Forum Index > Projects > Larson Scanner kit and LED Menorah kit support
 crystal/cap values?
 |  Printable Version
By: Anonymous: gobo () on Sunday, October 25 2009 @ 11:01 AM PDT (Read 2287 times)  
Anonymous: gobo

If one were wanting to experiment with the serial interface and ftdi cable, what are the suggested crystal and cap values? The datasheet offers a number of values with differing serial error rates.

OR, at slow speeds like 2400 baud, is the internal clock good enough?





       
   
By: Windell (offline) on Sunday, October 25 2009 @ 12:22 PM PDT  
Windell

One thing to be sure and note is that the Larson Scanner uses the low-power version, the ATtiny2313V, so that it can keep working even when the voltage falls very low. The ATtiny2313V is limited to 10 MHz, so if you do use a crystal and cap (or ceramic resonator) don't try the 16 MHz one.

8 MHz is a popular choice for these chips.

Now, I do have reason to suspect that the AVR internal oscillator is sufficient for basic serial communication. The original Lilypad Arduino used the internal oscillator, set to 8 MHz, for operation, and supported serial programming, so it's certainly worth trying... and it's likely that you'll succeed if your clock rate is low enough. (The internal oscillator is set to 512 kHz in the default program-- you'll almost certainly want to change that.)

Also, as hinted at in this discussion, you might even consider mucking with the clock calibration bits to achieve slightly better accuracy.


Windell H. Oskay
drwho(at)evilmadscientist.com
http://www.evilmadscientist.com/

Forum Evil Scientist
Evil Scientist

Status: offline

Registered: 06/15/06
Posts: 1932
Sunnyvale, CA

Profile Email Website  
   
By: Anonymous: gobo () on Sunday, October 25 2009 @ 03:01 PM PDT  
Anonymous: gobo

Glad you pointed out that the supplied chip is the V version, I had over looked that. The two xtal choices seem to be 3.6864 and 11.059.





       
   
By: Windell (offline) on Sunday, October 25 2009 @ 05:55 PM PDT  
Windell

I'd suggest a FOXSLF/080-20 crystal, with two 18pf - 20 pf caps.


Windell H. Oskay
drwho(at)evilmadscientist.com
http://www.evilmadscientist.com/

Forum Evil Scientist
Evil Scientist

Status: offline

Registered: 06/15/06
Posts: 1932
Sunnyvale, CA

Profile Email Website  
   



 All times are PDT. The time is now 09:56 PM.
Normal Topic Normal Topic
Locked Topic Locked Topic
Sticky Topic Sticky Topic
New Post New Post
Sticky Topic W/ New Post Sticky Topic W/ New Post
Locked Topic W/ New Post Locked Topic W/ New Post
View Anonymous Posts 
Able to Post 
Filtered HTML Allowed 
Censored Content 

Evil Mad Scientist Forum Archives — Read only!

Please visit our new forums for new discussions.


DIY Hardware for Electronic Art


The Original Egg-Bot Kit


Octolively
Interactive LED kits


Meggy Jr RGB
LED matrix game
development kit.


Business-card sized
AVR target boards


Peggy 2
LED Pegboard kits

My Account






Lost your password?