一、概述
该博客介绍使用软件模拟 SPI驱动16位 ADTM7705(兼容AD7705）
TM7705 使用SPI串行通信协议，使用十分方便快捷．并且兼容 2.7~3.3V 或 4.75~5.25V 单电源。可以直接使用单片机引脚进行供电． TM7705 是用于智能系统、微控制器系统和基于 DSP 系统的理想产品。其串行接口可配置为三线接口。增益值、信号极性以及更新速率的选择可用串行输入口由软件来配置。该器件还包括自校准和系统校准选项,以消除器件本身或系统的增益和偏移误差。TM7705 采用 16 脚塑料双列直插(DIP)和 16 脚宽体(0.3 英寸)SOIC 封装和 16 脚 TSSOP 封装。
二、特点
TM7705:2 个全差分输入通道的 ADC
16 位无丢失代码
0.003%非线性
可编程增益前端
增益:1~128
三线串行接口
有对模拟输入缓冲的能力
2.7~3.3V 或 4.75~5.25V 工作电压
3V 电压时,最大功耗为 1mW
等待电流的最大值为 8μA
16 脚 DIP、SOIC 和 TSSOP 封装三．引脚排列
四．引脚功能
五.代码讲解
esp32WROOM 32D 驱动AD 7705代码
AD7705.h头文件
#include "driver/gpio.h"
#ifndef __AD7705_H__
#define __AD7705_H__
#define ADC_DI 23//DIN引脚
#define ADC_DO1 25//DOUT引脚
#define ADC_CLK 19//SCK引脚
#define ADC_RESET 18//RST引脚
#define ADC1_CS 22//CS引脚
#define ADC1_DRDY1 21//DRDY引脚
#define ADC_CLK0 gpio_set_level(ADC_CLK, 0)//CLK引脚设置为低电平
#define ADC_CLK1 gpio_set_level(ADC_CLK, 1)//CLK引脚设置为高电平
#define ADC_RESET0 gpio_set_level(ADC_RESET, 0)//RST引脚设置为低电平
#define ADC_RESET1 gpio_set_level(ADC_RESET, 1)//RST引脚设置为高电平
#define ADC_DI0 gpio_set_level(ADC_DI, 0)//DIN引脚设置为低电平
#define ADC_DI1 gpio_set_level(ADC_DI, 1)//DIN引脚设置为高电平
#define ADC1_CS0 gpio_set_level(ADC1_CS, 0)//CS引脚设置为低电平
#define ADC1_CS1 gpio_set_level(ADC1_CS, 1)//CS引脚设置为高电平
#define ADC_DO gpio_get_level(ADC_DO1)//获取DOUT引脚电平
#define ADC1_DRDY gpio_get_level(ADC1_DRDY1)//获取DRDY引脚电平
//Operation modes
#define ADC_NORMAL 0x00
#define ADC_SELF 0x40
#define ADC_ZERO_SCALE 0x80
#define ADC_FULL_SCALE 0xc0
//Gain settings
#define ADC_GAIN_1 0x00
#define ADC_GAIN_2 0x08
#define ADC_GAIN_4 0x10
#define ADC_GAIN_8 0x18
#define ADC_GAIN_16 0x20
#define ADC_GAIN_32 0x28
#define ADC_GAIN_64 0x30
#define ADC_GAIN_128 0x38
//Polar operations
#define ADC_BIPOLAR 0x00
#define ADC_UNIPOLAR 0x04
//update rates
#define ADC_50 0x04
#define ADC_60 0x05
#define ADC_250 0x06
#define ADC_500 0x07
extern void TM7705_CaliSelf(unsigned char ch);
extern void adc_rest();
extern void adc1_init(unsigned char calmode, unsigned char gainsetting, unsigned char operation, unsigned char rate);
extern unsigned int adc1_read_value(unsigned char ch);
#endifAD7705.C文件
#include "AD7705.h"
#include "driver/gpio.h"
enum
{
REG_COMM = 0x00, //通信寄存器
REG_SETUP = 0x10,//设置寄存器
