ADS8684A: Re configuring ADS8684A while in AUTO SEQUENCE mode

Hi Nishanth,

Sorry for the delay in response, I've looped in another engineer to help with your query. 

Hi Nishanth,

I apologized for missing your query. To reconfigure the channels and scan different channels, you have to switch back to manual mode and select the channels for auto-ch sequence mode(AUTO_RST):

1. Program AUTO_SEQ_EN register to select the channel sequence for next AUTO_RST mode. Note that WRITE Cycle Command requires a minimum of 24 SCLKS after the falling edge of /CS (see the timing and the command format in Figure 107)
2. Issue AUTO_RST command  with 32 SCLKs, see the timing in Figure 105.
3. During auto-ch sequence mode(AUTO_RST), still need to send NO_OP command with 32 SCLKs to ADC.
4. Go back to step 1 and repeat the steps for changing the channel sequence for next AUTO_RST mode. see the timing in Figure 104.

Let me know if you have more questions.

Hi Alex,

Thanks for reminding.

Regards,

Dale

Hi @Dale,

Thanks for your response.

Actually during the first time configuration, my commands are

1.Hardware reset

2.Software reset

3.feature select

4.Range selection

5.Auto Sequence

6.AUTO_RST

For this my IC is giving corresponding values and no problem. But after this, I will acquire data continously, like

while(1)

{

NO_OP commnad to get data in the auto sequence

if(condition) { reconfig_adc(); }

}

In the reconfig adc, The commands that I gave is,

1.MAN_Ch_0

2.AUTO SEQUENCE

3.AUTO_RST

The output is correct till the condition becomes true. That is, when I try to reconfigure the IC, I am getting data from a single channel only.

Am I missing something in the reconfigure_adc function?

Thanks for your time.

Regards,

 Nishanth

Hi Nishanth,

It looks like your AUTO SEQUENCE register programming was not successful when you reconfigured the ADC.

1. Which channel did you continuously get the data from after you reconfigured the device? CH0? Is the data correct for the particular channel?
2. Can you please let me know what commands for MAN_Ch_0,AUTO SEQUENCE and AUTO_RST you sent to ADC to reconfigure the device? Timing plots (/CS,SCLK,SDI and SDO) captured with an oscilloscope will be very helpful to address the issue.

Thanks.

Regards,

Dale

Hi Dale,

Sorry for the delay in response.

1.After re-configuring, I am channel 4 output on all channels.

2.The commands, that I give during re-configuring are,

1.C000 0000 (MAN_Ch_0)

2.030F 0000 (Auto sequence with 4 channels selected)

3.A000 0000 (Auto Reset)

All the data writen to IC are 32 bits with a single 32 bit clock.

Also,In a while I will share the timing plots.

Thanks and Regards,

Nishanth

H Nishanth,

I'm looking forward to seeing your timing plots especially for the transition between different modes. Also, I have a question about your answer to my question 1, is channel 4 you mentioned actually channel 3 regarding total 4 channels(ch 0/1/2/3) on ADS8684A? 

Regards,

Dale