使用Arduino驅動 ADS1115 ADC採樣芯片
如圖，這是這顆ADC採樣芯片的內部結構圖，能夠看到， 從芯片引腳到芯片內部的ADC模塊，還有幾個部分： MUX，PGA， 這兩個分別叫作多路複用器、和增益放大器， MUX用來切換採樣引腳，而PGA則用來切換測量量程。oop
我參照芯片官方的數據手冊寫出了這個簡易的測試程序，只用到了最基本的IIC的通信， 使用功能也比較有限，高級一些的功能都須要使用基於IIC通信的SMBUS協議， 這個就沒有繼續深究了。測試
#include <Wire.h>
const int8_t ADS1115_address = 0x48;
enum ADS1115Conf{
AIN0_2AIN1 = 0b000, // << 12,
AIN0_2AIN3 = 0b001, // << 12,
AIN1_2AIN3 = 0b010, // << 12,
AIN2_2AIN3 = 0b011, // << 12,
AIN0_2GND = 0b100, // << 12,
AIN1_2GND = 0b101, // << 12,
AIN2_2GND = 0b110, // << 12,
AIN3_2GND = 0b111, // << 12,
FSR_6_144V = 0b000, // << 9,
FSR_4_096V = 0b001, // << 9,
FSR_2_048V = 0b010, // << 9,
FSR_1_024V = 0b011, // << 9,
FSR_0_512V = 0b100, // << 9,
FSR_0_256V = 0b101, // << 9,
CONTINU_CONV = 0, //<<8
SINGLE_SHOT = 1,
SPS_8 = 0b000, // << 5,
SPS_16 = 0b001, // << 5,
SPS_32 = 0b010, // << 5,
SPS_64 = 0b011, // << 5,
SPS_128 = 0b100, // << 5,
SPS_250 = 0b101, // << 5,
SPS_475 = 0b110, // << 5,
SPS_860 = 0b111, // << 5,
}typedef ADS1115Conf;
/**
* [ADS1115Configure description]
* @Author 葉鵬程
* @DateTime 2019-08-19T20:44:30+0800
* @discrption : 芯片初始化配置
*
* @param mux [輸入通道配置]
* @param pga [量程設置]
* @param mode [單次或持續轉換模式]
* @param dr [採樣速率設置]
*/
void ADS1115Configure(ADS1115Conf mux, ADS1115Conf pga, ADS1115Conf mode, ADS1115Conf dr){
uint16_t conf;
Wire.beginTransmission(ADS1115_address);
Wire.write(0x01); //set Address Pointer Register as conf Register
Wire.endTransmission();
/*read chip's conf register data */
Wire.requestFrom(ADS1115_address, 2);
conf = 0;
conf = Wire.read();
conf = conf<<8;
conf |= Wire.read();
/*change it*/
conf = 0x8000;
conf &= (~(0x0007<< 12)); conf |= mux << 12;
conf &= (~(0x0007<< 9 )); conf |= pga << 9;
conf &= (~(0x0007<< 8 )); conf |= mode << 8;
conf &= (~(0x0007<< 5 )); conf |= dr << 5;
// conf = 0xf483;
/* trans back*/
Wire.beginTransmission(ADS1115_address);
Wire.write(0x01); //set Address Pointer Register as conf Register
Wire.write(uint8_t(conf>>8)); //conf MSB
Wire.write(uint8_t(conf)); //conf LSB
Wire.endTransmission();
/**/
Wire.beginTransmission(ADS1115_address);
Wire.write(0x00); //set Address Pointer Register as conf Register
Wire.endTransmission();
}
/**
* [ADS1115SetChannel description]
* @Author 葉鵬程
* @DateTime 2019-08-19T20:43:57+0800
* @discrption :芯片輸入通道設置
*
* @param mux [description]
*/
void ADS1115SetChannel(ADS1115Conf mux){
uint16_t conf;
Wire.beginTransmission(ADS1115_address);
Wire.write(0x01); //set Address Pointer Register as conf Register
Wire.endTransmission();
/*read chip's conf register data */
Wire.requestFrom(ADS1115_address, 2);
conf = 0;
conf = Wire.read();
conf = conf<<8;
conf |= Wire.read();
/*change it*/
conf = conf & (~(0x0007<< 12)); conf |= mux << 12;
/* trans back*/
Wire.beginTransmission(ADS1115_address);
Wire.write(0x01); //set Address Pointer Register as conf Register
Wire.write(uint8_t(conf>>8)); //conf MSB
Wire.write(uint8_t(conf)); //conf LSB
Wire.endTransmission();
/**/
Wire.beginTransmission(ADS1115_address);
Wire.write(0x00); //set Address Pointer Register as conf Register
Wire.endTransmission();
}
int16_t ADS1115ReadResult(void){
int16_t ret;
Wire.requestFrom(ADS1115_address, 2);
ret = 0;
ret = Wire.read();
ret = ret<<8;
ret |= Wire.read();
return ret;
}
void setup() {
// put your setup code here, to run once:
Wire.begin();
Serial.begin(115200);
while (!Serial); // Leonardo: wait for serial monitor
Serial.println("Arduino Running!");
Serial.println("configing ADS1115.");
delay(200);
ADS1115Configure(AIN3_2GND, FSR_6_144V, CONTINU_CONV, SPS_250);
Serial.println("configed.");
Wire.beginTransmission(ADS1115_address);
Wire.write(0x00); //set Address Pointer Register as conv Register
Wire.write(0x00);
Wire.write(0x00);
Wire.endTransmission();
}
void loop() {
int16_t adc_result;
double v;
Serial.print("adc conversion result: ");
ADS1115SetChannel(AIN0_2GND);
delay(10);
adc_result = ADS1115ReadResult(); v = adc_result * 6.144 / 0x7fff;
Serial.print("\tA0: "); Serial.print(v); Serial.print('V');
ADS1115SetChannel(AIN1_2GND);
delay(10);
adc_result = ADS1115ReadResult(); v = adc_result * 6.144 / 0x7fff;
Serial.print("\tA1: "); Serial.print(v); Serial.print('V');
ADS1115SetChannel(AIN2_2GND);
delay(10);
adc_result = ADS1115ReadResult(); v = adc_result * 6.144 / 0x7fff;
Serial.print("\tA2: "); Serial.print(v); Serial.print('V');
ADS1115SetChannel(AIN3_2GND);
delay(10);
adc_result = ADS1115ReadResult(); v = adc_result * 6.144 / 0x7fff;
Serial.print("\tA3: "); Serial.print(v); Serial.print('V');
Serial.println();
delay(100);
// put your main code here, to run repeatedly:
}