Help needed in order to use 16Mhz Crystal Oscilator

Log in or register to post comments
Go To Last Post
18 posts / 0 new
Author
Message
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
#1
Posted by Kase57: Thu. Feb 23, 2012 - 06:14 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi everybody,

I know this has probably been very well said several times
but i wanted to be able to use 16 Mhz external Osciallator and according to the datasheet i think not only i will need to set CKSEL[3..0] to 1000 - 0101 but also i will need to enable CKOPT since i want to use over 8Mhz

I was just wondered if someone could help me understand this better.
I have been reading that it's possible to program fuses bits directly by using ISP just like you would normally bootload the chip. for example a cmd like "avrdude -c usbtiny -p m32" however i don't know which commands to send to the chip. in terms of setting up Low, High & Ext fuses so i can be able to use 16 Mhz.
and if i remember well somebody pointed out that i will need an extra clock signal aswell.

I am using Atmega32 , Winavr and ISP with Usbtiny as a programmer and avrdude to connect to MCU

Any help is very much appreciated

Thanks all.

Tags:

AVR Microcontrollers, megaAVR and tinyAVR, ATmega32
Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104798 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Thu. Feb 23, 2012 - 06:41 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

What is wrong with you? This is the second time this week you have created a thread in "Tutorials" that does not belong there. This time I won't offer help and next time I'll just delete the thing. Surely the forum posting rules are clear?

Moderator.

PS Oh well go on then: http://www.engbedded.com/fusecalc/ - that makes avrdude fuse programming almost as easy as using AVR Studio and an Atmel programmer.

Top
Bronze Markbobgardner
bobgardner's picture
Level: 10k+ Postman
Joined: Wed. Sep 4, 2002
Posts: 26609 View posts
Location: Orlando Florida
Posted by bobgardner: Thu. Feb 23, 2012 - 06:47 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Your first message mentions External Oscillator, but then you mention CKOPT, which is used with a crystal, not an oscillator. Oscillators are retangular metal cans as wide as a dip with 4 pins... 5v, gnd, out, and confuse the new guy. Crystals are little cylinders with 2 pins sticking out the bottom. If you really have an oscillator, I think you connect the output to XTAL1.

Imagecraft compiler user

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Fri. Feb 24, 2012 - 02:18 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Sorry Cliff? if i didn't do this knowingly to be honest,
would you show me where is hould have posted it?

sorry everyone for any inconvenience this might have cause
i didn't recall!
could you show me in which forum i should have post it?

Cheers.

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Fri. Feb 24, 2012 - 02:52 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Let me guess,
I should probably have posted it into AVR GCC forum?

Sorry again everybody,
last time i will try ensuring that each of my topic is well posted!
Is it possible to move it into the appropriate forum?

Cheers.

Top
Kartman
Kartman's picture
Level: 10k+ Postman
Joined: Thu. Dec 30, 2004
Posts: 24978 View posts
Location: Melbourne,Australia
Posted by Kartman: Fri. Feb 24, 2012 - 02:56 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

You've been moved here 'avr forum' bro.

As Bob mentions - there is a difference between an oscillator and a crystal. Select 'oscillator' when you want 'crystal' and things wont work.

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Fri. Feb 24, 2012 - 03:55 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@ Kartman & Bob

Sorry for confusion i might have caused, but yes i meant to say an ext Crystal
but since it also oscillates sometimes i like to say it a crystal oscillator no? even datasheet calls it a Crystal Oscillator right? but of course it's not an RC oscillator.
it's confusion how they all are called oscillators, although one is really a crystal and other an RC. but i think a crystal is nothing more than just an RC but wich probably some more acurate ways. anyway

Thank you for moving the post Kartman.
(i have been searching but i couldn't find it! could you let me know which forum did you transfer to?)

Thanks.

Top
ka7ehk
ka7ehk's picture
Level: 10k+ Postman
Joined: Fri. Nov 22, 2002
Posts: 22800 View posts
Location: Tangent, OR, USA
Posted by ka7ehk: Fri. Feb 24, 2012 - 04:06 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

An External Oscillator is a stand-alone clock maker. You apply power and it makes signal. No micro necessary.

Crystal Oscillator uses an amplifier inside the MCU and and external crystal or resonator. Together, the make "oscillator".

If you choose External Oscillator and try to use a crystal, it does not work. The External Oscillator setting turns off one of the oscillator terminals because only one is needed. So, when you try to hook up a crystal, nothing works.

This is a common confusion, but one that you need to figure out.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Fri. Feb 24, 2012 - 03:01 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thank you for your output Jim,

surely i am aware of everything but i probably needed someone to confirm if i am in right track! let's me give you guys a brief of what i will be doing so you could probably point out if something isn't right (I know it's sometimes a hustle to recover the MCU if some of these fuses aren't properly burnt) So:

* I ain't gonna be disabling my JTAG so i will leave JTAGEN still programmed
* Since i want more than 8 Mhz then i will need to set CKOPT at 0, also since i would like to still select the longest delay from start up which is up to 65 ms then i will set SUT[1..0] to 11
* However, I am confused how the table (page 26) works? in facts it doesn't show the range of frequency above 8Mhz?? in steady the next thing it shows is 1<= Could someone make this clear plz? (If i recall correctly Cliff once said something about this table's erroneous??)

