AVR annoyances - a collection of those 'obscure' tips &

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Y'know all those annoying things that took you 2 weeks to figure out, or by accident, or whatever?

I'm makin' a big list of them here:
http://www.ladyada.net/resources...

hopefully useful...or at least enlightening. email me if you have any suggestions. :)

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Did you know there's an AVR Wiki on this site now? That kind of stuff looks like a candidate for inclusion there.

Cliff

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This seems very nice:
http://en.wikibooks.org/wiki/Atm...
any chance to blend the 2?...

Embedded Dreams
One day, knowledge will replace money.

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I would just add:
ATMega128 programming pins are not MISO and MOSI, but DI and DO. Read the small invisible note on the datasheet.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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In case it wasn't obvious from my previous post the official Atmel sponsored AVR Wiki is described here:

https://www.avrfreaks.net/index.p...

(and after that I guess the page at Wikipedia comes in second: http://en.wikipedia.org/wiki/Atm... )

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clawson wrote:
In case it wasn't obvious from my previous post the official Atmel sponsored AVR Wiki is described here:

https://www.avrfreaks.net/index.p...

(and after that I guess the page at Wikipedia comes in second: http://en.wikipedia.org/wiki/Atm... )

ive had a website for a lot longer... ;)
if the avr wiki wants to mirror my info they are welcome to!

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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daqq wrote:
I would just add:
ATMega128 programming pins are not MISO and MOSI, but DI and DO. Read the small invisible note on the datasheet.

oh right. man, i remember that. added!

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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I guess it depends how many "eyeballs" you were hoping for. When this thread and your site are long forgotten people will still be being directed to the Atmel site and, let's face it, anyone who wants to know ANYTHING these days almost always will start at Wikipedia!

Cliff

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clawson wrote:
I guess it depends how many "eyeballs" you were hoping for. When this thread and your site are long forgotten people will still be being directed to the Atmel site and, let's face it, anyone who wants to know ANYTHING these days almost always will start at Wikipedia!

i dont care too much about eyeballs...i just want to collect this data since no one else has.
again, if someone wants to merge the info into their own system, they are welcome to!

limor

ps oh and i dont think my site will be long forgotten any time soon ;)

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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> again, if someone wants to merge the info into their own system, they are welcome to!

These "someone" is *we*, you, me, Cliff, anyone else. It's a Wiki. It's probably also
a good place to move that "inofficial errata" thread from here to (an idea that just
came to me).

Btw., I doubt your website is really older than avrfreaks.net. ;-)

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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dl8dtl wrote:
> again, if someone wants to merge the info into their own system, they are welcome to!

These "someone" is *we*, you, me, Cliff, anyone else. It's a Wiki. It's probably also
a good place to move that "inofficial errata" thread from here to (an idea that just
came to me).

im not really a huge fan of group wikis, i think they often get abandoned when they are 'group projects' because there is no maintainer/moderator. if something is on my site i will always maintain it myself

but i added a link from the avr wiki to the page so there you go!

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Limor,

Illegitimi non carborundum :D

or for the Wiki minded:
http://en.wikipedia.org/wiki/Ill...

Keep us the good work, and if you want to work alone - so be it, all contributions are welcome, and your 'annoyances...' looks like the start of something good.

Smiley

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ladyada, in your list, you say there is already an internal pull up resistor on the Reset pin. How did you discover this? I looked in a mega16 datasheet and did not see anything that indicates this.

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jheissjr wrote:
ladyada, in your list, you say there is already an internal pull up resistor on the Reset pin. How did you discover this? I looked in a mega16 datasheet and did not see anything that indicates this.

that is a damn good question! i *know* i've read it in some datasheet or avr note. i will keep looking and update it with a reference.

thanks for pointing this out to me! :)

EDIT: Found it! Look in your datasheet (personally im looking at the atmega162) for a figure called "Reset Logic" and you will see a "Pull up resistor" also in the table "DC characteristics" there is a value R_RST "Reset Pull-up Resistor" which is 20-100Kohm

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

Last Edited: Mon. Mar 26, 2007 - 05:43 PM
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Hey,

I've been wanting to put a page in the Wiki about commonly broken things, but never knew if there would be enough support for it to warrant it... so I added it myself now that I see there is ;-)

-Colin

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You have a good eye. I would never have found that. Its a shame they make it so obscure in the datasheet.

