TI论坛
直播中

凤毛麟角

9年用户 1026经验值
私信 关注
[问答]

使用AFE4490EVM评估板开发,接入手指后,红光信号质量很差,为什么?


  • 大家好,我使用AFE4490EVM评估板开发,接入手指后,红光信号质量很差,完全看不出波形。红外质量相对较好。具体效果请看图片,质量较好的是红外信号,差的是红光信号。
    这通常是什么原因引起的,请大家帮帮分析分析,不甚感激。

    然后指入fluke仿真器,amp 3% spo2:96% PR :75,

    100hz采样率,配置代码如下,
    //8000:500hz 40000:100hz
    u8 i;  WriteCommand(0x00,0x08);
    //Software reset  SystickDelay1ms(5);  
    WriteCommand(0x00,0x00);
    //example  //test 100hz   
    WriteCommand(0x01,30000);  
    WriteCommand(0x02,39999);  
    WriteCommand(0x03,30000);
    WriteCommand(0x04,39998);  
    WriteCommand(0x05,0);  
    WriteCommand(0x06,9998);
    WriteCommand(0x07,10000);
    WriteCommand(0x08,19998);  
    WriteCommand(0x09,10000);  
    WriteCommand(0x0a,19999);  
    WriteCommand(0x0b,20000);
      WriteCommand(0x0c,29998);  
    WriteCommand(0x0d,2);  
    WriteCommand(0x0e,9999);
    WriteCommand(0x0f,10002);
    WriteCommand(0x10,19999);
    WriteCommand(0x11,20002);  
    WriteCommand(0x12,29999);  
    WriteCommand(0x13,30002);  
    WriteCommand(0x14,39999);
    WriteCommand(0x15,0);  
    WriteCommand(0x16,2);  
    WriteCommand(0x17,10000);  
    WriteCommand(0x18,10002);  
    WriteCommand(0x19,20000);  
    WriteCommand(0x1a,20002);
    WriteCommand(0x1b,30000);  
    WriteCommand(0x1c,30002);  
    WriteCommand(0x1d,39999);  
    WriteCommand(0x1e,0x107);
    //Control Register 1 ?  
    //WriteCommand(0x1f,0x000);
    //reserved  WriteCommand(0x20,0x00);
    //Transimpedance Amplifier Gain Setting Register/  
    WriteCommand(0x21,0x00);  
    //Transimpedance Amplifier and Ambient Cancellation Stage Gain Register
    //WriteCommand(0x22,0x00);  
    //LED Control Register  
    //WriteCommand(0x22,0x11414); //5.859375mA
    //WriteCommand(0x22,0x15050); //80/256*75ma=23.4375mA  
    WriteCommand(0x22,0x16650); //80/256*75ma=23.4375mA  
    red:30ma ired:23mA    WriteCommand(0x23,0x00);  
    //Control Register 2
    //WriteCommand(0x24,0x00); //reserved  
    //WriteCommand(0x25,0x00); //reserved
    //WriteCommand(0x26,0x00); //reserved  
    //WriteCommand(0x27,0x00); //reserved  //WriteCommand(0x28,0x00); //reserved  
    WriteCommand(0x29,0x00); //Alarm Register  
    WriteCommand(0x2a,0x00); //LED2 Digital Sample Value Register  
    WriteCommand(0x2b,0x00); //Ambient LED2 Digital Sample Value Register  
    WriteCommand(0x2c,0x00); //LED1 Digital Sample Value Register  
    WriteCommand(0x2d,0x00); //Ambient LED1 Digital Sample Value Register  
    WriteCommand(0x2e,0x00); //LED2-Ambient LED2 Digital Sample Value Register  
    WriteCommand(0x2f,0x00); //LED1-Ambient LED1 Digital Sample Value Register  
    WriteCommand(0x30,0x00); //Diagnostics Flag Register   
    WriteCommand(0x00,0x01);

回帖(2)

杨娟

2025-1-23 10:51:55
  配置完成之后,ADC_RDY就应该有脉冲出来,而且是你配置的采样率的这个频率。你的采样频率是多少,配置的值有没有读出来检查过,是否正确?
举报

surround

2025-1-23 17:34:50
根据您的描述,AFE4490EVM评估板在接入手指后,红光信号质量很差,而红外信号质量相对较好。这种情况可能由以下几个原因导致:

1. 光源问题:红光LED可能存在问题,如老化、损坏或亮度不足。请检查红光LED是否正常工作,可以尝试更换红光LED进行测试。

2. 光敏元件问题:红光光敏元件可能存在问题,如损坏或灵敏度不足。请检查红光光敏元件是否正常工作,可以尝试更换红光光敏元件进行测试。

3. 信号干扰:红光信号可能受到其他信号的干扰,导致信号质量下降。请检查周围环境是否存在电磁干扰源,如手机、无线设备等,并尽量远离这些干扰源。

4. 硬件连接问题:红光信号的硬件连接可能存在问题,如接触不良或线路损坏。请检查红光信号的硬件连接是否正常,可以尝试重新连接或更换线路进行测试。

5. 软件配置问题:您的代码配置可能存在问题,导致红光信号质量下降。请检查您的代码配置是否正确,可以尝试调整采样率、增益等参数进行测试。

针对您提供的代码配置,可以尝试以下调整:

1. 调整采样率:您可以尝试将采样率调整为500Hz,以提高红光信号的质量。代码如下:

```c
WriteCommand(0x00,0x08); // Software reset
SystickDelay1ms(5);
WriteCommand(0x00,0x00); // example
// test 500hz
WriteCommand(0x02,0x81); // 500Hz
```

2. 调整增益:您可以尝试调整红光信号的增益,以提高信号质量。代码如下:

```c
WriteCommand(0x03,0x01); // Red LED gain
```

请尝试以上建议,并根据实际情况进行调整。希望对您的问题有所帮助。
举报

更多回帖

发帖
×
20
完善资料,
赚取积分