| Author |
Message |
|
|
 Posted: Oct 29, 2008 - 07:58 AM |
|
Joined: Aug 14, 2008
Posts: 5
|
|
|
|
|
|
|
|
Posted: Oct 29, 2008 - 08:01 AM |
|
Joined: Oct 27, 2008
Posts: 171
|
|
I don't have an atmega16 but can't you check what it is set at with AVR Studio?
Go to Tools -> Program AVR -> Auto Connect -> Fuse tab -> and look at what SUT_CKSEL is set at. |
|
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 08:40 AM |
|
Joined: Mar 28, 2001
Posts: 20390
Location: Sydney, Australia (Gum trees, Koalas and Kangaroos, No Edelweiss)
|
|
| 1MHz as they come from the factory, ALL mega and tiny types. (8MHz internal oscillator with the DIV8 fuse set) |
_________________
John Samperi
Ampertronics Pty. Ltd.
www.ampertronics.com.au
* Electronic Design * Custom Products * Contract Assembly
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 10:17 AM |
|
Joined: Jul 18, 2005
Posts: 62354
Location: (using avr-gcc in) Finchingfield, Essex, England
|
|
Actually the mega16 doesn't have a CKDIV8 fuse. It's one of the old school with separate 1/2/4/8MHz internal RC oscillators with the 1MHz one selected by default.
OP should be warned that it's not EXACTLY 1MHz, it's +/-10% of that. |
_________________
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 02:38 PM |
|
Joined: Nov 17, 2004
Posts: 13849
Location: Vancouver, BC
|
|
|
Quote:
1MHz as they come from the factory, ALL mega and tiny types
Not quite true. There are a couple that have default frequencies other than 1MHz (and a couple of older ones that don't have an internal oscillator at all). |
_________________
Regards,
Steve A.
The Board helps those that help themselves.
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 03:25 PM |
|
Joined: Feb 19, 2001
Posts: 25923
Location: Wisconsin USA
|
|
|
Quote:
There are a couple that have default frequencies other than 1MHz (and a couple of older ones that don't have an internal oscillator at all).
OK, I'll bite.  As a trivia discussion you must have had one or more models in mind.
I thought maybe Mega406 or AT90PWMn would be the oddballs, but nope--1MHz.
Yes, classic AT90S did not have internal oscillators. But they ain't around anymore.
So, what model(s) qualify to be included in your two categories?
Lee |
|
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 03:38 PM |
|
Joined: Jul 18, 2005
Posts: 62354
Location: (using avr-gcc in) Finchingfield, Essex, England
|
|
Isn't there a Tiny that has 4.8 / 9.6 options and defaults to one of those?
(might be one intended for IR use?) |
_________________
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 04:26 PM |
|
Joined: Dec 08, 2004
Posts: 4719
Location: Nova Scotia, Canada
|
|
|
clawson wrote:
Isn't there a Tiny that has 4.8 / 9.6 options and defaults to one of those?
(might be one intended for IR use?)
It's the ATtiny13 and its replacement the ATtiny13A. It offers a choice of a 4.8 MHz, a 9.6 MHz, and a 128 kHz internal oscillator. Alternatively an external clock (not crystal) can be used.
It comes up by default with the 9.6 MHz oscillator selected and the CKDIV8 fuse programmed, to result in an overall default frequency of 1.2 MHz. |
|
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 04:32 PM |
|
Joined: Nov 17, 2004
Posts: 13849
Location: Vancouver, BC
|
|
| The tiny28 also has a 1.2MHz default clock. |
_________________
Regards,
Steve A.
The Board helps those that help themselves.
|
| |
|
|
|
|
|
|
Posted: Oct 29, 2008 - 05:08 PM |
|
Joined: Feb 19, 2001
Posts: 25923
Location: Wisconsin USA
|
|
|
Quote:
It's the ATtiny13 and its replacement the ATtiny13A.
Quote:
The tiny28 also has a 1.2MHz default clock.
LOL, a tempest in a teapot.
1.2MHz +/- 10% = 1.08-1.32MHz
1.0MHz +/- 10% = 0.90-1.10MHz
So I don't think I'd call them exceptions to the "rule". [Note the Tiny13 datasheet has many characteristics specified for 1MHz.]
For the topic "what is the default frequency" then I have no objections to your better knowledge of AVR trivia than I do.
For the "inquiring minds want to know" followup: Is it important except for ISP? In any of the above cases ISP frequency should still be 250kHz or lower.
Lee |
|
|
| |
|
|
|
|
|
FAQ
Search
Register
Log in to check your private messages
Log in
Maximize
RSS