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Quote:
i dont care too much about eyeballs...

Regardless of how old, big or good your site is, if no one sees it, it is worthless.

Regards,
Steve A.

The Board helps those that help themselves.

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Koshchi wrote:
Quote:
i dont care too much about eyeballs...

Regardless of how old, big or good your site is, if no one sees it, it is worthless.

Ummm... Google lead me to the ladyada site several times. In a way, Google makes the whole internet into one big wiki.

Also, she published the plans for an illegal cellphone busting jammer, >I'd< never build it (hear that FCC?) but it is nice to think when some obnoxious twirp is screaming into their cellphone: "I could bust you up you, your rude SOB..."

Let the anarchist anarch and the wikis wik, the world is big enough.

smiley

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> im not really a huge fan of group wikis, i think they often
> get abandoned when they are 'group projects' because there
> is no maintainer/moderator.

For the avrfreaks wiki, there actually is (the same people you are trusting
for in this forum, basically).

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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dl8dtl wrote:
> im not really a huge fan of group wikis, i think they often
> get abandoned when they are 'group projects' because there
> is no maintainer/moderator.

For the avrfreaks wiki, there actually is (the same people you are trusting
for in this forum, basically).

sure i trust the wiki moderators to look for spam, and maybe put in corrections, but there isn't one person who is in charge of looking out for content and adding it to the wiki. (or at least, thats what it seems like, i could be wrong.) you may say (rightfully) "a wiki is a group effort! of course no -one- person is in charge of adding stuff"

but look at it from my perspective (and i imagine a lot of people think the same way):

someone (say me) has some content (say this typed out list of bookmarks and notes i've collected) and since i have a website that is all set up, with a bunch of content on it already, i post it on my site and drop a line here.

so a couple people say "you are wasting your time putting content on your site, put it on ours instead" (or at least thats what i'm hearing ;) )

well, now i have to maintain 2 sites, maybe 4 (wikipedia, wikibooks, avrwiki as well as mine). suddenly my "contribution" has turned into a burden!

ok so maybe one could say "why bother maintaining your own page at all? you should put all your content on avrwiki and be done with it"

Sure, but I actually do want people to come to my site to check out my content because, well, the more traffic I get the more likely people will head over to the store and maybe buy something that will help me keep doing what i do :)

so my view is: if someone has content you want added to a wiki, ask politely if they'd like to add it. If they dont, ask if they mind if you add it yourself (in case theres some copyright issues). I think that trying to guilt someone into it probably isn't going to work! (But don't tell my mom that, she uses the technique -all- the time :) )

what do you think???

limor

ps. i'd say wikipedia is an exception here, as it has passed critical mass.

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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> I think that trying to guilt someone into it probably isn't going to work!

Sure. Sorry if I left that impression, that wasn't my intention!

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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ladyada
The charm with wiki (and this forum)is that it collects experiences and knowledge from many different people. Normally that gives a larger "bank of knowledge" than one person, no matter how great is able to contain.
Also, you say you don't look for eyballs, then you say you want people to find your site and buy your stuff ???

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Lennart wrote:
ladyada
The charm with wiki (and this forum)is that it collects experiences and knowledge from many different people. Normally that gives a larger "bank of knowledge" than one person, no matter how great is able to contain.

Absolutely. That is why I didn't copyright that page or any other of my resource pages, or nearly any of my projects (Nearly all of it is creative commons or GPL or some other open source license).
That's also why I posted about it here!

Quote:

Also, you say you don't look for eyballs, then you say you want people to find your site and buy your stuff ???

There is no contradiction: "total eyeballs" doesn't matter to me much. Because my site is my sole income, only "eyeballs on my website" count! Putting 'significant' content on another page (even if that site is much more popular) doesn't make people visit my site. Therefore I must put priority on ladyada.net and adafruit.com. Does that make sense?

