LTC2944库仑计（电量计）芯片应用笔记（Arduino，ESP32）_钛酸锂库仑计

0Fh寄存器的最低4位一直都保持是0，因为ADC只有12bit。所以当寄存器读出FFF0h的时候，代表电流测量的正满量程64mV；当寄存器读出值为0000h时，代表电流测量值为负满量程-64mV。那么，假设电流的寄存器读出值为Ic，实际测量值的计算方法就是：计算结果为正的话，表示在充电；为负的话表示在放电。

2401_84010744

2791人浏览 · 2024-05-13 16:05:31

2401_84010744 · 2024-05-13 16:05:31 发布

0Fh寄存器的最低4位一直都保持是0，因为ADC只有12bit。所以当寄存器读出FFF0h的时候，代表电流测量的正满量程64mV；当寄存器读出值为0000h时，代表电流测量值为负满量程-64mV。

那么，假设电流的寄存器读出值为Ic，实际测量值的计算方法就是：

I=(64mV/Rsense)*((Ic-32767)/32767)

计算结果为正的话，表示在充电；为负的话表示在放电。

（3）电量mAH

电量计数器（ACR）也是16bit，每一bit代表的电量取决于M（prescaler）的值和Rsense的值。

公式如下：

通过读取ACR的值，乘以Qlsb即可得出当前读数。

在默认值M=4096和Rsense=50mΩ的情况下，计数器加或减1所代表电量变化0.34mAH。

这个0.34怎么来的我也不知道，手册上就是这么说的。

单位为mAH，要换算成库伦自己算。

（4）温度

温度ADC有效位为11位，最低5位始终保持为0，通过下面公式直接算出实际温度：

单位K，要把结果换算成℃的话自己算。

5.芯片工作模式

（1）shutdown模式

控制寄存器bit0设置为1可以将芯片设置为关闭模式，此时整个芯片模拟部分，包括电量计数器、ADC全部停止工作，但是I2C部分保持在工作，芯片耗电量降到最低约15微安。电量计数器ACR在这种模式下不再变化，无法进行电量计量。

（2）ADC模块的四种模式

控制寄存器bit7和bit6组合ADC成4中工作模式：

11：全自动模式，芯片持续进行ADC转换，约30ms完成一次；

10：扫描模式，每10秒进行一次ADC转换，其余时间休眠；

01：人工模式，人为发命令启动才进行一次ADC转换，然后休眠；

00：休眠模式

ADC转换次数越多，耗电越厉害，全自动模式下耗电约1mA，详见手册。

三、驱动程序

1.驱动源码

芯片了解完成终于要动手编写驱动了。Linear（已被ADI收购）专门为该芯片提供了一份驱动程序，地址:LTC2944 数据手册和产品信息 | 亚德诺（ADI）半导体

但是这个程序是Linduino平台的，这个东东咱也没用过，但是源码还是可以参考下的。

下面我们把链接上的LTC2944.h和LTC2944.cpp下载下来进行改造。

详细的改造过程省略了，对改造过程感兴趣的可以对比下下面代码和原来的代码之间的差异。

主要改造4个函数：

int8_t LTC2944_write(uint8_t i2c_address, uint8_t adc_command, uint8_t code);
int8_t LTC2944_write_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t code);
int8_t LTC2944_read(uint8_t i2c_address, uint8_t adc_command, uint8_t *adc_code);
int8_t LTC2944_read_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t *adc_code)

这4个函数是对总线的操作，改造内容是把I2C的操作方法改成Wire方法，其他函数基本都是内部计算函数，不用改造。其他的改造内容都是为了方便使用而改造的，包括增加一些操作函数。

直接给出改造后的源码如下。

LTC2944.h

#ifndef LTC2944_h
#define LTC2944_h
 
#include "Arduino.h"
#include "Wire.h"


