AD5592r Sequence conversion mode

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:
https://github.com/analogdevicesinc/EVAL-ADICUP3029/tree/master/projects/ADuCM3029_demo_ad5592r_ad5593r

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

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:

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

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

Measurements:
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:

Demonstration of timing:

Looking forward to your reply,
Marcus

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.