AVR-Chat

Thank you everyone for your responses.  As it happens I have a 10mhz crystal across 4 and 5 on the PCB already, with attendant 18pf caps to GND.  I'm going to remove the crystal and try the AVRDUDE command line fix, that looks like the best at this point.  If that doesn't work, I'll try the signal injector.  Thanks again, and have a great day.

Say, the cause of this whole nightmare was my attempt at getting an LCD working correctly from the 2313.  Sadly though, when I plug in the LCD I just get the first line showing as a set of 16 black squares.  

My connections are RS @PB2, E @ PB3, DB4 @ PB4, DB5 @ PB5, etc.  I'm using Bascom to program and I've used the Config LCDPIN statement to set up how the LCD is connected, but I get the dark line stuff right from the start, even before I programmed the chip, so I suspect there's something else afoot here.  GND is connected, VCC is 5v,  contrast runs to a 2.2K to GND.  Pin 5 to GND.  

Any thoughts on where to look here. Oh yes, the LCD is a 5v 44780 standard 16x2 LCD with a 5v contrast.

Mark Weston
 		
---------------------------------
Now you can have a huge leap forward in email: get the new Yahoo! Mail. 

[Non-text portions of this message have been removed]

On 2/14/07, Mark Weston <weston54@yahoo.com> wrote:
>
> Thank you everyone for your responses.  As it happens I have a 10mhz
> crystal across 4 and 5 on the PCB already, with attendant 18pf caps to
> GND.  I'm going to remove the crystal and try the AVRDUDE command line fix,
> that looks like the best at this point.  If that doesn't work, I'll try the
> signal injector.  Thanks again, and have a great day.


You have a 10pF crystal?     If your crystal is specified for 18pF Cl, then
you should probably be using 33pF caps.


[Non-text portions of this message have been removed]

33pf caps??  The crystal is 10mhz, and stamped right on the package
from Digikey is that it's rated for 18pf caps.  I'm not sure I
understand why you recommend 33pf caps.

Mark Weston

----- Original Message ----- 

From: "weston54" <weston54@yahoo.com>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, February 14, 2007 3:52 PM
Subject: [AVR-Chat] Re:Tiny2313


> 33pf caps??  The crystal is 10mhz, and stamped right on the package
> from Digikey is that it's rated for 18pf caps.  I'm not sure I
> understand why you recommend 33pf caps.

That is the load capacitance to get the marked frequency, not the value for 
the feedback capacitors.

The capacitors are effectively in series, so you halve the value: 33/2 = 
16.5 pF, plus 1.5 for stray capacitance gives 18 pF.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@btinternet.com
http://www.geocities.com/leon_heller

On Wed, Feb 14, 2007 at 09:04:51AM -0500, Mark Weston wrote:
> 
> Say, the cause of this whole nightmare was my attempt at getting an
> LCD working correctly from the 2313.  Sadly though, when I plug in the
> LCD I just get the first line showing as a set of 16 black squares.  

Thats what most do fresh out of powerup.

-- 
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.

Also, you should have a pot in your circuit to adjust the intensity 
("brightness", sort of) on your display.  When this pot is advanced too 
far, the display characters all show up as black boxes.

Zack

On Wed, 14 Feb 2007, David Kelly wrote:

> On Wed, Feb 14, 2007 at 09:04:51AM -0500, Mark Weston wrote:
> > 
> > Say, the cause of this whole nightmare was my attempt at getting an
> > LCD working correctly from the 2313.  Sadly though, when I plug in the
> > LCD I just get the first line showing as a set of 16 black squares.  
> 
> Thats what most do fresh out of powerup.
> 
>

On 2/14/07, weston54 <weston54@yahoo.com> wrote:
>
> 33pf caps??  The crystal is 10mhz, and stamped right on the package
> from Digikey is that it's rated for 18pf caps.  I'm not sure I
> understand why you recommend 33pf caps.


Sigh..

The Cl value is NOT the size of caps to use.
See app notes at FOX crystal, they are probably the most easy to understand
that I've seen.

The crystal sees the loading caps as being in series, so the proper way to
size the caps is to assume maybe 5pF for stray capacitance, and since the
caps are equal value you can simplify the parallel capacitor equation to
twice the desired value, so (18*2) = 36, - 5 = 31.  Closest standard value
is 33pF.


[Non-text portions of this message have been removed]

99% of the time you can just hang a 1K resistor to ground off of the bias
pin and get a perfectly fine display.

