AVR Freaks

AVR forum :: RE: Interrupt vector table in atmega168

Author: theusch
Subject: RE: Re: Interrupt vector table in atmega168
Posted: May 09, 2008 - 11:30 AM (GMT -5)
Topic Replies: 9

It looks like Peter likes to make things modular, and puts the vector with the handler in the source. This makes a lot of sense especially if you make your projects modular and multi-file--quite elegant.

But I've never been described as "elegant". So I like to put my vector table right at the head of the code, and usually only have a single file or a few files anyway using Atmel's assembler. But in any case, take the bit of extra time to make a vector table with .ORGs for each. Then decide how to handle the "thunks"--interrupts that fire with no ISR. But it will save you from worrying about missing one and the width problem that you ran into, especially if you want to flip around in the '48/'88/'168/'328 family.

Code:

(a fragment from the chip include file)

; ***** INTERRUPT VECTORS ************************************************

.equ   INT0addr   = 0x0002   ; External Interrupt Request 0

.equ   INT1addr   = 0x0004   ; External Interrupt Request 1

.equ   PCI0addr   = 0x0006   ; Pin Change Interrupt Request 0

...

.CSEG

.ORG 0

   ; ADD RESET VECTOR JUMP HERE

.ORG   INT0addr   ; External Interrupt Request 0

.ORG   INT1addr   ; External Interrupt Request 1

.ORG   PCI0addr   ; Pin Change Interrupt Request 0

...

Off-topic forum :: RE: Don't you hate it...

Author: Plons
Posted: May 09, 2008 - 11:28 AM (GMT -5)
Topic Replies: 7

It hurts. That's for sure. It's a hard job ..... education modules/PNphpBB2/images/smiles/icon_wink.gif" alt="Wink" border="0" />

JJ, I pm'd as well (in dutch)

Nard
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General Electronics :: RE: voltage ruducer requirment, but only when less then 1V

Author: djoshi
Posted: May 09, 2008 - 11:27 AM (GMT -5)
Topic Replies: 11

The datasheet anit availble on the net or not that i am aware of the , data sheet says DC, rather then any current rates. But a similar device has mentioned that it is about 300mA.

AVR32 Hardware :: RE: LCD pins on AP7002

Author: UNiXWHoRe
Subject: RE: LCD pins on AP7002
Posted: May 09, 2008 - 11:22 AM (GMT -5)
Topic Replies: 4

Thank you hce, thats what I thought... The only thing left to figure out for the TFT is the usage of LCD pin DISP, which the datasheet says is "Display On/Off". what is the general convention as to how to use this pin? Should I tie it to an AVR32 pin and have the LCD driver enable it, or is it safe to just use a pullup to 3.3v on it? My application will require the LCD always anyways...

Off-topic forum :: RE: Can we finally close the book on global warming?

Author: cpluscon
Subject: RE: Re: RE: Re: RE: Can we finally close the book on global
Posted: May 09, 2008 - 11:11 AM (GMT -5)
Topic Replies: 17

The source cited by foxnews is the Houston Chronicle:
http://www.chron.com/disp/story.mpl/hur ... 36103.html

Quoting Gray the author wrote:

"You see, so many people in our department make a living off the global warming threat..."

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AVR forum :: RE: Choosing a microcontroller

Author: theusch
Posted: May 09, 2008 - 11:09 AM (GMT -5)
Topic Replies: 10

Quote:

164P has now really superceded the 162 and is better in just about every way.

??? That is kind of apples and oranges. Yes, they are both 40/44 pin packages. But one is the '8535 family w/ ADC, and the other is '8515 family w/ no ADC but external memory interface. I'm trying to think of what you meant. Mega16? '169 and '165 are 64-pin. And yes the combination of features does come together with the '128 family with the Mega64 being the lowest-priced entry point right?

[It will be quite interesting to see what the street prices of the Xmegas will be when they are finally stocked. The prices that have been tossed about might indicate that even the first A1 "big" family may actually be less expensive than a Mega64 or Mega128.]

Aaah, I get a bit more now that I noticed Jim's reference:

Quote:

As far as a good all around micro, look at the mega 162.

I'd pick the Mega88 family as "general purpose" if the pin count is sufficient. It has all the AVR subsystems available except the external memory interface, and some of the specialty features such as high-speed PWM. No onboard temperature sensor or differential A/D or A/D gain. But then, as mentioned, the '164 is a fine choice and less expensive than '16.

Perhaps you do a lot of external memory apps, Jim, and not much A/D? In over 100 production apps I've only done external memory once, and A/D is used on nearly all. It sounds like we may live in different app worlds.

Lee

Off-topic forum :: RE: Need help to translate peace of code to C#

Author: cpluscon
Subject: RE: ----
Posted: May 09, 2008 - 11:05 AM (GMT -5)
Topic Replies: 11

We used pointers to process large arrays (of pixels) in tight little loops and resulted in considerable performance improvement. As Smiley alludes, widespread use of pointers in C# suggests a lack of knowledge about the language/environment. IME, the runtime exhibits impressive performance in most cases.

