ATtiny3217: VREF Register - mistake in documentation?

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Hello there,

 

I'm currently developing a programm which I will debug on the ATtiny3217 XPlained Pro Board, but which will later run on an ATtiny1616 (according to the description of the board, it's the right one to develop for the ATtiny1616). I'm therefore working with both documentations at the same time, trying to notice difference. 

 

A major difference I just found is in the VREF register - according to my understanding the documentation of the ATtiny3217 is just not complete here. 

Technically ADC0, AC0, DAC0 as well as ADC1, AC1, DAC1 and DAC2, AC2 can use the internal reference. In the documentation of the ATtiny1616 the registers to set up the reference voltage are well documented and understandable. Here's a quick overview:

VREF.CTRLA: Set reference voltages for ADC0, DAC0, AC0

VREF.CTRLB: force reference voltages for any of the modules mentioned above

VREF.CTRLC: Set reference voltages for ADC1, DAC1 and AC1

VREF_CTRLD: Set reference voltages for DAC2 and AC2

 

Since the ATtiny3217 provides exactly the same functionality, the registers should look just the same. However, in the documentation only CTRLA and CTRLB are mentioned. It is to be noticed that CTRLB is just the same as in the ATtiny1616 documentation, therefore provides bits to force reference voltages for ADC1, DAC1-2 and AC1-2. Yet, since CTRLC and CTRLD aren't mentioned in the ATtiny3217s documentation, there's no option to set these reference voltages. 

 

Now here's my question: Is the documentation of the ATtiny3217 just incomplete and doesn't cover the registers VREF.CTRLC and VREF.CTRLD or did I missunderstand something here?

 

EDIT: Little side note - when developing in Atmel Studio for the ATtiny3217, one can set VREF.CTRLC and VREF.CTRLD without getting a compiler error. At this point I'm pretty sure we're dealing with a faulty documentation here. 

Last Edited: Tue. Oct 30, 2018 - 09:47 AM
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I suggest that you just experiment.

 

There see to be lots of documentation errors.    I suspect that CTRLC, CTLD registers exist.    However there may be some Silicon bugs.    And that is the reason why they are not documented.

 

Or perhaps Microchip has inherited the same copy-paste features that Atmel was renowned for.

 

David.

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You should report your findings to Microchip support, this is only a user forum.

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I know, old thread, but you wrote:

 

"In the documentation of the ATtiny1616 the registers to set up the reference voltage are well documented and understandable. "

 

But at least on this datasheet (first one that google comes up with) CTRLC and CTRLD are not documented at all:

 

http://ww1.microchip.com/downloa...

 

Just so that future generation know ;) 

 

 

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Download the latest version of the data sheet from the Microchip site.
It has been updated very recently.

 

Last Edited: Thu. Jul 11, 2019 - 10:05 AM
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Latest datasheet for ATtiny1616/3216 can be found here:  http://ww1.microchip.com/downloads/en/DeviceDoc/ATtiny1616-3216-DataSheet-DS40001997C.pdf , and it contains documentation of the VREF CTRLC and CTRLD registers.

 

kabasan, you posted a picture from the higher pin-count version, ATtiny1617/3217. ;-)

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Thanks! 

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typical tiny 1 & 0 series documentation....luckily they updated it last week (I think).

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I was in conversation with the questioner.

 

Now here's my question: Is the documentation of the ATtiny3217 just incomplete and doesn't cover the registers VREF.CTRLC and VREF.CTRLD or did I missunderstand something here?

 

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je_ruud wrote:
kabasan, you posted a picture from the higher pin-count version, ATtiny1617/3217. ;-)

Which is what the thread title mentioned.  We have to follow the thread hijacker's link and infer the rest.

 

 

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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So, just a lot of confusion due to thread hijacking.

 

Anyway, as Moe123 said the tiny datasheets have been updated lately. An easy way to find the datasheet of a device is to just type the following in your browser: "www.microchip.com/<device-name>". If you're looking for ATtiny3217 you just write www.microchip.com/ATtiny3217 and you'll get the device page, where it should be easy to find the datasheet.

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So who hijacked what?