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Hey limor,

I just took a look at your site. If I have calculated the time frame and location correctly, we may have met. If you were ever at a MITERS event where some guy was giving out necklaces made of P-38 can openers or PICs and 1N4001 diodes, or at a Howtoon party where electric motors were made or marshmallows were flying, I was there.

Some Guy

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jheissjr wrote:
ladyada, in your list, you say there is already an internal pull up resistor on the Reset pin. How did you discover this? I looked in a mega16 datasheet and did not see anything that indicates this.

It's in the data sheet in the block diagram of the RESET system, page 36 in the revision that I have been using.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Someguy22 wrote:
Hey limor,

I just took a look at your site. If I have calculated the time frame and location correctly, we may have met. If you were ever at a MITERS event where some guy was giving out necklaces made of P-38 can openers or PICs and 1N4001 diodes, or at a Howtoon party where electric motors were made or marshmallows were flying, I was there.

Some Guy

your calculations are probably correct! I have certainly haunted MITERS during my years as a student...

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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ladyada wrote:
again, if someone wants to merge the info into their own system, they are welcome to!

Why? There is nothing your web-site has to offer that AVRFreaks or the Wiki site doesn't offer.

ladyada wrote:
im not really a huge fan of group wikis, i think they often get abandoned when they are 'group projects' because there is no maintainer/moderator. if something is on my site i will always maintain it myself

ANd the day that you are run over by a MAC truck, where would we be with you single handedly maintaining/moderating your own personal store of AVR knowlledge?

Koshchi wrote:
Regardless of how old, big or good your site is, if no one sees it, it is worthless.

And the AVRFreaks community is a knowlledge base where many, many AVR users come for direction and advice. While you might want your own private knowlledge database, I'm certian that it will just fade away from the view of AVRFreaks visitors.

The is the Atmel endorsed AVR website. I doubt that your site will be refered to over AVRFreaks.

My vision of AVRFreaks is simply this...

Some come to seek help. Others come to offer help. AVRFreaks is a comon watering hole where, we all can learn and teach. By privitizing your own little knowlledge store, you take away from the AVRFreaks community at large.

Case in point...

I much rather perfer discussing technical issues related to the AVR within the AVRFreaks forums. That is not to say that I don't hold private technical discussions with a select few - I do! But when I recieve 3 to 5 PMs a day asking for help, these individuals are usually refered to direct their specific technical questions to the AVRFreaks forums - where the whole community can gain benifit.

By compartmentalizing the general knowlledge store to all of these privitized web-sites, the effectiveness of the AVRFreaks community is diminished.

Let me put it this way... If I am doing a general Google search for some specific AVR related information and, I just happen to stumble onto your web-site, so be it. But I will more then likely never make a deliberate effort to seek your web-site out - especially where AVR knowlledge is concerned.

The privitizing of AVR related knowlledge simply disrrupts the spirit and intent of the AVRFreaks community.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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ladyada wrote:
Sure, but I actually do want people to come to my site to check out my content because, well, the more traffic I get the more likely people will head over to the store and maybe buy something that will help me keep doing what i do.

And so we get down to the primary motivation...

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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microcarl wrote:
ladyada wrote:
again, if someone wants to merge the info into their own system, they are welcome to!

Why? There is nothing your web-site has to offer that AVRFreaks or the Wiki site doesn't offer.

umm, maybe you think so but i disagree, i have a wide variety of information on my site, from PCB design tips to laser cutter information, to avr tutorials, to electronic projects, videos, forums, diagrams, kits, tips etc. etc. You should check it out!

Quote:

ANd the day that you are run over by a MAC truck, where would we be with you single handedly maintaining/moderating your own personal store of AVR knowlledge?

OK that is pretty ridiculous, you must admit. I could also say "what if a plane crashes into the server where AVRfreaks.net is stored and then the backups catch on fire cause someone fell asleep while smoking"
I think we should agree that "what ifs" should be left out: "what ifs" are just "what ifs" and thats all.