REG_CLOCK = 0x20, //时钟寄存器
REG_DATA = 0x30, //数据寄存器
REG_ZERO_CH1 = 0x60, //CH1偏移寄存器
REG_FULL_CH1 = 0x70,//CH1满量程寄存器
REG_ZERO_CH2 = 0x61, //CH2偏移寄存器
REG_FULL_CH2 = 0x71, //CH２满量程寄存器
WRITE = 0x00, //写操作
READ = 0x08, //读操作
CH_1 = 0,
CH_2 = 1,
CH_3 = 2,
CH_4 = 3
};
enum
{
CLKDIS_0 = 0x00, //时钟输出使能
CLKDIS_1 = 0x10, //时钟禁止
CLK_4_9152M = 0x08,//4.9152MHZ晶振
CLK_2_4576M = 0x00,//2.456MHZ晶振
CLK_1M = 0x04,
CLK_2M = 0x0C,
FS_50HZ = 0x00,
FS_60HZ = 0x01,
FS_250HZ = 0x02,
FS_500HZ = 0x04,
ZERO_0 = 0x00,
ZERO_1 = 0x80
};
enum
{
MD_NORMAL = (0 << 6), //正常模式
MD_CAL_SELF = (1 << 6), //自校准模式
MD_CAL_ZERO = (2 << 6), //标准零刻度模式
MD_CAL_FULL = (3 << 6),//标准满刻度模式
GAIN_1 = (0 << 3),//增益
GAIN_2 = (1 << 3), //增益
GAIN_4 = (2 << 3),//增益
GAIN_8 = (3 << 3),//增益
GAIN_16 = (4 << 3), //增益
GAIN_32 = (5 << 3), //增益
GAIN_64 = (6 << 3),//增益
GAIN_128 = (7 << 3),//增益
BIPOLAR = (0 << 2), //双极性输入
UNIPOLAR = (1 << 2), //单极性输入
BUF_NO = (0 << 1),
BUF_EN = (1 << 1),
FSYNC_0 = 0,
FSYNC_1 = 1
};
/*通道１和通道２ 的增益，输入缓冲，极性设置*/
#define _CH1_GAIN_BIPOLAR_BUF (GAIN_1|UNIPOLAR|BUF_EN)
#define _CH2_GAIN_BIPOLAR_BUF (GAIN_1|UNIPOLAR|BUF_EN)
void adc_delay(unsigned char NUM) //延时函数
{
for(;NUM>0;NUM--);
}
void write_adc_byte(unsigned char chr)//写字节函数
{
unsigned char i;
for(i=0;i<8;i++)//循环写八次
{
if (chr & 0x80)//位与操作，写出数据
{
ADC_DI1;//SPI 数据MOSI 接口 按位输出
}
else
{
ADC_DI0;//SPI 数据MOSI 接口
}
ADC_CLK0;//时钟信号
chr=chr<<1;//右移一位数据，循环按位写出数据
ADC_CLK1;
}
//ADC_CLK1;
}
unsigned int read_adc_word()//读数据函数
{
unsigned char i;
unsigned int coder = 0;
for(i=0;i<16;i++)//16位数据，循环读入两个字节
{
ADC_CLK0;//时钟信号
adc_delay(1);
coder = coder<<1;
if(ADC_DO)coder+=1; //检测引脚电平，读入数据
ADC_CLK1;
}
ADC_CLK1;
return(coder);
}
void adc_rest()//AD 7705复位函数
{
unsigned char i,j;
ADC_DI1;
ADC_CLK1;
ADC1_CS1;
ADC_RESET1;
for(i=200;i>0;i--)
for(j=200;j>0;j--);
ADC_RESET0;
for(i=400;i>0;i--)
for(j=200;j>0;j--);
ADC_RESET1;
for(i=200;i>0;i--)
for(j=200;j>0;j--);
}
void TM7705_CaliSelf(unsigned char ch)//自校准函数
{
if(ch==1){
ADC1_CS0;
write_adc_byte(REG_SETUP|WRITE|CH_1);
ADC1_CS1;
adc_delay(10);
ADC1_CS0;
write_adc_byte(MD_CAL_SELF|_CH1_GAIN_BIPOLAR_BUF|FSYNC_0);
ADC1_CS1;
adc_delay(10);
ADC1_CS0;
while (ADC1_DRDY);
ADC1_CS1;
}
else if(ch==2){
