How to interface 24-bit del sigma 8 channel ADC ADS1278 with Tiva TM4C129XNCZAD microcontroller?

I suggest SPI, as it is the ONLY digital interface the ADS1278 has.

There are TivaWare SPI examples, and the ADS1278 manual.

Sunil Patel said:

Please give suggestions how I can connect both ADS1278 & Tiva TM4C129XNCZAD

A 24 bit ADC is a very (serious) device - the nature of your questions suggests that you may be "over-matched" in effectively & properly marrying these two.

Do you (really) need 24 bits - and are you aware of the design details and expertise to harness the full performance of such a device?

At a minimum - I'd proceed only with an official (i.e. expensive) ADC Eval board.   And then comply fully w/all of the vendor's guidelines.

Our tech firm always follows "KISS" - your uncertainty regarding interface points to the need to (first) experiment w/MCUs SPI ports via connection to far simpler - and much more "forgiving" basic EEprom.  

Small - incremental - understood "movements to the goal" most always prove faster/better & longer lasting...  (and I cannot imagine that vendor's 18 bit ADC would not fully satisfy your (unexpressed) need...)   Unjustified complexity will not prove your friend...   (24 bits is NOT for a beginner...)

(24 bits is NOT for a beginner...)

You are right, for sure.

I wanted to add "I'm pretty sure you are not able to use more than 14 bits of your ADC resolution." to my post, but I dropped it, and rather hurried up for my lunch ...

You can't expect someone to master such advanced HW design tasks, if he doesn't realise which interface an ADC has (not to speak of the MCU...).

To add another two cents of mine:  Assuming Vref=3.3V, this gives you 197nV (nanoVolts) per LSB. Not sure if the OP understands what this means ...

f. m. said:

You are right, for sure.

Mais certainement, mon ami.

Pity that (only) outsiders have the freedom/guts to note (and comment) that, "Emperor ain't wearing NO clothes!"

Only thing missing from this clear "over-reach" is the development & attachment of, "Hydrogen Fuel Cell" which will be (later) revealed...

From the wording/vagueness of this thread - one doubts any, "high-end product" is in the works...

Your "trusty" 16 bit I2C & our 18 bit SPI ADC satisfy all but the (most) high-end needs.

Should not there be (some) attempt to match poster's experience/skill level w/their (most always) over-reaching desires?

Should not there be (some) attempt to match poster's experience/skill level w/their (most always) over-reaching desires?

This was exactly my point.

How can one expect someone to master such an advanced and demanding hardware design (supply/ref. voltage stability, EMI ruggedness, temperature/aging drift stability), if he proved not capable of reading and cross-referencing simple datasheets by himself?

And not even an attempt to explain where the 12 bit internal ADC fails to meet the requirements ...

Thank you all for your post

I require 24 bit high speed ADC because I need Precision in Micro level As my application in patient monitoring

I knew that SPI is for communication of ADS1278 but tiva c seriec having SSI port thats why I am doubting and Yes I have gone through all details of voltage and current to be handled

Thanks again

I require 24 bit high speed ADC because I need Precision in Micro level As my application in patient monitoring

I think you mix up precision and resolution here.

Resolution means dynamic range, and I don't know any human body parameter that needs 7 (seven) orders of magnitude for measuring. I believe a 12 .. 14 bit ADC with appropriate preamplifier/impedance converter would serve you much better.

I knew that SPI is for communication of ADS1278 but tiva c seriec having SSI port thats why I am doubting...

Well, reading datasheet contains sometimes more than comparing catchwords. Sometimes, different companies use different names for technologies (including bus systems), albeit technical identical. Quite often, this has a legal background.

...and Yes I have gone through all details of voltage and current to be handled

Can you, for example, specify the conversion error caused by SPI communication crosstalk, or the total conversion error per degree °C/°F in temperature drift ?  (rhetorical question ...)

sunny thummar said:

I require 24 bit high speed ADC because I need Precision in Micro level As my application in patient monitoring

Nothing in that writing does anything to confirm your (real) need for 24 bit and/or high speed!   (i.e. 18 bits would not work?   And what is "high speed?)

You are aware that along with demanding, technical, engineering details/requirements - you must also satisfy regional safety/health regulatory agencies. 

