedintt;for(num =0; num < us; num++) { t =11;while(t !=0) { t--; } } }...
进一步,可以看下系统当前已配置了哪几个I2C总线,以标准的Linux I2C总线的命名习惯,都是以i2c-开头,以总线的序号结尾,即i2c-num。 console:/ # ls -l /dev/i2c* i2c-3 i2c-5 6 i2cdetect 检测总线上可用设备的i2c addr 如下所示,检测都1个设备,地址为0x1E ...
5 for (i = 0; i < num; i++) 6 { 7 i2c_adapter_xxx_start(); /*产生开始位*/ 8 /*是读消息*/ 9 if (msgs[i]->flags &I2C_M_RD) 10 { 11 i2c_adapter_xxx_setaddr((msg->addr << 1) | 1); /*发送从设备读地址*/ 12 i2c_adapter_xxx_wait_ack(); /*获得从设备的 ack*...