• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 48 subscribers
  • Views 408 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Need help with ADS8332 chip.

Jeward Magat
Prodigy 20 points

Other Parts Discussed in Thread: ADS8332

Hi, I am a newbie in using ADC data converters. 

I used ADS8332 and interfaced it with bus pirate. On initialization I wrote [0xe4,0xfd]. Then upon reading the bytes on the CFR register I always get 0xffff on the SDO pin.

I hope you can help me on this.

Thank you very much in advance for your help. 

  • 0
    TI__Expert 5705 points

    Hi Jeward,

    Welcome to the forum!

    There are two ways to configure the CFR on the ADS8332 - with user-supplied data or with default data.

    User-specified values are loaded into the CFR using a 0xE command followed by the desired 12-bit value. The 12 bits are clearly defined in Table 5, and the transaction requires a minimum of 16 SCLK cycles (send 0xE_ _ _). Note that your first instruction only has 4 bits of data following the 0xE command and this is insufficient. 

    Alternatively, you can simply load the default value (which is the 12-bit value 0xFFF)  into the CFR by issuing a 0xF command. This requires at least 4 SCLK cycles and any data bits following the command word are ignored. Please refer Table 4 of the datasheet for more details.

    Going by your write sequence it looks like you are attempting a CFR write (using 0xE command) followed by a default load (via 0xF command). The second instruction pretty much always loads 0xFFF into the CFR, which is why you always see 0x_FFF when you read the CFR. Note that when you read the CFR (using 0xC command), only the last 12 bits correspond to the CFR value (which is 0xFFF as expected). The first 4 bits clocked out are the MSBs of the value stored in the ADC output data register, and can be ignored.

    I hope this helps.

    Best Regards,

    Harsha