* Since Crystal Oscillator Operating Modes makes it clear that when CKOPT is 0 we can choose CKSEL between 101-110-111.
if i then choose it "101" as my CKSEL adding SUT 11 & the rest of BODLEVEL and BODEN unprogrammed (1) then according to FuseCalc. it seems like i will be setting my Low fuse to about 0xFB and High fuse to 0x99 (most importantly on this H fuse ensuring that CKOPT is unprogrammed and JTAGEN programmed)

* So does Lfuse to 0xFB and Hfuse to 0x99 sounds logical guys?

Many Thanks everyone,

Regards.

Top
Bronze Markbobgardner
bobgardner's picture
Level: 10k+ Postman
Joined: Wed. Sep 4, 2002
Posts: 26609 View posts
Location: Orlando Florida
Posted by bobgardner: Fri. Feb 24, 2012 - 05:29 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Use the fuse calculator at engbedded.com

Imagecraft compiler user

Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104798 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Fri. Feb 24, 2012 - 06:05 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:

Use the fuse calculator at engbedded.com

Wish I'd suggested that - oh wait a minute...

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Sat. Feb 25, 2012 - 04:41 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks.
But yeah that's actually where i got the above results (Lfuse to 0xFB and Hfuse to 0x99) from "engbedded.com"

just the last thing which was probably the most important could you help me about the exact arguments i will be typing in the command line in order to set fuses corrects?

I am using Winavr with avrdude and Usbtiny as my programmer.
If i recall correctly someone here once gave an example such as :

" avrdude -c bsd -p m16 -P lpt1 -U lfuse:w:0xEF:m -U hfuse:w:0xC9:m "

and added that:

* bsd : was the programmer he's been using. which in my case is usbtiny
* lpt1: was also his port. which in my case is usb.

So can I go ahead and use this argument to burn Lfuse to 0xFB and Hfuse to 0x99 accordingly?

" avrdude -c usbtiny -p m32 -P usb -U lfuse:w:0xFB:m -U hfuse:w:0x99:m "

Please help me as i am unsure,

Thank you all.

Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104798 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Sat. Feb 25, 2012 - 09:03 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Google says (for example):

http://blog.spitzenpfeil.org/wor...

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Sat. Feb 25, 2012 - 12:25 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thank you Cliff :)

I have been googling but i didn't come across your suggested link.
Well... It looks like i were in the right track as both arguments (the one from the site suggests and the other i wrote earlier looks almost the same except some other little modifications)

* The one from " http://blog.spitzenpfeil.org/wor... ... spavrdude/" is

"avrdude -p usbtiny -c m168 -e -u -U lock:w:0x3f:m -U efuse:w:0x00:m -U hfuse:w:0xDD:m -U lfuse:w:0xFF:m"

I just noticed that in this one there were some little modifications as the avrdude - help says that: "-e" performs a chip erase & "-u" disables safemode.
the confusion in the above argument it doesn't shows the type of port that's been used!! this is being specified by "-P" right?

* So If i were to interpret what the user was trying to do i would say that he was
trying to burn his mega168 to lfuse 0xFF, hfuse 0xDD & efuse 0x00. using Usbtiny as programmer but the port then?? (isn't it necessary?)

* To me without the need of erasing the chip or disabling the safe mode
the argument

" avrdude -p usbtiny -c m32 -U hfuse:w:0x99:m -U lfuse:w:0xFB:m" still look alright!

Could someone point out if I am missing anything.

(I have been asking many questions about this! and i will really be regretting alot if something isn't right afterall :( I really won't be having time applying other external clock or High voltage programming to recover the MCU back. I just can't afford that time)

Thank you all for your contribution in helping me out.

Regards.

Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104798 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Sat. Feb 25, 2012 - 02:04 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:

I just noticed that in this one there were some little modifications as the avrdude - help says that: "-e" performs a chip erase & "-u" disables safemode.
the confusion in the above argument it doesn't shows the type of port that's been used!! this is being specified by "-P" right?

That's because you don't need -P when using usbtiny - it doesn't have a choice it's always on "usb" so no need to say (though I think it's benign if you want to include "-P usb")
Quote:

but the port then?? (isn't it necessary?)

No, isn't necessary.

If you have an "accident" I have an article in Tutorial Forum about recovering a "locked out" AVR

Top
Kase57
Kase57's picture
Level: Hangaround
Joined: Sat. Jan 14, 2012
Posts: 133 View posts
Location: New Zealand
Posted by Kase57: Sat. Feb 25, 2012 - 02:15 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thank you Cliff.

Really appreciating all the efforts and times
you put in answering others questions

Just to confirm lastly that all these will need to happen
having already a 16 Mhz crystal (with 2x 22pF caps) connected to the MCU?

Thanks again.

Top
Bronze Markbobgardner
bobgardner's picture
Level: 10k+ Postman
Joined: Wed. Sep 4, 2002
Posts: 26609 View posts
Location: Orlando Florida
Posted by bobgardner: Sat. Feb 25, 2012 - 05:29 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

So after this robust compare and contrast discussion of oscillators and crytals, has anyone mentioned what type of AVR is being programmed or did I miss it? Or does it matter?

Imagecraft compiler user

Top
ka7ehk
ka7ehk's picture
Level: 10k+ Postman
Joined: Fri. Nov 22, 2002
Posts: 22800 View posts
Location: Tangent, OR, USA
Posted by ka7ehk: Sat. Feb 25, 2012 - 05:49 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Processor type does not matter with respect to the difference between "crystal" and "external oscillator". The precise fuses may vary, but the phenomenon of the crystal not operating if you choose "external oscillator: does not vary. AFAIK

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

Top