Past suggestion (use always/only KISS) stands.   Your chance of success w/24bit ADC & complex MCU - especially if you've not used similar - w/success - recently - seems extremely unlikely.   Small, methodical, simpler steps do far more to advance your understanding & capability.   Starting with the most complex/demanding - despite vendor's (seeming) blessing - is not "best/brightest" path toward success...

f. m. said:

My worry is that, when the OP has finished the design, he finds out that it mainly measures the local EM field density, room temperature, and wind velocity, with some very small disturbances by the actually intended parameter...

 Uh oh.. this is a great idea to measure air ionization... :D

 It resemble the same come some time ago asking do cheaper tiva EGC measurement than DSP and then I discovered original application was 16 bit to have decent floor noise and to filter out unwanted noise only dual core DSP can do and at cheaper price too...

  Sometimes before to try device is necessary completely grasp what is underneath. Patient monitoring @24bit  eg patient ECG require an ULTRAFAST multicore DSP.. so 24bit are definitive overkill and useless too.

 Hey guy can I have suggested an ultrafast 32bit converter to measure devil when is lurking? I don't know why I never find a similar converter and new 32 bit processor just have only 12bits.. (:D)

 Asylum for devil still is here...

f. m. said:

certainly no reference to any poster here

Indeed - my hand (still) bears such scars.  (despite your disclaimer)

Along w/measures plagued w/"local EM field density, room temperature, wind velocity, etc." the successful marriage of ADC board layout, interconnect and "match of MCU's SPI to manage 24 bits + conversion protocol of that ADC" will (almost certainly) obscure the source of the dominant error(s)!

Rejecting KISS - climbing Kilimanjaro when small hill provides good challenge - (even and especially when vendor approves) will almost certainly derail & delay progress - and retard "real" learning/understanding...

Might some forum policy require (some) review when ALL outsiders (strongly) advocate against - while vendor (stands alone) encouraging?...

Might some forum policy require (some) review when ALL outsiders (strongly) advocate against - while vendor (stands alone) encouraging?...

That's probably a delicate situation for a TI employee on this forum.

On the sales side, TI might encourage any buy.

On the support side, they might realise this is slighty over the "candidate's" head, and frustration might discourage him, thus not furthering the companies image.

IMHO the TI employees present on this forum seem to handle such cases not unreasonable, as far as I can assess it. (I assume company guide lines forbid them to call a spade a spade, i.e. call a lazy bum a lazy bum ...). And I assume their influence on forum policies are limited.

In other (competitor's) fora, company employees doing barely more than acknowledging bugs or confirming release dates.

f. m. said:

That's probably a delicate situation for a TI employee on this forum.

My friend - that's exactly why I petitioned for stronger (i.e. SOME) forum management guidance for such "over-matched" requests.

I'd ask you:

a) are not other tech items - of far greater value - to far many others - laying dormant?

b) must not the (sole) vendor rep here "make such decisions" EVERY SINGLE POST?   Is that (at all) efficient?  Does it not stress - break tech focus?

c) by outsiders, "Banging the drum" for some logic - far better poster guidelines (i.e. SOME Guidelines) might forum management "hear the cry?"

Or we can do nothing - have endless posters become becalmed/condemned by unhighlighted PF0/PD7, improperly marked 0-ohm Rs on L-Pads, and the entirely different set-up/config/handling of certain peripherals upon the newest TM4 series.

When a resource is SO limited - does it not make sense to (somewhat) limit and focus it to "MOST GOOD - for MOST USERS?"   (that's not being done - this post and multiple others - and needed fixes & far greater, required tech detail - suffer as the direct result...)

Comparing here to the other ARM forum (you/I/others frequent) is a straw-man argument.   The sins of another should not flow unto us - nor raise our stature.  

If we care about this forum - and can present well-reasoned suggestions for improvement - should we "shut up" remain idle?   (that's of course easiest)

You are surely right.

Unfortunately, these are (IMHO) the consequences of sales people having a say in such issues. BTW, with the term "sales people", I include polititians, which are of the same mindset. Knowledge and understanding are no longer valued items in the western culture. Short-term gain is always preferred over long-term strategy. And at the point of failure, the leadership (upper management of ruling party, respectively) is fired and replaced with a new one, presenting the same ideas in another hue ...