The code presented by the OP is replete with opportunity for optimization, so perhaps he should pursue that route as well. Pointers may not be needed....
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AVR forum :: Hardware Partioning the AT90USBKEY's memories

Author: mikeboro
Subject: Hardware Partioning the AT90USBKEY's memories
Posted: May 09, 2008 - 10:57 AM (GMT -5)
Topic Replies: 0

I am attempting to create a demo with the AT90USBKEY which will provide access to user either flash memory i.e. the user will select if they wish to see DF 0, or DF1 (or possible DF0 and DF1 as two partitions/drives).

Does anyone have any suggestions on the best approach to doing this?
i.e.
Should I create 3 configurations (1 control and 2 separate mass storage implementations)
or
Is there a way I can handle it with just 2 configs (1 control and 1 mass storage).
or
Is there an easier way?

All the Best,
Mike

AVR forum :: RE: AT90usb647 Atmel bootloader strange bootsize

Author: curtvm
Subject: RE: AT90usb647 Atmel bootloader strange bootsize
Posted: May 09, 2008 - 10:57 AM (GMT -5)
Topic Replies: 1

I would read the fuses and figure out what bootsz0/1 actually are (in case the programmer is not doing the bits correctly). 0x7800 is the 'default' boot address according to the datasheet, bootsz=01 (which is unusual in that its not using the max size, but that matches the dfu bootloader hex file).

AVR forum :: RE: Bug in Atmega8.Help me plz!!!!!!!!!!!!!!!!!

Author: Koshchi
Subject: RE: Bug in Atmega8.Help me plz!!!!!!!!!!!!!!!!!
Posted: May 09, 2008 - 10:47 AM (GMT -5)
Topic Replies: 4

The first thing that I would do is rewrite the code to not use goto. goto is never necessary and almost never the best way to do something.
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Steve A.

The Board helps those that help themselves.

General Electronics :: RE: Inductor ripple current

Author: incal99
Posted: May 09, 2008 - 10:46 AM (GMT -5)
Topic Replies: 16

Ossi ,This is a 12,5Khzx2=25 Khz standard converter. apprx: 8KW/liter.

I am trying to achieve 60Khzx2=120Khz , to fullfill the 35KW/liter requirement.
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We dream of a world where current does not need the voltage to flow.

AVR forum :: RE: ATMEGA1281 RTC + SLEEP problems...

Author: xothar
Subject: RE: ATMEGA1281 RTC + SLEEP problems...
Posted: May 09, 2008 - 10:45 AM (GMT -5)
Topic Replies: 7

Long time has passed and i forgot to tell U that the problem was solved....
Problem located on 32Khz Xtal's Caps.

Thank you all.

AVR forum :: RE: An LCD for the STK500

Author: Koshchi
Subject: RE: An LCD for the STK500
Posted: May 09, 2008 - 10:37 AM (GMT -5)
Topic Replies: 3

You could use a Butterfly. It has the advantage of being easily useable out of the box. Just put it in the correct mode and send text to it through RS232. It has the disadvantage of having only 6 visible characters, so longer messages must scroll (which it can do automatically).
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Regards,
Steve A.

The Board helps those that help themselves.

AVR forum :: RE: DMX receiver int not being entered

Author: glitch
Posted: May 09, 2008 - 10:36 AM (GMT -5)
Topic Replies: 8

ok, but in your main loop you set it back to zero. So even if it did turn on, it would turn off so quickly you would never see it.

as for the names... did you actually look at the headerfile for the bitnames?

The correct names are
URSEL1
USBS1
UCSZ10

General Electronics :: RE: Please contribute PCB layout pointers

Author: barney_1
Subject: Re: RE: Re: RE: Please contribute PCB layout pointers
Posted: May 09, 2008 - 10:35 AM (GMT -5)
Topic Replies: 27

dl8dtl wrote:

You still neglected to connect AGND and AVcc. Don't do this, you are risking to kill
your ATmega8. At the minimum, your port C will be rendered unusable because that port's
IO stages are powered by AVcc.

Hey, there it is plain as day in the datasheet:

Quote:

AVCC is the supply voltage pin for the A/D Converter, Port C (3..0), and ADC (7..6). It should be
externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be con-
nected to VCC through a low-pass filter. Note that Port C (5..4) use digital supply voltage, VCC.

Thanks for pointing that out for me J�rg (sorry you had to say it twice). I completely missed that part of the the datasheet and it would definitely have caused me problems!

I've revised the schematic and the board to reflect this. Surprisingly, after I had routed the +5 signal on the schematic Eagle didn't put an unrouted signal from the AVcc to the +5 rail. It even causes an error when I run this track using the "wire" tool. Anyone else had this problem before?