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Forum Post: RE: ADS1258 Idle Mode Question on How to Enter Sleep Mode

August 5, 2014, 11:08 am
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Hi Eric,

Good to hear from you and thanks for the update! Sounds like you're making great progress!

The ADS1248 is a great option and would bring your power consumption down significantly! One thing to be aware of is the required external capacitive load needed with the internal reference. This reference capacitor increases the reference settling time.

Another great option may be the ADS1220. It's power consumption is comparable to the ADS1248, but would allow you to turn it off and wake it up quickly. It's internal reference does not require an external capacitive load. Therefore, the internal reference settles within the 50us that is also needed for the internal oscillator to settle. The ADS1220 also holds the register settings in power-down mode.

Best Regards,
Chris

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Forum Post: RE: DAC161P997 4-20mA output..

August 6, 2014, 10:00 am
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Sorry, I am not sure what you are asking.   The loop current is not changing as you send an update?

Mike

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Forum Post: RE: ADS1292 AVdd disconnect

August 6, 2014, 10:04 am
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Hi Corey,

I did some tests to look into this using our ADS1292EVM and GUI software. A few things had to be modified:

  • L3 (inductor connected to AVDD supply) was uninstalled / replaced to disconnect / reconnect the supply
  • AVDD is used to power the internal oscillator, so I installed an external oscillator and the required discrete components to provide an external CLK. 

After powering on the EVM and starting the GUI, I wrote to some registers and ensured I could read out the internal Test Signal. Then I disconnected AVDD (removed L3). At that point, I tried to change a couple registers and determine if SPI communication was still possible. At least with our software, it was not. A Register Read yielded all "0s."

When I restored AVDD, the part powered back on with its Device Default settings. 

So based on my observations, disconnecting AVDD only (leaving AVSS, DVDD, DGND intact) should not damage the part; however, I was not able to write to registers during this time, and previous register settings were not retained. You will likely need to issue a HW / SW reset to the device after power up (following Power-On Reset protocol) and rewrite your registers.

I hope this is clear. Let me know if you have any questions.

Regards,

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Forum Post: RE: ADS1256 chain configuration

August 6, 2014, 10:24 am
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Hi Sasa,

I'm glad I could help!

Please let me know if you have any additional questions.

Best Regards,
Chris

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Forum Post: RE: DAC161S997GUI

August 6, 2014, 10:26 am
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Sorry there is not a Linux version of the software.

Now that the VISA driver is installed, try uninstalling the DAC161s997 GUI software and then reinstalling.

Mike

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Wiki Page: Presentations / Training

August 6, 2014, 10:32 am
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Forum Post: frequency measure

August 6, 2014, 10:35 am
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hi sir,

I would like to know whether any IC  available to measure frequency  of a transformer. we actually wanna to calculate the flux of a transformer, as V/f is proportional to flux... we want to measure frequency followed by voltage and combine them to get the flux// Please help me to find the device available  

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Forum Post: RE: ads1110

August 6, 2014, 11:06 am
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Hi Joseph,

I just emailed you the schematic. Please check them if you have a chance.

Thank you

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Wiki Page: SPI Guide for TI ADCs

August 6, 2014, 11:16 am
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In Progress...

This guide will discuss how to communicate with TI ADCs via a Serial Peripheral Interface (SPI).

We will cover:

  • Initial Configurations
    • SPI Mode
    • SCLK Frequency
  • ADC Timing Requirements
    • Waiting for /DRDY
    • Overwritten/corrupted data
  • MSP430 Example Code
  • Troubleshooting
  • Questions
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Forum Post: ADS1298 for sEMG

August 6, 2014, 12:38 pm
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Purpose : For sEMG

Condition :

 I have prestage for INP(a few filters and amplifiers before ADC)

AVDD : 5V, AVSS : 0V, PGA=1

Single input INP : swing around 2V(limited from 0V to 5V by prestage OPAMP)

 

1.1   when I use internal reference 4V and connect INN to 0V,

INP swings around 0V? so it loses signal under 0V?

1.2   internal reference 4V but INN to 2V common voltage same as INP,

INP swings around 2V? in theory, range is from -2V ~ 6V but in practice, 0V~5V? or 0V~4V?

Which one is right?

1.3    Vin = INP –INN

At 1.1 Vin = INP -0V = INP and at 1.2 Vin = INP – INN = INP – 2V(AC signal swings around 0V). which one is right?

And in which situation will I get 7FFFFFh code? Over Vref 4V?

2.1 internal reference is 2.4V and INN is connected 2V

     What is INP range? Theoretically -0.4 ~ 4.4V but in practice 0~4V? or 0~5V?

     And here when INP is over 2.4V, output code is 7FFFFFh?

3.electrode can be connected to ADS1298 directly for sEMG? or it needs signal conditioning?

4. when I don't use pace detection,should I connect TESTP_PACE_OUT1 and TESTN_PACE_OUT2 to AVDD?

Thanks for answer

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Forum Post: RE: RE: ADS1232 High Power Consumption in Power Down Mode

August 6, 2014, 1:01 pm
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HI Igor,

I moved your post as the topic changed.  This is an issue I have not seen before with the ADS1232. I will assume that you are using the PDWN pin to enter power down.  Make sure that on start up you follow the power-up timing sequence as it relates to the supplies and the PDWN pin.  This information is shown in Figure 39 of the datasheet.