Quote:

And the AVRFreaks community is a knowlledge base where many, many AVR users come for direction and advice. While you might want your own private knowlledge database, I'm certian that it will just fade away from the view of AVRFreaks visitors.

The privitizing of AVR related knowlledge simply disrrupts the spirit and intent of the AVRFreaks community.

You are confusing what is going on, it is NOT a 'private knowledge base' its just my website! i said that ANYONE is free to take this info and put it on any site they want.

I dont even understand why "the AVR community" is freaking out so much here! Why is it so wrong to publish something on my own website? :cry:

Maybe from now on I will only post questions about how to set USART baud rates :)

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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microcarl wrote:
ladyada wrote:
again, if someone wants to merge the info into their own system, they are welcome to!
Carl,

I am going to call you on this one. The logic of your argument is totally flawed on this, and you prove it yourself by the first quote in your post. Note that I formatted the text bold.

I will edit out most of what you wrote and leave the last sentence of you post here:

microcarl wrote:
The privitizing of AVR related knowlledge simply disrrupts the spirit and intent of the AVRFreaks community.
You quoted ladyada saying people are welcome to the information and then you turn around and essentially accuse her of "privitizing" information. Go back and read what you wrote.

Also, if you have a problem with private information, you might just want to have a discussion with Smiley, who actually sells information about AVRs because you seem to have a problem with someone else doing exactly what he does.

Ever yours,

Some Guy

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microcarl wrote:
ladyada wrote:
Sure, but I actually do want people to come to my site to check out my content because, well, the more traffic I get the more likely people will head over to the store and maybe buy something that will help me keep doing what i do.

And so we get down to the primary motivation...

Look up. See those banner ads?
Look left. See those button ads?
AVRfreaks makes money off of content with those ads.

I don't publish stuff to make money, i try to make money so that i can continue to publish stuff :) except I don't have ads on my articles.

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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OK lets all stop bitching because this is just silly. I'd rather talk about avr weirdnesses cause thats what I posted about. :)

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Quote:

Also, she published the plans for an illegal cellphone busting jammer, >I'd< never build it (hear that FCC?) but it is nice to think when some obnoxious twirp is screaming into their cellphone: "I could bust you up you, your rude SOB..."

Where do you see these plans for a cell phone jammer? I don't want to build it either, just for my own curiosity of course.

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Geesh! I guess I'm going to have to take a beating on this one!!! :oops:

But, while I seem to be having difficulty expressing myself on this one, I am sticking with my opinion, at least until I can figure out how I really see the issue.

I'm not against selling stuff. I'm not against personal web-sites! Hell, I want one too but, don't seem to be smart enough to figure out how to go about it.

It's just that after HWNMNBM (for those who remember my involvement in that issue), I have a definite opinion about how and why information is diseminated within the AVRFreaks community.

But, I'm still a newbe, really. so, I'll hold my peice about this until I can sort out my fellings.

Edit:
So ladyada, I offer my apology. :(

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Quote:

I'd rather talk about avr weirdnesses cause thats what I posted about.

OK, I'll bite. Let's talk about this one:
Quote:

DI/DO
Some chips and datasheets refer to DI/DO instead of MISO and MOSI

Could you give me a couple of examples of chips and datasheets that do that?

There are a number of datasheets that use "DI" as "Digital Input" when talking about the priority of signals.

There are a number of datasheets that use "DI" as "Data Input" as part of the USI.

Which use this >>instead<< of MOSI/MISO, outside of the context of USI DI/DO?

Quote:
Reset Pin
Not really an annoyance, but just so you know: its not necessary to have a pull-up 10K (or whatever) resistor on the Reset pin, there’s an internal one already!

(Reference: see “DC characteristics” of any AVR datasheet for R_RST 20-100Kohm pull up resisitor)

Yes, certainly, AVRs do in fact have that internal pull-up that you referred to. Would any of us here leave the /RESET pin unconnected in a production design? Not many; certainly not this cat. Would many/most add a cap and maybe a diode? I think so; certainly this cat does. Would most of us follow something along the lines of the Atmel recommendations in AVR040 app note:

Quote:
To achieve the same protection on Reset as on other I/O pins, an external diode should be connected from Reset to VCC. A normal small-signal diode will do. In addition, a pull-up resistor (10K typical) and a small filter capacitor (4.7 nF) should be connected as shown in Figure 4-7.

