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ADS8689: 32 bits register reading command sequence

mukesh Prajapati
Prodigy 110 points
Part Number: ADS8689

What is the command sequence to read device id 32 bits register

As per the datasheet we can send read HALF_WORD command but,

1) does it read MSB half word or LSB half word ?

2) should we need to send more 16 clocks after sending command of read half word?

3) Should we send read half word command twice to read whole word(32 bits) ?

  • 0
    TI__Mastermind 37955 points

    Hi mukesh,

    1) Half word means 16-bit regarding a 32-bit internal register, below is an command example to use READ_HWORD command to read from ALARM_H_TH_REG Register.:

    • Data frame to read the 16-bit (0~15 bit) of 32-bit register:      <11001_xx> <0_0010_0100><00000000><00000000>
    • Data frame to read the 16-bit (16~31 bit) of 32-bit register:    <11001_xx> <0_0010_0110><00000000><00000000>

    2) Yes, the SCLK clocks in first frame F are used to send the command to the ADC device, and the clocks in second frame F+1 are used to shift out 16-bit content of the register from the device to the microcontroller. Notice that the second frame is required because the command gets executed at the rising edge of CONVST/&CS signal.

    3) Yes, see the command example in 1).

    Thanks&regards,

    Dale