现状确认 #

读取0x12电池状态寄存器得到返回值1100010010000100，根据芯片手册第53页位定义，设备处于睡眠模式且未完成初始化。

具体处理步骤 #

1. 发送唤醒命令触发初始化 #

BQ76952需通过子命令唤醒，在setup()中添加唤醒逻辑（参考手册子命令0x01定义）：

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22, 400000);
  delay(2000);

  // 发送唤醒子命令
  Wire.beginTransmission(BQ76952_I2C_ADDR);
  Wire.write(0x01); // 子命令寄存器地址
  Wire.write(0x01); // 唤醒子命令码
  Wire.write(0x00); // 子命令参数（按需填写）
  Wire.endTransmission();
  delay(100); // 等待设备完成唤醒

  // 后续原有代码不变
  uint16_t subcmdStatus = readWord(0x00);  
  Serial.print("Subcommand Status (0x00): "); 
  Serial.println(subcmdStatus, BIN);

  uint16_t batteryStatus = readWord(0x12);
  Serial.print("batteryStatus (0x12): ");
  Serial.println(batteryStatus, BIN);
}

2. 排查硬件问题 #

• 确认芯片供电电压符合规格，低电压会导致初始化失败；
• 检查I2C总线的上拉电阻是否正常，排查SDA/SCL线路的连接可靠性。

3. 验证寄存器读写顺序 #

当前readWord函数先读LSB再读MSB，若手册规定寄存器为MSB优先，需调整读取顺序：

uint16_t readWord(uint8_t reg) {
  Wire.beginTransmission(BQ76952_I2C_ADDR);
  Wire.write(reg);
  Wire.endTransmission(false);

  Wire.requestFrom(BQ76952_I2C_ADDR, 2);
  if (Wire.available() == 2) {
    uint8_t msb = Wire.read(); // 先读高位字节
    uint8_t lsb = Wire.read(); // 再读低位字节
    return (msb << 8) | lsb;
  }
  return 0xFFFF;
}

4. 尝试硬件复位 #

若唤醒无效，使用芯片复位引脚发送复位信号，再重新执行唤醒流程。

原始代码 #

#include <Wire.h>

// BQ76952 I2C address (7-bit)
#define BQ76952_I2C_ADDR 0x08


void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22, 400000);  // Initialize I2C with default pins (SDA=21, SCL=22)

  delay(2000);

  uint16_t subcmdStatus = readWord(0x00);  
  Serial.print("Subcommand Status (0x00): "); 
  Serial.println(subcmdStatus, BIN); // 10010100000000

  uint16_t batteryStatus = readWord(0x12);
  Serial.print("batteryStatus (0x12): ");
  Serial.println(batteryStatus, BIN); // 1100010010000100
}

void loop(){
  delay(1000);
}

uint16_t readWord(uint8_t reg) {
  Wire.beginTransmission(BQ76952_I2C_ADDR);  // 7-bit address of BQ76952
  Wire.write(reg);                           // Register address
  Wire.endTransmission(false);               // Send repeated start

  Wire.requestFrom(BQ76952_I2C_ADDR, 2);  // Request 2 bytes
  if (Wire.available() == 2) {
    uint8_t lsb = Wire.read();
    uint8_t msb = Wire.read();
    return (msb << 8) | lsb;  // Correct byte order
  }
  return 0xFFFF;  // Error
}

内容的提问来源于stack exchange，提问作者Adam