This cat and his litter does.

Quote:
Flash corruption from bootloaders
If you have a bootloader (or use spm some other way) you must set the brownout fuses.

Yah, yah, yah. And if you don't want EEPROM corruption, set your bronout fuses. And if you don't want your AVR to execute any series of arbtrrary instructions that may set or clear I/O during periods of Vcc below chip limits, use a brown-out whether internal or external.

Quote:
A/D Pins
Don’t forget, the 2 extra A/D pins on the Atmega8, ‘88, ‘48, and ‘168 can’t be used as general purpose I/O!

Two extra to what? The two more on QFP vs. DIP? True enough; they are not GPIO. Can you check whether the value is above a certain level using the ADC, and even use it to input a string of buttons via a resistor ladder? Yes! Not annoyance; satisfaction.

Quote:
AVCC
Even if you don’t use the A/D converter, AVCC must be tied to VCC

annoyance, or feature? I guess you could say that a floating AVcc does not violate the Absolute Maximum Limits big box--IF you know it won't float beyond the rails. I guess you could say that the bold entry for AVcc:
Quote:
AVCC
Even if you don’t use the A/D converter, AVCC must be tied to VCC

could be ignored. Question: Does anyone do any serious design with any chip-- FTDI, DS1305, AT25xxx, ... -- without looking at a reference design, or looking at the pin descriptions?

Lee

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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theusch wrote:

Quote:

DI/DO
Some chips and datasheets refer to DI/DO instead of MISO and MOSI

Could you give me a couple of examples of chips and datasheets that do that?

The one example I can think of the top o' my head is in earlier attiny2313 datasheets they didn't have MISO/MOSI only DI/DO. (This was later amended but it confused me at first. I figure there's no harm in saying it in case it happens again.)
The reason for mentioning its 'equivalency' (you asked) is I wanted to wire up a programming header for the first time and couldn't figure out where the 2 data wires went :)

Quote:

Quote:
Reset Pin
Not really an annoyance, but just so you know: its not necessary to have a pull-up 10K (or whatever) resistor on the Reset pin, there’s an internal one already!

Yes, certainly, AVRs do in fact have that internal pull-up that you referred to. Would any of us here leave the /RESET pin unconnected in a production design?
Not many; certainly not this cat.

Sure, production designs are different. But a lot of people are just messing around and I often leave it out when doing quick wireups!

Quote:
Would many/most add a cap and maybe a diode? I think so; certainly this cat does.

Actually I don't do this trick, but its a good suggestion, I'll definately add it to the list! :)

Quote:

Quote:
Flash corruption from bootloaders
If you have a bootloader (or use spm some other way) you must set the brownout fuses.

Yah, yah, yah. And if you don't want EEPROM corruption, set your bronout fuses. And if you don't want your AVR to execute any series of arbtrrary instructions that may set or clear I/O during periods of Vcc below chip limits, use a brown-out whether internal or external.

glad to see you agree: i think there's a difference between "a couple of lights twiddle" and "omg what the heck happened to my flash!?!" :)

Quote:

True enough; they are not GPIO. Can you check whether the value is above a certain level using the ADC, and even use it to input a string of buttons via a resistor ladder? Yes! Not annoyance; satisfaction.

well its something to look out for, i made the mistake once myself. and fixed it like you suggest (luckily i didnt need any pullups). but it did trip me up.

Quote:

could be ignored. Question: Does anyone do any serious design with any chip-- FTDI, DS1305, AT25xxx, ... -- without looking at a reference design, or looking at the pin descriptions?

I think you're focused on 'serious' and a lot of people are just mucking about and learning. Do i read every 70 page avr datasheet before playing with a new chip? (hint: guilty guilty guilty!)

i will definately add your notes, thanks for posting them!

limor

ps. I think you're taking the term annoyance seriously, im mostly poking fun at the ORA technical book series...obviously most of these are not annoyances, but they are little things that were not obvious to me or others while starting out. Even 'features' should be pointed out :)

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

Last Edited: Tue. Mar 27, 2007 - 04:39 AM
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Lets make sure the AVR RING is within the freaks website umbrella.