#define I2C_ADDRESS_LTC2944 0x64
//#define I2C_ADDR_LTC2944 144

//Registers
#define LTC2944_STATUS_REG                          0x00
#define LTC2944_CONTROL_REG                         0x01
#define LTC2944_ACCUM_CHARGE_MSB_REG                0x02
#define LTC2944_ACCUM_CHARGE_LSB_REG                0x03
#define LTC2944_CHARGE_THRESH_HIGH_MSB_REG          0x04
#define LTC2944_CHARGE_THRESH_HIGH_LSB_REG          0x05
#define LTC2944_CHARGE_THRESH_LOW_MSB_REG           0x06
#define LTC2944_CHARGE_THRESH_LOW_LSB_REG           0x07
#define LTC2944_VOLTAGE_MSB_REG                     0x08
#define LTC2944_VOLTAGE_LSB_REG                     0x09
#define LTC2944_VOLTAGE_THRESH_HIGH_MSB_REG         0x0A
#define LTC2944_VOLTAGE_THRESH_HIGH_LSB_REG         0x0B
#define LTC2944_VOLTAGE_THRESH_LOW_MSB_REG          0x0C
#define LTC2944_VOLTAGE_THRESH_LOW_LSB_REG          0x0D
#define LTC2944_CURRENT_MSB_REG                     0x0E
#define LTC2944_CURRENT_LSB_REG                     0x0F
#define LTC2944_CURRENT_THRESH_HIGH_MSB_REG         0x10
#define LTC2944_CURRENT_THRESH_HIGH_LSB_REG         0x11
#define LTC2944_CURRENT_THRESH_LOW_MSB_REG          0x12
#define LTC2944_CURRENT_THRESH_LOW_LSB_REG          0x13
#define LTC2944_TEMPERATURE_MSB_REG                 0x14
#define LTC2944_TEMPERATURE_LSB_REG                 0x15
#define LTC2944_TEMPERATURE_THRESH_HIGH_REG         0x16
#define LTC2944_TEMPERATURE_THRESH_LOW_REG          0x17

// Command Codes
#define LTC2944_AUTOMATIC_MODE                      0xC0
#define LTC2944_SCAN_MODE                           0x80
#define LTC2944_MANUAL_MODE                         0x40
#define LTC2944_SLEEP_MODE                          0x00
#define LTC2944_PRESCALAR_M_1                       0x00
#define LTC2944_PRESCALAR_M_4                       0x08
#define LTC2944_PRESCALAR_M_16                      0x10
#define LTC2944_PRESCALAR_M_64                      0x18
#define LTC2944_PRESCALAR_M_256                     0x20
#define LTC2944_PRESCALAR_M_1024                    0x28
#define LTC2944_PRESCALAR_M_4096                    0x30
#define LTC2944_PRESCALAR_M_4096_2                  0x31
#define LTC2944_ALERT_MODE                          0x04
#define LTC2944_CHARGE_COMPLETE_MODE                0x02
#define LTC2944_DISABLE_ALCC_PIN                    0x00
#define LTC2944_SHUTDOWN_MODE                       0x01
#define LTC2944_SHUTDOWN_MODE_UNDO                  0x00




class I2CLTC2944
{
  public:
    I2CLTC2944(TwoWire * ptrI2CBus)
    {
      _ptrI2CBus=ptrI2CBus;
    }