ADC1_CS0;
write_adc_byte(REG_SETUP|WRITE|CH_2);
ADC1_CS1;
adc_delay(10);
ADC1_CS0;
write_adc_byte(MD_CAL_SELF|_CH2_GAIN_BIPOLAR_BUF|FSYNC_0);
ADC1_CS1;
adc_delay(10);
ADC1_CS0;
while (ADC1_DRDY);
ADC1_CS1;
}
}
void adc1_init(unsigned char calmode, unsigned char gainsetting, unsigned char operation, unsigned char rate)
{
ADC1_CS0;
write_adc_byte(0xFF);
write_adc_byte(0xFF);
write_adc_byte(0xFF);
write_adc_byte(0xFF);
ADC1_CS1;
adc_delay(100);
ADC1_CS0;
//write_adc_byte( 0x20 );//
write_adc_byte( REG_CLOCK|WRITE|CH_1 );//
ADC1_CS1;
adc_delay(100);
ADC1_CS0;
write_adc_byte( CLKDIS_0|CLK_4_9152M|FS_50HZ );//
ADC1_CS1;
TM7705_CaliSelf(1);
TM7705_CaliSelf(2);
adc_delay(100);
}
unsigned int adc1_read_value(unsigned char ch)
{
unsigned int value;
if(!ADC1_DRDY)
{
ADC1_CS0;
if(ch == 1)
write_adc_byte(0x38);//
else if(ch == 2)
write_adc_byte(0x39);//
else {ADC1_CS1;return 0;}
ADC1_CS1;
adc_delay(1);
ADC1_CS0;
value = read_adc_word();
ADC1_CS1;
return value;
}
else
{
return 0;
}
}main.c文件
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "driver/gpio.h"
#include "AD7705.h"
void delay(unsigned int NUM)
{
unsigned int i;
unsigned char j;
for(i=NUM;i>0;i--)
for(j=200;j>0;j--);
}
void app_main(void)
{ int volt1,volt2;
unsigned char i,stat=0x03;
unsigned int temp1,temp2,ADcode1,ADcode2;
//Initialize non-SPI GPIOs
gpio_set_direction(ADC_CLK, GPIO_MODE_OUTPUT);
gpio_set_direction(ADC_RESET, GPIO_MODE_OUTPUT);
gpio_set_direction(ADC1_CS, GPIO_MODE_OUTPUT);
gpio_set_direction(ADC_DI, GPIO_MODE_OUTPUT);
gpio_set_pull_mode(ADC_DO1,GPIO_PULLUP_ENABLE);
gpio_set_direction(ADC_DO1, GPIO_MODE_INPUT);
gpio_set_direction(ADC1_DRDY1, GPIO_MODE_INPUT);
adc_rest();
adc1_init(ADC_SELF,ADC_GAIN_128,ADC_BIPOLAR,ADC_50);
TM7705_CaliSelf(1);
temp1 = adc1_read_value(1);
TM7705_CaliSelf(2);
temp2 = adc1_read_value(2);
while(1){
printf("初始化代码\n");
vTaskDelay(500/ portTICK_PERIOD_MS);
temp1 = adc1_read_value(1);
volt1=((int)temp1*5000)/65536;
printf("channel1: %d V:%d\n",temp1,volt1);
vTaskDelay(500/ portTICK_PERIOD_MS);
temp2 = adc1_read_value(2);
volt2=((int)temp2*5000)/65536;
printf("channel2: %d V:%d\n",temp2,volt2);
}
}
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