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求助，ADS131A04读出的通道数据全部为0

user4093479
Prodigy 30 points
Other Parts Discussed in Thread: ADS131A04, TIDA-00810

各位好，在使用ADS131A04的时候遇到问题， M0-M2，分别为IOVDD,GND,GND，AVDD为5V，外部参考源5V，目前SPI通讯正常，复位能得到正确的响应0xFF04，采用外部晶振4.096Mhz，CLK1的CLK_DIV设置为1，CLK2的ICLK_DIV和OSR分别设置为5和1，即采样率为4.096Mhz/2/10/2048=100hz，通过返回状态确认设置都成功。外部输入接入了3.3V的电压，使能4个通道后，能得到DRDY输出的低电平信号，读取数据后，状态字节0x2200并无异常，但是后面的4个通道数据全为0。

现在不知道问题出在哪里，希望能得到帮助和指导，非常感谢！

  • 0
    TI__Guru**** 295050 points
    您好， 寄存器ADC_ENA的bit ENA[3:0] 是否有配置为1111， 使得all channels power up。
    这几位默认值为0000，即为all channels power down，所以看下这个寄存器是否配置，导致输出disable。
  • 0 in reply to Kailyn Chen
    Prodigy 30 points

    您好，非常感谢回复。4个通道都已经power up，并且通过回复的状态字节确认了设置成功。另外，我在参考官方的TIDA-00810中关于ADS131A04初始化部分代码时发现与datasheet中的流程不符，这点很奇怪：

    //Send Unlock Command
    while(!verifyCommand(ADS131A04_UNCLOCK_ACK))
    {
    sendCommand(ADS131A04_UNCLOCK_COMMAND);
    }

    //Send Wake-up Command
    while(!verifyCommand(ADS131A04_WAKEUP_ACK))
    {
    sendCommand(ADS131A04_WAKEUP_COMMAND);
    }

    //Set Iclk divider to 2
    while(!verifyCommand(WRITE_REGISTER_ACK(CLK1, CLK_DIV_2) ))
    {
    sendCommand(WRITE_REGISTER_COMMAND(CLK1, CLK_DIV_2));
    }

    #if SAMPLES_PER_10_SECONDS == 40000
    //Sent Modclk divider to 8 and OSR=256
    while(!verifyCommand(WRITE_REGISTER_ACK(CLK2, ICLK_DIV_8 | OSR_256)))
    {
    sendCommand(WRITE_REGISTER_COMMAND(CLK2, ICLK_DIV_8 | OSR_256));
    }
    #elif SAMPLES_PER_10_SECONDS == 53333
    //Sent Modclk divider to 6 and OSR=256
    while(!verifyCommand(WRITE_REGISTER_ACK(CLK2, ICLK_DIV_6 | OSR_256)))
    {
    sendCommand(WRITE_REGISTER_COMMAND(CLK2, ICLK_DIV_6 | OSR_256));
    }
    #endif

    //high resolution mode, NO negative charge pump, internal reference; BIT5 is set because the User Guide mentions to always write 1 when writing to this register.
    while(!verifyCommand(WRITE_REGISTER_ACK(A_SYS_CFG, HRM | INT_REFEN | BIT5)))
    {
    sendCommand(WRITE_REGISTER_COMMAND(A_SYS_CFG, HRM | INT_REFEN| BIT5));
    }

    //This is mainly to have everything have a fixed frame size from now on.
    while(!verifyCommand_6words(WRITE_REGISTER_ACK(D_SYS_CFG, HIZDLY_12ns | DNDLY_12ns | FIXED)))
    {
    sendCommand(WRITE_REGISTER_COMMAND(D_SYS_CFG, HIZDLY_12ns | DNDLY_12ns | FIXED));
    }

    //Enable All ADCs
    while(!verifyCommand_6words(WRITE_REGISTER_ACK(ADC_ENA, ADC_ENA_ENABLE_ALL_CHANNELS)))
    {
    sendCommand_6words(WRITE_REGISTER_COMMAND(ADC_ENA, ADC_ENA_ENABLE_ALL_CHANNELS));
    }

    //CRC is valid on all bits received and transmitted, 12 ns after assert DONE when LSB shifted out, CRC enabled
    //12 ns time that the device asserts Hi-Z on DOUT after the LSB of the data frame is shifted out.
    while(!verifyCommand_6words(WRITE_REGISTER_ACK(D_SYS_CFG, HIZDLY_12ns | DNDLY_12ns | CRC_MODE | CRC_EN | FIXED)))
    {
    sendCommand_6words(WRITE_REGISTER_COMMAND(D_SYS_CFG, HIZDLY_12ns | DNDLY_12ns | CRC_MODE | CRC_EN | FIXED ));
    }

    并不是手册中建议的解锁->配置->power up->wake up->上锁。而我是按照手册中建议的流程进行初始化的。