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AD5592r Sequence conversion mode

Does any one use the AD5592r sequence conversion mode (or so called the burst mode)? I am experiencing some issues when use the sequence conversion mode. In general, it works fine but once a while, the AD5592r will send two consecutive channel 1 ADC value out.

for example:

The following is the correct ADC values with the correct channel inex.

0207 11C4 2197 31EB 41D4 519F 61DF 71BC

But once a while the first channel ADC will be sent twice miss the last channel ADC value

0207 0208 11C4 2196 31EB 41D3 519E 61DF

The failure rate is around 0.5%. There is no pattern. it is purely random.

I will appreciate if any one has any answer or solution.


  • Hi,

    Let us know the device schematic and all the device configurations done.

  • Hi vsethia

    I have the same problem, but the error rate is as high as 3%.

    I use EVAL-ADICUP3029 and EVAL-AD5592R-PMDZ, and the connection method is shown in the figure below.

    The code used is the following link:

    Modified only aio_dio_pdmz.c (as attached file)
    My aim is that when I enter "ais a" in the computer serial port it will perform the following actions:
    1. Set I/O 7 to BUSY signal
    2. Set I/O 0 - I/O 6 as ADC pin
    3. Execute Multichannel ADC Conversion Sequence, No Repeat (According to Figure 44 of the datasheet)
    If the first channel appears twice, the error rate is reported in the serial port

  • Please share the entire command sequence.

    When you execute the ADC conversion sequence, is there any wait time before executing? 

  • The following is the entire SPI command sequence after I powered on the board
    SPI clock rate is 1MHz

    3850 FFFF
    0000 0003
    20AB 0000
    3850 3E5F
    0000 00AB
    2003 0000
    7DAC 7DBF
    3000 FFFF
    6800 FFFF
    28C0 FFFF
    2003 FFFF
    4830 FFFF
    4030 FFFF
    500C FFFF
    3850 FFFF
    0000 0003
    386C 0000
    0000 0000
    5A00 0000
    4030 FFFF
    500C FFFF
    4030 FFFF
    500C FFFF
    4830 FFFF
    4030 FFFF
    500C FFFF
    4830 FFFF
    4030 FFFF
    500C FFFF
    540C FFFF
    0000 0000
    4810 0000
    540C 0000
    0000 0000
    4800 0000
    1001 0000
    0000 002D
    0000 003C
    F03C 0004
    1002 0000
    0000 003C
    0000 101C
    E01C 0000

    After the boot init program is completed,
    when I enter "ais a" in the computer serial port it will perform the following actions:
    1. Set I/O 7 to BUSY signal
    2. Set I/O 0-I/O 6 as ADC pin
    SPI commands are as follows:

    3860 7FFF
    0000 0030
    41B0 0000
    207F 0002

    Then it will run an infinite loop, repeatedly reading the ADC value

    107F 187F
    0000 1010
    0000 016E
    0000 114A
    0000 20E9
    0000 30A6
    0000 4025
    0000 5000
    0000 6027

    The picture below is an abnormal situation. The data of channel 1 should appear in the highlighted yellow box, but instead the data of channel 0 appears. The probability of this abnormality is about 3%
    (I have waited for the BUSY signal to be pulled to high level before performing ADC reading)

  • If you want to run the ADC sequencer in infinite loop, set the REP bit to 1.

  • Hi vsethia,

    By your suggestion, if we don't change the command and keep repeat reading the ADC, no matter how long it takes before the next cs falling, AD5592R will keep returned the correct value, right?

    Another question, if we want to stop repeat reading ADC, should we need to add a "nop" before the new command or just send the new reading command?

    Many Thanks

  • Please elaborate on your first question. 

    If you want to keep the ADC sequencer running repeatedly, you need to set the REP to 1 once, and keep the digital patterns running as shown in Figure 43 or 45. and the ADC will return the correct value. 

    For the second question, you need to reset the REP bit and clear all ADC channels in the ADC sequence register. 

    If the REP bit is clear, once all the ADC channels are converted, ADC goes three-state.

  • Hi,

    We have the same issue. The same channel is sometimes clocked out twice.

    HW setup: Custom board with AD5592R-1.

    Initialization sequence:
    1. 0x05AC to SOFTWARE_RESET_REG (0x0F)
        sleep 1 ms
    2. 0x5200 to POWER_DOWN_AND_REF_CONTROL_REG (0x0B)
    3. 0x0030 to GENERAL_PURPOSE_CONTROL_REG (0x03)
    4. 0x0008 to DAC_PIN_CONFIG_REG (0x05)
    5. 0x00F4 to ADC_PIN_CONFIG_REG (0x04)
    6. 0x0002 to GPIO_READ_CONFIG_REG (0x0A

    We poll the ADC every 10 ms at 1 MHz baud. For now we don't want to use repeat (REP) as we don't have SPI DMA and need to free the CPU.
    Tracking command to read ADC channel 2, 4, 5, 6 and 7: 0x10F4.

    Screenshot when issue appears. Channel 2 is clocked out twice. Replies with channel 2,2,4,5,6 instead of 2,4,5,6,7:

    ADC read with fault

    Demonstration of timing:
    ADC timing when fault

    Looking forward to your reply,

  • If you do not want to use the REP function and want to read the ADC data continuously, then do note that after all the channels are converted and read out, the ADC goes three-state. As such, you need to rewrite the ADC sequence register and let the ADC conversion begin afresh, so that you do not read out previous valid data.

  • Thanks for your rapid reply.

    Yes, we are rewriting the ADC sequence register every time as you can see in the first screenshot. We always write 0x10F4, wait more than 500 ns (14 us in the screenshot) and start clocking out data.

    Also note that it is not always the same data that is clocked out twice. It seems to be from a new conversion.

    Edit: We have also tried always clocking out one more word. The error rate was the same (1-2%). When the error happened then, the last channel (channel 7 in our case) was clocked out in this additional word.