    int8_t  LTC2944_write(uint8_t i2c_address, uint8_t adc_command, uint8_t code);
    int8_t  LTC2944_write_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t code);
    int8_t  LTC2944_read(uint8_t i2c_address, uint8_t adc_command, uint8_t *adc_code);
    int8_t  LTC2944_read_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t *adc_code);
    float   LTC2944_code_to_coulombs(uint16_t adc_code, float resistor, uint16_t prescalar);
    float   LTC2944_code_to_mAh(uint16_t adc_code, float resistor, uint16_t prescalar );
    float   LTC2944_code_to_voltage(uint16_t adc_code);
    float   LTC2944_code_to_current(uint16_t adc_code, float resistor);
    float   LTC2944_code_to_kelvin_temperature(uint16_t adc_code);
    float   LTC2944_code_to_celcius_temperature(uint16_t adc_code);
    int8_t  LTC2944_register_set_clear_bits(uint8_t i2c_address, uint8_t register_address, uint8_t bits_to_set, uint8_t bits_to_clear);  
    int8_t  LTC2944_set_mode(uint8_t i2c_address,uint8_t mode);
    int8_t  LTC2944_set_prescalar(uint8_t i2c_address,uint16_t prescalarVal);
    int8_t  LTC2944_set_ALCC(uint8_t i2c_address,uint8_t ALCCMode);
    int8_t  LTC2944_set_shutdown(uint8_t i2c_address,uint8_t shutdown);
    int8_t  LTC2944_set_ACR_full(uint8_t i2c_address);

  private:
    TwoWire * _ptrI2CBus;
};
 
#endif

LTC2944.cpp

#include "Arduino.h"
#include "LTC2944.h"



//Conversion Constants
const float LTC2944_CHARGE_lsb = 0.34E-3;
const float LTC2944_VOLTAGE_lsb = 1.068E-3;
const float LTC2944_CURRENT_lsb = 29.3E-6;
const float LTC2944_TEMPERATURE_lsb = 0.25;
const float LTC2944_FULLSCALE_VOLTAGE = 70;
const float LTC2944_FULLSCALE_CURRENT = 60E-3;
const float LTC2944_FULLSCALE_TEMPERATURE = 510;

const float resistor = .020;                               //!< resistor value 




int8_t I2CLTC2944::LTC2944_write(uint8_t i2c_address, uint8_t adc_command, uint8_t code)
{
  // Write an 8-bit code to the LTC2944.
  // The function returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
  int32_t ack;
  //ack = i2c_write_byte_data(i2c_address, adc_command, code);
  _ptrI2CBus->beginTransmission(i2c_address);
  _ptrI2CBus->write(adc_command);
  _ptrI2CBus->write(code);
  ack=_ptrI2CBus->endTransmission(true);
  return(ack);
}


int8_t I2CLTC2944::LTC2944_write_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t code)
{
  // Write a 16-bit code to the LTC2944.
  // The function returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
  int8_t ack;
  //ack = i2c_write_word_data(i2c_address, adc_command, code);
  _ptrI2CBus->beginTransmission(i2c_address);
  _ptrI2CBus->write(adc_command);
  _ptrI2CBus->write(code);
  ack=_ptrI2CBus->endTransmission(true);  
  return(ack);
}



int8_t I2CLTC2944::LTC2944_read(uint8_t i2c_address, uint8_t adc_command, uint8_t *adc_code)
{
  // Reads an 8-bit adc_code from LTC2944
  // The function returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
  int32_t ack;
  //ack = i2c_read_byte_data(i2c_address, adc_command, adc_code);
  _ptrI2CBus->flush();
  _ptrI2CBus->beginTransmission(i2c_address);
  _ptrI2CBus->write(adc_command);
  ack=_ptrI2CBus->endTransmission(false);    
  uint8_t bytesReceived=0;
  bytesReceived=_ptrI2CBus->requestFrom(i2c_address,1);
  if(bytesReceived==1)
  {
    *adc_code=_ptrI2CBus->read();
  }
  else
  {
    //Serial.println("LTC2944_read reply error!");
  }
  return(ack);
}

