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Topic: Basic 664p/1284p board (Read 2936 times) previous topic - next topic

mmcp42

crikey
you kind of assume that basic parts will work correctly!

glad you got it sorted
but I bet you are VERY glad!
there are only 10 types of people
them that understands binary
and them that doesn't

cowasaki


crikey
you kind of assume that basic parts will work correctly!

glad you got it sorted
but I bet you are VERY glad!


Well yes!

The crystal and caps that were on the board had come off a working 328p breadboard!
I made a second board using point to point soldering and with it's own set of components.
I made a third board again with breadboard.

ALL three had the same issue!

The crystals came from 3 different suppliers. CPC, Farnell and Ebay
The crystals were 3 different brands
The caps came from 2 suppliers.

I am absolutely positive that it was wired correctly....

ie..  Crystal as close as possible to the chip on the XTAL lines then each XTAL line connected to GND via a 22pF capacitor.


So no idea why it wouldn't work

Anyway now that it is working I get to play with the PCB making kit that I bought last month and have still not used yet.

First job is trying to work out in Eagle how to print the two solder layers !! (If it all goes to plan I'll send you a board and a 1284p)

mmcp42


First job is trying to work out in Eagle how to print the two solder layers !!

hint - click the layers icon and just select the layer you want to print


(If it all goes to plan I'll send you a board and a 1284p)

:) grinsalot
there are only 10 types of people
them that understands binary
and them that doesn't

CrossRoads

Cowasaki, you are in England?

Odd that you are having so many issues with such basic parts.
I have built up numerous 328 based boards on wirewrap sockets with 16 MHz and two 22 pf caps without any problems.
Perhaps it is power supply related?
Do you have 100nF caps on the VCC and AVCC lines?
Where is your power coming from?
I have 12V switching regulator wallwarts going thru a 7805 in some cases (need 12V for strings of LEDs that arduino controls via transistor) and 5V switching regulator wallwart with a 12V boost converter in other cases.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

skyjumper

Listen to Crossroads, he knows the hardware very well.

On a tangentially related topic, a few days ago I did discover an issue with the bootloader I sent you guys. I knew it was not causing the problem discussed here so i didn't mention it so as not to confuse the issue. Anyhow, apparently on sketches larger than 64K compiled, the upload via Avrdude does fail. I can put the hex file into the mpu via AVR Studio, so its not the hardware. Anyhow I am working on it, I'll supply you both with a working bootloader soon.

PS - My boards are in! In Cranstopn :-( I gotta go fetch them today.



CrossRoads

We have a Customs office in Cranston? Or did DHL/Fedex/etc misdeliver?
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

skyjumper

The vendor shipped to my billing address by mistake.

cowasaki


Listen to Crossroads, he knows the hardware very well.



Yes. I realised that from seeing some of his other posts.

I was powering it from the 5v of the duemilanove board OR the FTDI cable.

I had decoupling caps and had tried with and without a couple of electrolitics.

I was using the same setup with a 328p which was working perfectly using the same caps and crystal!

The only changes I made when I went to the ceramic oscillator was to pull out the caps and crystal, install the ceramic osc just below the 1284p and use 3 jump wires to connect it. I then tan the IDE and it worked straight off. Like I said, very strange! The board was even tried with 3 different
Computers so it can't even be a bad USB power line on a particular machine. I'm at a loss as the what it is.

cowasaki


Anyhow I am working on it, I'll supply you both with a working bootloader soon.


Cheers you are a star.  Can you do 16 and 20MHz versions?  Is there a reason why the upload speed is 38400?  It's not a problem, just wondering.

retrolefty

Quote
I was using the same setup with a 328p which was working perfectly using the same caps and crystal!

The only changes I made when I went to the ceramic oscillator was to pull out the caps and crystal, install the ceramic osc just below the 1284p and use 3 jump wires to connect it. I then tan the IDE and it worked straight off. Like I said, very strange! The board was even tried with 3 different
Computers so it can't even be a bad USB power line on a particular machine. I'm at a loss as the what it is.



Just a small clarification on your choice of names for the various clock components you have talked about in this thread.

First off a complete clock oscillator requires both a resonator element (determines it's operating frequency) and a amplification circuit (ensures it starts up and oscillates continuously). A AVR chip has the clock oscillator amplification circuit built-in to the chip, so most AVR projects use only a crystal resonator or a ceramic resonator. What sometime gets confused is that there are avalible complete external crystal oscillator chips that include the crystal resonator and amplification circuit all in one package. These small DIP (normal 4 pin) package output a TTL clock signal all by themselves. A AVR with proper fuse settings can utilize such a crystal oscillator, but normally the lower cost crystal resonator or ceramic resonator, or even the internal R/C clock is used because of lower costs. However if one wanted the most accurate clock source, one might choose an external crystal oscillator, perhaps a temperature compensated or oven controlled version.

Crystal resonator: Has only two terminals, requires two padding caps:  http://www.sparkfun.com/products/536

Ceramic resonator: has three terminals, center terminal grounded, internal caps: http://www.sparkfun.com/products/9420

Crystal oscillator: Complete standalone crystal controlled oscillator, requires a Vcc voltage and ground and has a signal output pin.:    http://www.b2bcrystaloscillator.com/dip-crystal-osciallator.htm

So this semi-rant isn't really aimed at you specifically, but I find the term crystal and crystal oscillator used around here synonymously, when they they are two different things. Just thought I would throw this out for newcomers to help with the component names we utilize in arduino projects.

Lefty

CrossRoads

The resellers are no better :)
"Crystal 16MHz
sku: COM-00536
Description: Standard frequency crystals - use these crystals to provide a clock input to your microprocessor. Rated at 20pF capacitance and +/- 50ppm stability. Low profile HC49/US Package."

I believe we are all referring to the same thing.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

retrolefty

Quote
I believe we are all referring to the same thing.


Of that I'm sure.

But there have been posting made by several newcomers at times, that were attempting to build stand-alone 328p circuits and ordered a 16Mhz crystal oscillator and didn't receive the simple two terminal component they were expecting to. So I've tried to help with that terminology when I see it.  ;)


Lefty


CrossRoads

Yeah, ya gotta look at datasheet, or at least the picture!, when ordering.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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