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FDC1004学习笔记二：读写数据

news 2025/10/10 13:48:25

FDC1004采用IIC通信，不熟悉的请看这篇博客：FDC1004学习笔记一：IIC通信。

一、通信速率 10k~400k

二、读写操作

2.1写时序

先发送7为地址+“0”，然后发送8位地址，发送两个字节写入数据。

bool fdc1004_write(uint8_t  chRegAddr,uint8_t chMSB,uint8_t chLSB)
{if(!I2C_Start()){return false;}I2C_SendByte(FDC1004_COMM_ID & 0xFE);   //发送写命令I2C_WaitAck();I2C_SendByte(chRegAddr);		        //发送地址if(!I2C_WaitAck()){I2C_Stop(); return FALSE;}I2C_SendByte(chMSB);if(!I2C_WaitAck()){I2C_Stop(); return FALSE;}I2C_SendByte(chLSB);if(!I2C_WaitAck()){I2C_Stop(); return FALSE;}I2C_Stop(); //注意：因为这里要等待写完//Systick_Delay_1ms(10);//delay_nms_soft(20);I2C_delay();return TRUE;
}

2.2读时序

（1）先改变指针寄存器地址：发送7为地址+“0”，然后发送8位地址，结束；

（2）执行读取操作：发送7为地址+“1”，然后读取两字节内容，结束。

uint16_t fdc1004_read(uint8_t  chRegAddr)
{union{struct{uint8_t chLSB;uint8_t chMSB;};uint16_t    hwValue;}temp;temp.hwValue = 0;//修改地址指针寄存器if(!I2C_Start()){return false;}I2C_SendByte(FDC1004_COMM_ID & 0xFE);   //发送写命令I2C_WaitAck();I2C_SendByte(chRegAddr);		        //发送地址I2C_WaitAck();I2C_delay();I2C_Stop(); //注意：因为这里要等待写完，可以采用查询或延时方式(10ms)//Systick_Delay_1ms(10);//delay_nms_soft(20);I2C_delay();//读取数据if(!I2C_Start()){return false;}I2C_SendByte(FDC1004_COMM_ID | 0x01);   //发送读命令 if(!I2C_WaitAck()){I2C_Stop(); return false;}temp.chMSB = I2C_ReceiveByte();I2C_Ack();temp.chLSB = I2C_ReceiveByte();I2C_NoAck();I2C_Stop(); //注意：因为这里要等待写完//Systick_Delay_1ms(10);//delay_nms_soft(20);I2C_delay();return temp.hwValue;
}

三、寄存器地址及定义

//地址
#define FDC1004_COMM_ID         0xA0
#define FDC1004_DEVICE_ID       0x1004
#define FDC1004_TI_ID           0x5449//FDC1004寄存器地址
#define MEAS1_MSB_ADDR           0x00
#define MEAS1_LSB_ADDR           0x01
#define MEAS2_MSB_ADDR           0x02
#define MEAS2_LSB_ADDR           0x03
#define MEAS3_MSB_ADDR           0x04
#define MEAS3_LSB_ADDR           0x05
#define MEAS4_MSB_ADDR           0x06
#define MEAS4_LSB_ADDR           0x07
#define CONF_MEAS1_ADDR          0x08
#define CONF_MEAS2_ADDR          0x09
#define CONF_MEAS3_ADDR          0x0A
#define CONF_MEAS4_ADDR          0x0B
#define FDC_CONF_ADDR            0x0C
#define OFFSET_CAL_CIN1_ADDR     0x0D
#define OFFSET_CAL_CIN2_ADDR     0x0E
#define OFFSET_CAL_CIN3_ADDR     0x0F
#define OFFSET_CAL_CIN4_ADDR     0x10
#define GAIN_CAL_CIN1_ADDR       0x11
#define GAIN_CAL_CIN2_ADDR       0x12
#define GAIN_CAL_CIN3_ADDR       0x13
#define GAIN_CAL_CIN4_ADDR       0x14
#define TI_ID_ADDR               0xFE
#define DEVICE_ID_ADDR           0xFF//寄存器
typedef union{struct{uint16_t    hwMeasLsb;uint16_t    hwMeasMsb;};uint32_t    wMeasValue;
}measn_t;     //电容值typedef union{struct{uint16_t                :5;uint16_t    hwCapDac    :5;uint16_t    hwCHB       :3;uint16_t    hwCHA       :3;};uint16_t    hwConfMeasValue;
}conf_measn_t;     //通道配置typedef union{struct{uint16_t    hwDone4     :1;uint16_t    hwDone3     :1;uint16_t    hwDone2     :1;uint16_t    hwDone1     :1;uint16_t    hwMeas4     :1;uint16_t    hwMeas3     :1;uint16_t    hwMeas2     :1;uint16_t    hwMeas1     :1;uint16_t    hwRepeat    :1;uint16_t                :1;uint16_t    hwRate      :2;uint16_t                :3;uint16_t    hwRst       :1;};uint16_t    hwFdcConfValue;
}fdc_conf_t;      //数字部分配置typedef union{struct{uint16_t    hwDecimalPart     :11;uint16_t    hwInteherPart     :5;};uint16_t    hwOffsetCalValue;
}offset_cal_t;    //偏移值typedef union{struct{uint16_t    hwDecimalPart     :14;uint16_t    hwInteherPart     :2;};uint16_t    hwOffsetCalValue;
}gain_cal_t;      //增益typedef enum __select_channel_t{SELECT_CIN1 = 0x01,SELECT_CIN2 = 0x02,SELECT_CIN3 = 0x03,SELECT_CIN4 = 0x04,
}select_channel_t;//配置值
//通道配置CHA
typedef enum __cha_t{CHA_CIN1 = 0x00,CHA_CIN2 = 0x01,CHA_CIN3 = 0x02,CHA_CIN4 = 0x03,
}cha_t;//通道配置CHB
typedef enum __chb_t{CHB_CIN1      = 0x00,CHB_CIN2      = 0x01,CHB_CIN3      = 0x02,CHB_CIN4      = 0x03,CHB_CAPDAC_EN = 0x04,CHB_CAPDAC_DIS= 0x07,
}chb_t;//通道配置Rate
typedef enum __rate_t{RATE_100 = 0x01,RATE_200 = 0x02,RATE_400 = 0x03,
}rate_t;

四、电容值读取

两个寄存器32位，低8位无效；剩余24位，其中符号位1位，整数位4位，小数位19位。

int32_t fdc1004_read_cap(uint8_t  chRegAddr)
{union{struct{uint16_t hwLSB;uint16_t hwMSB;};int32_t      iValue;}temp;temp.iValue = 0;temp.hwMSB = fdc1004_read(chRegAddr);temp.hwLSB = fdc1004_read(chRegAddr+0x01);return temp.iValue;
}float fdc1004_read_cap_value(uint8_t  chRegAddr)
{union{struct{uint16_t hwLSB;uint16_t hwMSB;};int32_t      iValue;}temp;float fTempValue = 0;temp.iValue = 0;temp.hwMSB = fdc1004_read(chRegAddr);temp.hwLSB = fdc1004_read(chRegAddr+0x01);fTempValue = (temp.iValue >> 8);fTempValue = fTempValue/524288.0;return (fTempValue);
}

运行效果：