DLC
--
Dennis Clark dlc@frii.com
www.techtoystoday.com

> Also, you should have a pot in your circuit to adjust the intensity
> ("brightness", sort of) on your display.  When this pot is advanced too
> far, the display characters all show up as black boxes.
>
> Zack
>
> On Wed, 14 Feb 2007, David Kelly wrote:
>
>> On Wed, Feb 14, 2007 at 09:04:51AM -0500, Mark Weston wrote:
>> >
>> > Say, the cause of this whole nightmare was my attempt at getting an
>> > LCD working correctly from the 2313.  Sadly though, when I plug in the
>> > LCD I just get the first line showing as a set of 16 black squares.
>>
>> Thats what most do fresh out of powerup.
>>
>>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

Because the caps are, in essence, in series with each other, and so 
two 33 pF caps in series is equivalent to a 16.5 pF cap in parallel with 
the crystal.

tom

weston54 wrote:

>
> 33pf caps?? The crystal is 10mhz, and stamped right on the package
> from Digikey is that it's rated for 18pf caps. I'm not sure I
> understand why you recommend 33pf caps.
>

Hi Mark,

Many may have suggested this to you, but your display is probably
working fine, just way too much contrast. Made the same mistake when I
used my first LCD module many years ago. Put a 10k pot between Vcc and
GND with the output going to the contrast pin, and adjust until you
see text. Contrast pin is usually pin #3 on most LCD modules.

Cheers
Hein B
Auckland, New Zealand.

--- In AVR-Chat@yahoogroups.com, Mark Weston <weston54@...> wrote:
>
> Thank you everyone for your responses.  As it happens I have a 10mhz
crystal across 4 and 5 on the PCB already, with attendant 18pf caps to
GND.  I'm going to remove the crystal and try the AVRDUDE command line
fix, that looks like the best at this point.  If that doesn't work,
I'll try the signal injector.  Thanks again, and have a great day.
> 
> Say, the cause of this whole nightmare was my attempt at getting an
LCD working correctly from the 2313.  Sadly though, when I plug in the
LCD I just get the first line showing as a set of 16 black squares.  
> 
> My connections are RS @PB2, E @ PB3, DB4 @ PB4, DB5 @ PB5, etc.  I'm
using Bascom to program and I've used the Config LCDPIN statement to
set up how the LCD is connected, but I get the dark line stuff right
from the start, even before I programmed the chip, so I suspect
there's something else afoot here.  GND is connected, VCC is 5v, 
contrast runs to a 2.2K to GND.  Pin 5 to GND.  
> 
> Any thoughts on where to look here. Oh yes, the LCD is a 5v 44780
standard 16x2 LCD with a 5v contrast.

> 
> Mark Weston
>  		
> ---------------------------------
> Now you can have a huge leap forward in email: get the new Yahoo! Mail. 
> 
> [Non-text portions of this message have been removed]
>

On Feb 15, 2007, at 3:59 PM, kernels_nz wrote:

> Hi Mark,
>
> Many may have suggested this to you, but your display is probably
> working fine, just way too much contrast. Made the same mistake when I
> used my first LCD module many years ago. Put a 10k pot between Vcc and
> GND with the output going to the contrast pin, and adjust until you
> see text. Contrast pin is usually pin #3 on most LCD modules.

IIRC when top line is dark and bottom is not the controller has not  
been initialized.

If it was only a matter of contrast then both top and bottom would be  
equally dark.

When the Hitachi controller powers up it drives all the pixels in the  
top line until its initialized in the 2 line mode.

--
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.

Mark,
I have used BASCOM with great success when dealing with LCD's! Sounds
like you missed something when setting up the stuff. Try to modify the
sample file for LCD i.e. lcd4.bas!

The simulator is pretty nifty, and do test the code there first! Once
you have the LCD working in simulator mode, remove the $sim switch and
compile the code again (very easy to forget) and if you have it wired
ok, it will work..... or should work!

You might find good help at the BASCOM forum (http://www.mcselec.com),
ppl here seems more into C and assembler.

Cheers
Lasse

--- In AVR-Chat@yahoogroups.com, Mark Weston <weston54@...> wrote:
>
> Thank you everyone for your responses.  As it happens I have a 10mhz
crystal across 4 and 5 on the PCB already, with attendant 18pf caps to
GND.  I'm going to remove the crystal and try the AVRDUDE command line
fix, that looks like the best at this point.  If that doesn't work,
I'll try the signal injector.  Thanks again, and have a great day.
> 
> Say, the cause of this whole nightmare was my attempt at getting an
LCD working correctly from the 2313.  Sadly though, when I plug in the
LCD I just get the first line showing as a set of 16 black squares.  
> 
> My connections are RS @PB2, E @ PB3, DB4 @ PB4, DB5 @ PB5, etc.  I'm
using Bascom to program and I've used the Config LCDPIN statement to
set up how the LCD is connected, but I get the dark line stuff right
from the start, even before I programmed the chip, so I suspect
there's something else afoot here.  GND is connected, VCC is 5v, 
contrast runs to a 2.2K to GND.  Pin 5 to GND.  
> 
> Any thoughts on where to look here. Oh yes, the LCD is a 5v 44780
standard 16x2 LCD with a 5v contrast.

> 
> Mark Weston
>  		
> ---------------------------------
> Now you can have a huge leap forward in email: get the new Yahoo! Mail. 
> 
> [Non-text portions of this message have been removed]
>