int8_t I2CLTC2944::LTC2944_read_16_bits(uint8_t i2c_address, uint8_t adc_command, uint16_t *adc_code)
{
  // Reads a 16-bit adc_code from LTC2944
  // The function returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
  int32_t ack;
  //ack = i2c_read_word_data(i2c_address, adc_command, adc_code);
  _ptrI2CBus->flush();
  _ptrI2CBus->beginTransmission(i2c_address);
  _ptrI2CBus->write(adc_command);
  ack=_ptrI2CBus->endTransmission(false);    
  uint8_t bytesReceived=0;
  uint8_t temp[2];
  bytesReceived=_ptrI2CBus->requestFrom(i2c_address,2);
  if(bytesReceived==2)
  {
    temp[0]=_ptrI2CBus->read();
    //Serial.print("MSB=");Serial.println(temp[0]);
    temp[1]=_ptrI2CBus->read();
    //Serial.print("LSB=");Serial.println(temp[1]);
    //_ptrI2CBus->readBytes(temp, bytesReceived);
    *adc_code=temp[0]*256+temp[1];
  }
  else
  {
    //Serial.print("read NOT 2 bytes! recv bytes=");Serial.println(bytesReceived);
  }
  return(ack);  
}


float I2CLTC2944::LTC2944_code_to_coulombs(uint16_t adc_code, float resistor, uint16_t prescalar)
{
  // The function converts the 16-bit RAW adc_code to Coulombs
  float coulomb_charge;
  coulomb_charge =  1000*(float)(adc_code*LTC2944_CHARGE_lsb*prescalar*50E-3)/(resistor*4096);
  coulomb_charge = coulomb_charge*3.6f;
  return(coulomb_charge);
}

float I2CLTC2944::LTC2944_code_to_mAh(uint16_t adc_code, float resistor, uint16_t prescalar )
{
  // The function converts the 16-bit RAW adc_code to mAh
  float mAh_charge;
  mAh_charge = 1000*(float)(adc_code*LTC2944_CHARGE_lsb*prescalar*50E-3)/(resistor*4096);
  return(mAh_charge);
}

float I2CLTC2944::LTC2944_code_to_voltage(uint16_t adc_code)
{
  // The function converts the 16-bit RAW adc_code to Volts
  float voltage;
  voltage = ((float)adc_code/(65535))*LTC2944_FULLSCALE_VOLTAGE;
  return(voltage);
}

float I2CLTC2944::LTC2944_code_to_current(uint16_t adc_code, float resistor)
{
  // The function converts the 16-bit RAW adc_code to Amperes
  float current;
  current = (((float)adc_code-32767)/(32767))*((float)(LTC2944_FULLSCALE_CURRENT)/resistor);
  return(current);
}

float I2CLTC2944::LTC2944_code_to_kelvin_temperature(uint16_t adc_code)
{
  // The function converts the 16-bit RAW adc_code to Kelvin
  float temperature;
  temperature = adc_code*((float)(LTC2944_FULLSCALE_TEMPERATURE)/65535);
  return(temperature);
}

float I2CLTC2944::LTC2944_code_to_celcius_temperature(uint16_t adc_code)
{
  // The function converts the 16-bit RAW adc_code to Celcius
  float temperature;
  temperature = adc_code*((float)(LTC2944_FULLSCALE_TEMPERATURE)/65535) - 273.15;
  return(temperature);
}


int8_t I2CLTC2944::LTC2944_register_set_clear_bits(uint8_t i2c_address, uint8_t register_address, uint8_t bits_to_set, uint8_t bits_to_clear)
{
  // Used to set and clear bits in a control register.  bits_to_set will be bitwise OR'd with the register.
  // bits_to_clear will be inverted and bitwise AND'd with the register so that every location with a 1 will result in a 0 in the register.  
  uint8_t register_data;
  int8_t ack = 0;

  ack |= LTC2944_read(i2c_address, register_address, &register_data);
  register_data = register_data & (~bits_to_clear);
  register_data = register_data | bits_to_set;
  ack |= LTC2944_write(i2c_address, register_address, register_data);
  return(ack);
}