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Quote:

The one example I can think of the top o' my head is in earlier attiny2313 datasheets they didn't have MISO/MOSI only DI/DO.

OOOOKKKKK....--the '2313 does not have an SPI interface per se. So you expect MISO/MOSI for serial ISP? Release ahad both; release B had DI/DO as you said. But the "Serial Programming Pin Mapping" says PB5-PB6-PB7. That causes (forget your original post) a long time to puzzle out?

Quote:

Sure, production designs are different. But a lot of people are just messing around and I often leave it out when doing quick wireups!

So, then why is that an annoyance?

Quote:

glad to see you agree:

...then why isn't the annoyance EEPROM corruption? Many more reports over the 5+ years of this site; much more common to have EEPROM operations than SPM. [Editorial comment: anyone doing a bootloader without "full protection" is >>aiming<< to have a child out of wedlock, or an STD, or both.]

Quote:

well its something to look out for, i made the mistake once myself.

Quote:

Question: Does anyone do any serious design with any chip-- FTDI, DS1305, AT25xxx, ... -- without looking at a reference design, or looking at the pin descriptions?

Quote:

Do i read every 70 page avr datasheet before playing with a new chip? (hint: guilty guilty guilty!)

Quote:

Question: Does anyone do any serious design with any chip-- FTDI, DS1305, AT25xxx, ... -- without looking at a reference design, or looking at the pin descriptions?

How can you apply any other than trivial chip without looking at the pin descriptions or a sample design? Is OE active high or low? Does LATCH work on rising or falling edge? Do address lines need to be tied high or low if not being used? These aren't "AVR annoyances", these are common sense whether slapping something together or a newbie or a board designer.

Lee

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.

Last Edited: Tue. Mar 27, 2007 - 05:46 AM
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retrodan?

JChristoff
Illinois

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Quote:
Quote:

Sure, production designs are different. But a lot of people are just messing around and I often leave it out when doing quick wireups!

So, then why is that an annoyance?

its -not-, in fact, i say so right on the page:
"Not really an annoyance, but just so you know..."

again, i think you are taking "annoyance" more literally than intended, its a light hearted reference to 'windows annoyances' (http://www.annoyances.org/) and other books in that published series. sort of like how i could have named the article "AVR for dummies". that isnt literal, I dont mean to imply any one is a 'dummy. its making fun of how frustrating technology is!

Quote:

...then why isn't the annoyance EEPROM corruption? Many more reports over the 5+ years of this site; much more common to have EEPROM operations than SPM.

Becuase I never had that problem myself, only the SPM problem. But thanks to your note, I just added your comment on eeprom corruption to my list!

Quote:

These aren't "AVR annoyances", these are common sense whether slapping something together or a newbie or a board designer.

Of course its common sense... once you know it :)
but some people dont!

its "annoying" when you buy a programming clip for 8SOIC and it doesnt fit your attiny13 (unless you looked very carefully at the package description)

its "common sense" how the Fuse calculations are done - hey its in the data sheet and dont forget that unprogrammed is 1! - unless you try doing it yourself and you mess up and program the external crystal.

limor

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Quote:
again, i think you are taking "annoyance" more literally than intended,

I am? Let me quote from the first post in this thread:

Quote:

annoying things that took you 2 weeks to figure out

Before I am annoyed for two weeks with hooking up a chip, I think I'd let Acrobat Reader search for DI or AVCC or /RESET or whatever. Takes much less than two weeks, and I don't even have to read [the 70 page (sic) datasheet].

Lee

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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theusch wrote:
Quote:
again, i think you are taking "annoyance" more literally than intended,

I am? Let me quote from the first post in this thread:

Quote:

annoying things that took you 2 weeks to figure out

Before I am annoyed for two weeks with hooking up a chip, I think I'd let Acrobat Reader search for DI or AVCC or /RESET or whatever. Takes much less than two weeks, and I don't even have to read [the 70 page (sic) datasheet].