Best regards,
Bob B

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Forum Post: RE: TLV320AIC3106 problem ... sudden connection between ADC and DAC

August 6, 2014, 1:11 pm
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My pleasure! I look forward to seeing the results of your test.

To answer your question about DAC_L3, you are correct that there are only two dacs, one left and one right. The DAC_L3 refers to which line the dac is being output to. This is controlled by register 41 on page 0. DAC_L3 feeds from DACL directly into LEFT_LOP. This is different from, for example, DAC_L1 which goes into a volume control mixer (controlled by R82 page 0) before it goes to LEFT_LOP.

Hope this helps!

Nate

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Wiki Page: EVM Troubleshooting

August 6, 2014, 1:32 pm
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Please see this group of posts for troubleshooting EVMs

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Wiki Page: Music won't play with USB streaming

August 6, 2014, 1:55 pm
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There are several reasons that music won't play on an EVM for USB streaming. Let's address a couple of them here. Note that this page will apply to essentially any device using the TAS1020B USB to I2C/I2S device.

Always refer to the EVM's user's guide as an initial point of reference for configuring the device

1) Check that the EVM is selected as the default device.

To do this, open up control panel and select "Sound"

Next, right click the USB-AudioEVM and select "Set as Default Device"

Now check to see if music is playing.

2) If you get the error "Windows Media Player encourtered a problem while playing this file."

or in YouTube "An error occurred, please try again later. Learn More"

 To resolve this go to control panel -> sound

right click USB-AudioEVM and select "properties"

Then select the "Advanced" tab

Next try to change the sample rate from 48000 Hz to 44100 Hz or vice versa.

Now check to see if music can play.

3) Remember that register settings for audio converters are all volatile memory, so be sure to use the GUI or I2C script after every power cycle as many devices do not play music unless they are programmed first.

As always, if you ever have questions about configuring an EVM please feel free to post them to the e2e forum!

Nate

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Forum Post: RE: PCM5102A Click/Pop between track changes

August 6, 2014, 2:18 pm
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Hello Napat,

I just got some extra information regarding this from the systems team. The pop and click you are hearing is an inherent function of the device when it goes into mute mode. To avoid this happening (and avoid the clicking) you can add a small amount of dither to keep the DAC from seeing all zeros. If this is not possible then an external mute circuit would have to be added anytime the I2S data was all zeros.

Please let me know if you have any additional questions,

Nate

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Forum Post: RE: ADS1243-HT conversion rate?

August 6, 2014, 2:54 pm
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Ron,


Based on the equation given on page 35 of the datasheet and on the setup information given, the data rate should be 7.629Hz. This data rate should be exact, since data comes out after an exact number of clock cycles for each conversions. With 7.629Hz, the data should come out every 131 ms.

If you're measuring this with an oscilloscope (by checking the /DRDY line), it's possible your scope trace lacks the resolution (or is on a setting with too little resolution) to see each /DRDY pulse because the pulse is pretty narrow compared to the data period.


Joseph Wu

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Forum Post: RE: ADS1248 system monitor

August 6, 2014, 3:26 pm
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Houssem,


I'm not sure what exactly is the problem, but my guess would be an error in the communication. I would read back register 02h to make sure that the part is in the configuration that you expect. You can also read back the other registers just to make sure of the configuration.

Along this same line, it might be that you have toggled the MUXCAL bits but are setting it to 001 each time. That would take the AINP and AINN and tie them together at mid-supply. That would be close to 0V as an input. If the device is uncalibrated, then this might be close to the value of 0.000062V that you see (I assume that you're reading something like 0000FEh as the input, with some amount of change in the reading).

One other possibility, is that you might get some errant readings if the reference isn't turned on, or isn't connected. This is a less likely possibility to check after reading back the registers.


Joseph Wu

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Forum Post: RE: adc16dx370EVM to Xilinx ZC706

August 6, 2014, 4:01 pm
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Thank you. We will check the suggestions. Actually we can see a ramp and a sine wave but the values are not correct.  It might be an issue with sync.

Is it possible to get TSW14J56EVM Altera FPGA  source for a reference?

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Forum Post: ADS8864 Power Sequencing

August 6, 2014, 4:03 pm
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Hi, 

I am working on a design with and ADS8864. The analog section has some signal condition with a couple of amplifiers and a voltage reference with no shutdown pins. The problem is, I need to shut down the analog section for extensive periods of time while keeping the digital section powered. The options I can think of are:

a) Shut down the analog section including AVDD using a load switch but keep DVDD powered up. There is no information on power sequencing in the data sheet so I am not sure if this isn't going to damage the device. Also I am not sure if there will be increased leakage currents.

b) Shut down the analog section including AVDD and DVDD of the ADS8864 using a load switch. In this case the SPI lines would remain connected to the uP which will remain powered all the time.

c) Replace the OPAmps and voltage reference with similar ones but with shutdown.

Which one is the best solution and most importantly, which has the loses average current consumption?

Many thanks in  advance for your help.

Christof

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Forum Post: RE: ADS1292 - RLD External Reference

August 6, 2014, 4:10 pm
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Same problem happening for me. I am using +2.5V and -2.5V bipolar supply and RLD is railing at +2.5V. Did anyone solve this issue?

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