int8_t I2CLTC2944::LTC2944_set_mode(uint8_t i2c_address,uint8_t mode)
{
  //"mode" must be one of the defined symbols:
  //    LTC2944_AUTOMATIC_MODE,LTC2944_SCAN_MODE,LTC2944_MANUAL_MODE,LTC2944_SLEEP_MODE
  uint8_t curCode;
  uint8_t setCode;
  int8_t ack = 0;
  ack |= LTC2944_read(i2c_address, LTC2944_CONTROL_REG, &curCode);
  setCode = mode | (curCode & B00111111);//B[7:6]
  ack |= LTC2944_write(i2c_address, LTC2944_CONTROL_REG, setCode);
  return(ack);
}

int8_t I2CLTC2944::LTC2944_set_prescalar(uint8_t i2c_address,uint16_t prescalarVal)
{
  //"prescalarVal" must be one of the defined symbols:
  //    LTC2944_PRESCALAR_M_1,LTC2944_PRESCALAR_M_4,LTC2944_PRESCALAR_M_16
  //    LTC2944_PRESCALAR_M_64,LTC2944_PRESCALAR_M_256,LTC2944_PRESCALAR_M_1024
  //    LTC2944_PRESCALAR_M_4096
  uint8_t curCode;
  uint8_t setCode;
  int8_t ack = 0;
  LTC2944_read(i2c_address,LTC2944_CONTROL_REG,&curCode);
  setCode = prescalarVal | (curCode & B11000111);//B[5:3]
  ack |= LTC2944_write(i2c_address, LTC2944_CONTROL_REG, setCode);
  return(ack);
}

int8_t I2CLTC2944::LTC2944_set_ALCC(uint8_t i2c_address,uint8_t ALCCMode)
{
  //"ALCCMode"  must be one of the defined symbols:
  //    LTC2944_ALERT_MODE,LTC2944_CHARGE_COMPLETE_MODE,LTC2944_DISABLE_ALCC_PIN,LTC2944_SHUTDOWN_MODE
  uint8_t curCode;
  uint8_t setCode;
  int8_t ack = 0;
  ack |= LTC2944_read(i2c_address, LTC2944_CONTROL_REG, &curCode);
  setCode = ALCCMode | (curCode & B11111001);//B[2:1]
  ack |= LTC2944_write(i2c_address, LTC2944_CONTROL_REG, setCode);
  return(ack);
}

int8_t I2CLTC2944::LTC2944_set_shutdown(uint8_t i2c_address,uint8_t shutdown)
{
  //"ALCCMode"  must be one of the defined symbols:
  //    LTC2944_SHUTDOWN_MODE,LTC2944_SHUTDOWN_MODE_UNDO
  uint8_t curCode;
  uint8_t setCode;
  int8_t ack = 0;
  ack |= LTC2944_read(i2c_address, LTC2944_CONTROL_REG, &curCode);
  setCode = shutdown | (curCode & B11111110);//B[0]
  ack |= LTC2944_write(i2c_address, LTC2944_CONTROL_REG, setCode);
  return(ack);
}

int8_t I2CLTC2944::LTC2944_set_ACR_full(uint8_t i2c_address)
{
  //set ACR to 0xFFFF
  uint8_t curCode;
  uint8_t setCode;
  int8_t ack = 0;
  ack |= LTC2944_write(i2c_address, LTC2944_ACCUM_CHARGE_MSB_REG, 0xff);  
  ack |= LTC2944_write(i2c_address, LTC2944_ACCUM_CHARGE_LSB_REG, 0xff);   
  return(ack);
}

2.调用方法及测试代码

编写测试代码如下。注意我的Rsense=20mΩ，M的值保持为默认值4096我没有修改它。

#include "Wire.h"

#include "LTC2944.h"