*slaps head with hand* look i haven't spent 2 weeks figuring out how to calculate fuses. my site often has lightly humored content & hyperbole. kinda like when you said that people who dont protect their bootloaders are looking to get pregnant/STDs.

keep in mind that ive sent out over 1000 AVR chips & kits to very very non-technical people, these are the the kind of things that come up. like you said, for 5+ years people have been wondering why their flash/eeprom gets corrupted when they dont set BOD.

So lets stick to talking about the subject at hand: You obviously know lots about AVR8s so that information is very useful!

limor

ps. you're right, i was incorrect when i said [the 70 page (sic) datasheet]. What I meant to say is "the 200+ page datasheet!" hee hee ;)

pps. if everyone read every datasheet all the way thru, then this forum would be all crickets and tumbleweeds... :roll:

Interesting projects: www.ladyada.net Unique kits: www.adafruit.com

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Quote:

if everyone read every datasheet all the way thru, then this forum would be all crickets and tumbleweeds...

Didja ever think that maybe that would be better? Maybe many of the posts could be avoided by spending an equal amount of time searching for applicable statements in the datasheet for that signal/feature (e.g. "MISO") and perhaps even reading the section containing a pertinent hit?

Where do you think the "experts" on this Forum get their answers for posting responses? They look it up in the datasheets or the app notes or follow pertinent Google hits.

[Actually this conversation reminds me of a thread a year or so ago where the OP proposed quite vigorously that "important" information in the datasheet should be highlighted--boxed, bold, the whole bit. When pressed, no good answers were given as to which information in the AVR datasheets is unimportant enough to everyone to NOT be highlighted.]

Lee

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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Quote:
OOOOKKKKK....--the '2313 does not have an SPI interface per se. So you expect MISO/MOSI for serial ISP? Release ahad both; release B had DI/DO as you said. But the "Serial Programming Pin Mapping" says PB5-PB6-PB7. That causes (forget your original post) a long time to puzzle out?

Actually, I think the "bug" is refering to peoples instinctive urge to route a board with ATMega128, where as SCK is the SCK pin used, but as MOSI and MISO the dreaded DI and DO somewhere IIRC on PORTE are used.
I've done a board like this, and my expresion wasn't pretty.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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> Actually, I think the "bug" is refering to peoples
> instinctive urge to route a board with ATMega128, where
> as SCK is the SCK pin used, but as MOSI and MISO the
> dreaded DI and DO

PDI and PDO. See the Wiki page:

https://www.avrfreaks.net/wiki/in...

also for a historical note about why that's the way it is.

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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jgrunt wrote:
retrodan?

That's the usual explanation for a thread that bloats to three pages in 1 day! ;)

But we're not supposed to mention "Voldermort" are we? (yoiks! I think I just did)

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Quote:
also for a historical note about why that's the way it is.

I'm not arguing, but I know that I'm not the only one who made a nice board for it and ended up with two utterly disgusting wires going on a board...

Historical reasons drove people hysterical.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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> Historical reasons drove people hysterical.

For hysterical raisins...

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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ladyada,

Maybe you could rephrase the title from

Quote:
AVR annoyances - a collection of those 'obscure' tips & etc

to
Quote:
Things you should know about AVR's ...
... that you could find out yourself
... if you only had time
;)

But I guess that's too long huh ?

Here one more AVR-feature, this time in the instruction-set:

inc

and

dec

do NOT set the carry-flag in sreg when crossing the boundary. Coming from the pre-AVR era, this one took some time to discover ...

Nard

A GIF is worth a thousend words   She is called Rosa, lives at Mint17.3 https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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clawson wrote:
jgrunt wrote:
retrodan?

That's the usual explanation for a thread that bloats to three pages in 1 day! ;)

But we're not supposed to mention "Voldermort" are we? (yoiks! I think I just did)

Look at her website. Especially look at: http://www.ladyada.net/make/wave... and look around at other stuff she has posted. She is not RetroDan.

Smiley