AVR Freaks

It is still good to know it isn't just my setup...

Thanks,

JC

Hi talllankybastard,

Thanks for the interest!

Atmel responded to my Tech Support question today, acknowledging that this is a Studio bug, and Studio, (at least with the AVR ISP mkII), can't read the Production Signature Row.

I don't have any JTAG devices, as I've always debugged with an LED and an LCD.

Actually, I take that back, I have a Dragon, but I was never impressed that my Version I Dragon could reliably connect to an Xmega.

I do have an STK600 collecting dust in the basement.

I may have to dig it out and give it a try, but this was suppose to be a weekend, quickie, project... (Best of plans).

At this point, this entire project, reading the E5's internal temperature, (in Basic), might get put on the back burner.

I did play around with Studio and found a E5 Xplained board read the internal temp project / example.

I figured out to get it loaded, clicked the right buttons to download it to the board, and I think, (maybe), it ran.

Reading the provided code, the temperature is provided as a variable, which one can read  (watch ?) with the debugger.

That assumes, of course, that one knows how to add a variable to the Studio IDE to watch it.

(Needless to say I'm not a Studio user...)

I guess it would have been too difficult to just show the result on the Xplained board's GLCD...

And it would have taken a lot to flash an on board LED when the project ran and the result was available.

I guess neither of those are necessary if one is actually stepping through the program using the debugger, but I've not gotten that far yet, and really didn't want to learn the IDE and debugger basics at the moment.

Add it would have taken a lot for Atmel to have a document, somewhere, that described, step by step, what it takes to read the internal temperature.

(A description of the ADC setup to read the value, which is WRONG in the Atmel ADC App Note which refers to the Xmega A series...)

And a description of which registers have to be preloaded to enable and set up the internal calibration system.

I'm still counting , but I think I've found four, plus another one that has to have an enable the internal calibration system bit set,

all in addition to the normal ADC register setup.

The info isn't in the Xmega32E5 data sheets, (either one of them, but don't get me started on that!), and it isn't in a separate App Note.

The E5 Internal Temperature is a pretty useless feature when its inner workings aren't documented...  (IMHO).

Take care,

JC

David, I guess I didn't describe my issue very clearly.

There isn't any short, concise, accurate, description of HOW to use the Xmega E5 series internal temperature "feature".

Why include it if there isn't any description of its inner workings?

For the E5 one has to decide whether to set up the ADC in signed or unsigned mode, and in single ended or differential mode, and if in differential mode, which of several possible grounds to use as a input for the negative input.

The ONLY published info on this is roughly one sentence or two, about the Xmega A series, and it is WRONG for the E5 series, and doesn't answer all of the other pertinent questions.

Then the calibration issue.

It says it is calibrated, (IIRC).

It doesn't say one has to turn ON the internal calibration system to be calibrated.

And its not just a matter of reading the Cal L and Cal H bytes and stuffing them into the ADC registers, one also has to load the Offset correction and Gain correction registers, as well.

And what, pray tell, is loading the offset correction actually doing?

How does this differ, if at all, from using a "spare" ADC input to read the Xmega's internal Ground, (OH, which one to use?), and measuring the Offset directly.

Is this just a production line process and aimed at also saving one from using an extra pin for this process, or does it do something else?

Same question about the gain correction register, and function.

If one loads the gain correction does it automatically correct for the ADC's internal gain?

Is this better or identical to reading the room temp and 85'C ADC readings that are suppose to be pre-stored in the Signature Row and calculating the gain oneself?

Does preloading the gain correction negate one needing to do that?

Gee, a simple explanation of the inner workings would go a long way here.

It is nice that the designers presumable know how the system works.

It is, (again, IMHO), a worthless feature without the supporting documentation to know how the system works, and lay out the framework for a customer / designer to use the "feature".

BTY, I'm venting at Atmel, not you!

Take care,

JC

Edit: typo