I2CLTC2944 objI2CLTC2944(&Wire1);
const float resistor = .020;   //我的Rsense是20毫欧的

void setup() {
  Serial.begin(115200);
  pinMode(14,OUTPUT);
  digitalWrite(14,HIGH);//打开外围设备供电，用不到就删掉

  uint8_t data;
## 最后

**自我介绍一下，小编13年上海交大毕业，曾经在小公司待过，也去过华为、OPPO等大厂，18年进入阿里一直到现在。**

**深知大多数Java工程师，想要提升技能，往往是自己摸索成长，自己不成体系的自学效果低效漫长且无助。**

**因此收集整理了一份《2024年嵌入式&物联网开发全套学习资料》，初衷也很简单，就是希望能够帮助到想自学提升又不知道该从何学起的朋友，同时减轻大家的负担。**

![img](https://img-blog.csdnimg.cn/img_convert/10824e64de70b1d49cd1d014fa037bf8.png)

![img](https://img-blog.csdnimg.cn/img_convert/bc3ee57e6acf81c1cac59cc4de6f906a.jpeg)

![img](https://img-blog.csdnimg.cn/img_convert/3eef4bf08434d64e35f97af87d4e331e.png)

 ![img](https://img-blog.csdnimg.cn/img_convert/6885a26a70f0e61c15abc383efea23f9.png)

![img](https://img-blog.csdnimg.cn/img_convert/34d5df36ae80e8fa618ee545148ee7f0.png)

![img](https://img-blog.csdnimg.cn/img_convert/e1e720cf46a0818b3d8c8a83df35cb87.png)

![](https://img-blog.csdnimg.cn/img_convert/ad4bb2216f1e18f8cba2fe326c54f1ec.png)

 

**既有适合小白学习的零基础资料，也有适合3年以上经验的小伙伴深入学习提升的进阶课程，基本涵盖了95%以上嵌入式&物联网开发知识点，真正体系化！**

[**如果你觉得这些内容对你有帮助，需要这份全套学习资料的朋友可以戳我获取！！**](https://bbs.csdn.net/topics/618654289)

**由于文件比较大，这里只是将部分目录大纲截图出来，每个节点里面都包含大厂面经、学习笔记、源码讲义、实战项目、讲解视频，并且后续会持续更新**！！


存中...(img-zakGwtlR-1715587520429)]

[外链图片转存中...(img-NqzQ4zNJ-1715587520429)]

 [外链图片转存中...(img-SJVMgf8c-1715587520430)]

[外链图片转存中...(img-9LEWiIER-1715587520431)]

[外链图片转存中...(img-UKLhsEvS-1715587520431)]

[外链图片转存中...(img-h5oYhSzu-1715587520432)]

 

**既有适合小白学习的零基础资料，也有适合3年以上经验的小伙伴深入学习提升的进阶课程，基本涵盖了95%以上嵌入式&物联网开发知识点，真正体系化！**

[**如果你觉得这些内容对你有帮助，需要这份全套学习资料的朋友可以戳我获取！！**](https://bbs.csdn.net/topics/618654289)

**由于文件比较大，这里只是将部分目录大纲截图出来，每个节点里面都包含大厂面经、学习笔记、源码讲义、实战项目、讲解视频，并且后续会持续更新**！！

DAMO开发者矩阵

DAMO开发者矩阵，由阿里巴巴达摩院和中国互联网协会联合发起，致力于探讨最前沿的技术趋势与应用成果，搭建高质量的交流与分享平台，推动技术创新与产业应用链接，围绕“人工智能与新型计算”构建开放共享的开发者生态。

更多推荐

coze+openclaw 机器人权限批量配置技巧

DAMO开发者矩阵

从0到1搭建AI流量闭环：矩阵跃动龙虾机器人+GEO的技术选型与实操指南

AI流量闭环，本质是依托AI技术打通“公域占位引流→精准筛选触达→私域承接沉淀→自动化转化→数据反哺优化”的全链路，以AI替代传统人工的重复性操作，实现流量从获取到变现的自动化、可量化、可迭代流转。其核心价值并非“自动化”本身，而是三个核心落地优势，也是技术选型的核心导向：降本增效：替代人工完成内容分发、账号管理、用户互动、线索跟进等重复性工作，单人可管控数十个矩阵账号，运营成本可降低70%以上，