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ADS1298: device ID reading error and only 4 channels can be read

Other Parts Discussed in Thread: ADS1298

Hi,

I have two problems from ADS1298.

firsrt,

I have some ADS1298,and tried to read the device ID from the register 0x00.

It should be read as 0x92,but some ID are read as 0x90,and some are read as 0x92.

the wrong signal is like this: I sent 0x20 0x01 and got 0x90

yellow : DOUT

green : SCLK

blue :  nCS

red : DIN

the right signal is like this: I sent 0x20 0x01 and got 0x92

second,

I can only read the first 4 channels from ADS1298 which the ID are read as 0x90,in the meantime the last 4 channels stay all zeros.

But I can get all 8 channels from the ICs which's ID are read as 0x92 .

 

 

  • Hello Harvey,

    Welcome to our forum!

    Typically, the Device ID is incorrect when the power-on reset sequence is not followed properly. After both analog and digital supplies are established, an extra /RESET pulse ensures the device will properly read its internal registers and enable/disable the correct channels. If the device does not power up correctly, it may think it's a 4-channel device when it should be an 8-channel device. When this happens, Channels 5 - 8 will act as if they are powered down.

    Please refer to the "Initial Flow at Power-Up" on page 85 (Figure 93) and also the "Power-Up Sequencing" section on page 96.

    Best Regards,

  • Hi Ryan

    Your recommendation help me to solve this question.

    Now I can get the correct ID from all devices.