This remembers me of the nice proverb (don't know the author): "Those who can, do. Those who can't, teach. Those who can't teach, administer."

I strongly believe many TI employees I mentioned are on your/our side. But according to my experiences, those things only change when the is a (real or perceived) influence on sales numbers ...

Comparing here to the other ARM forum (you/I/others frequent) is a straw-man argument.   The sins of another should not flow unto us - nor raise our stature.

True, it should never serve as an excuse. But wise men would learn even from the mistakes of others. And BTW, I have a hard time to understand the strategy behind this competitor's forum. It's MCU branch is basically a one-man-show, kept up by a non-employee. On the other side, this company is heavily pushing an idiot-proof (and bug-ridden) "Point-And-Click" software. Do they want to attract the superficial and ignorant slackers currently flooding most MCU fora ?

If we care about this forum - and can present well-reasoned suggestions for improvement - should we "shut up" remain idle?   (that's of course easiest)

Hell, no. While we keep up the pressure, some people need to realize who is the intended target audience of this forum.

And finally, sorry for ranting ...

f. m. said:

   And finally, sorry for ranting ...  

If your quite clear - and heartfelt comments - qualify as a "rant" - rant on mon ami...

How much of this vendor's (sole) rep's time is devoted to:

a) I2C "fix" (especially the newer TM4C) which requires the (unusual) new wait scheme

b) uDMA - noted & agreed by vendor as, "far too brief" as currently described w/in MCU Manual

c) Bootloader - has anyone, anywhere, got that to run fully/completely - upon the first go?

d) better detailing/alerting to the dreaded, "JTAG Lockout"

e) old, inappropriate Stellaris code for "pre Tempest" M3 MCUs appears (too often) here - for use w/newer MCUs.  (w/less than Stellar results!)

Does this not point to a superior method - the creation of "serious, well detailed, new App Notes/examples" (per the above) - which are provided as, "auto response" to each new post - targeting those (quite predictable) subject areas?   Can it be "fun" for (sole) vendor rep (even while amassing 90K "points") to repeatedly deal w/essentially the same issue?   (can you say, "Burn out?")

To your point as to Sale's/Marketing's "intrusion" - might you care to "guess" the (likely) volume purchase resulting from 24 bit, ADC seeker?   Would not 1000 or 5000 "other Sales" far more likely result - from, "Speeding, Easing & Enhancing" the development effort of the (non 24 bit) masses?  (Ans: hell yeah!)

Unfortunately I agree w/many of your (top of post) well-thought/presented points.  

Devoting great time/effort to so over-matched, extreme minority use-case users, will not achieve Sales Quotas - and will (instead) dilute, delay and impede the development of multiple, necessary "fixes" (some identified here...) "sure" to boost sales & reduce (needless) client pain/suffering/frustration...

Devoting great time/effort to so over-matched, extreme minority use-case users, will not achieve Sales Quotas - and will (instead) dilute, delay and impede the development of multiple, necessary "fixes" (some identified here...) "sure" to boost sales & reduce (needless) client pain/suffering/frustration...

Unfortunately, to understand the hopelessness of encouraging such endeavours (like this 24-bit ADC idea) requires a great amount of technical knowledge and insight, which is neither present nor required, often not even encouraged in some management/sales circles. Too much knowledge intricates the decision-making process, as one management rule goes (honestly !).

And here is the circular reference. I could imagine that employees dealing with such issues often avoid fruitless discussions with leadership, and prefer luke-warm reactions to "spam posters" on the forum. And they might be well aware that such (enforced) strategy might be harmful at the long run, since it lowers the niveau and drives experts away, not to mention the wasted resources...

f. m. said:

Hell, no. While we keep up the pressure, some people need to realize who is the intended target audience of this forum.

And finally, sorry for ranting .

 Hi F.M. I just subscribe all you wrote, my perception is very close to your. I am just sorry have our Amit here doing a so huge useless work.

 This forum can be of great value but opening in this manner dropped a lot, when TI change FAE is just a bad view of problem, when selling drop they where dropped forever to hobby market only and never regain market... Opening this forum as public too is not a good idea when someone has need of professional help.