electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time

poster

Please visit the chat
 Forum index » DIY Hardware and Software » Circuit Bending
replacing crystal with oscillator
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 1 of 1 [8 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
stolenfat



Joined: Apr 17, 2008
Posts: 472
Location: Sunny Oakland California
Audio files: 1

PostPosted: Wed May 02, 2018 6:53 pm    Post subject: replacing crystal with oscillator Reply with quote  Mark this post and the followings unread

Standard bending technique... replacing the 8mhz crystal with a square wave on a yamaha keyboard.

Rigged up a 40106 to replace a crystal but I can't seem to get the output hz high enough to match the 8mhz crystal.

.1 uf got me some where fun... but crashes the cpu
.001 uf gets me even better results but not quite there... so i kept trying smaller and smaller capacitors.

1pf is the smallest I have, and I guess from some research thats about as small as it gets. the 1pf actually does get the cpu clocking well but it's at a notably slower clock speed as the sounds it produces seem 'bit reduced' from the slower clock speed.

is there a circuit out there I could use to create an 8mhz squarewave? I know that's incredibly high.

_________________
home made noise and electronic ill-logic
Back to top
View user's profile Send private message Visit poster's website
Grumble



Joined: Nov 23, 2015
Posts: 755
Location: Netherlands
Audio files: 23

PostPosted: Wed May 02, 2018 9:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

http://www.ti.com/lit/ds/symlink/cd40106b.pdf

the 40106 just isnt fast enough.
how i would do this is described here: http://electro-music.com/forum/topic-69874.html
but you need an arduino for it....

_________________
my synth
Back to top
View user's profile Send private message Visit poster's website
stolenfat



Joined: Apr 17, 2008
Posts: 472
Location: Sunny Oakland California
Audio files: 1

PostPosted: Wed May 02, 2018 10:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

Arduino you say? Hmm! I just happen to have some laying around. Didn't even consider.

(BTW, Your keen advice has been very helpful lately. Ty buddy)


Alright... I'm still new to coding but I'd imagine I could find a way to get the chip to vary a clock pulse speed while checking an analog value.

Something like...

Set a pin to out put a clock at speed x
Set a pin to check an analog value
If that value is at 100 Percent, 5v, then put out 8mhz
When the analog value drops lower the clock speed and limit it to 4mhz or something.

Possibly check another pin with a switch to change the lowest possible clock speed.

Edit: some googling before bed leads me to believe Arduino will have some trouble outputting 8mhz. Some things I read mention the chip runs at a 16mhz while another source tells me some code that simply tells a pin to on and then off in the loop as fast as possible will output 2mhz.

_________________
home made noise and electronic ill-logic
Back to top
View user's profile Send private message Visit poster's website
Grumble



Joined: Nov 23, 2015
Posts: 755
Location: Netherlands
Audio files: 23

PostPosted: Thu May 03, 2018 1:48 am    Post subject: Reply with quote  Mark this post and the followings unread

(see my previous post)
I would have the arduino program the AD9833 to output 8MHz, and if I want a frequency of 8.01MHz I would have the arduino to program the AD9833 to output 8.01MHz.
When you buy a breakoutboard with an AD9833 like THIS, you can program the AD9833 to a frequency well over 8MHz

_________________
my synth
Back to top
View user's profile Send private message Visit poster's website
PHOBoS



Joined: Jan 14, 2010
Posts: 4029
Location: Moon Base
Audio files: 588

PostPosted: Thu May 03, 2018 2:30 am    Post subject: Reply with quote  Mark this post and the followings unread

Most of the time the I see the LTC1799 used for this purpose but I've succesfully used the 74HC4046 myself
which gives you a voltage controllled frequency. You do need the 74HC(T) version though as the standard CMOS
version isn't fast enough.

_________________
"My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger
stolenfat



Joined: Apr 17, 2008
Posts: 472
Location: Sunny Oakland California
Audio files: 1

PostPosted: Fri May 11, 2018 1:37 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks for the replies mates - i think given the research i looked into and the knowledge you all provided i think I'll end up mangling something simpler together. Since it's a circuit bent project I dont really wanna buy/order more stuff to make it so. Takes the spirit out of it, no? I'll save my spare arduinos for something else as I think this project will be fun to just explore and see what happens.

I'm pretty determined to just add a switch to go between my best substitute clock circuit, the 40106 with a 1pf cap (the 4046 i tried didnt event get close to matching the rate of the 40106), and the crystal. It may result in the cpu crashing more but that's what circuit bending is all about. Thanks again for all the input.

There are two TC40H00P ic's on this sucker that seems to react interestingly to 0 and v+ voltages. The datasheet claims they are 4011 clones and I'm considering desoldering the chips and replacing them with something else.

@phobos: If my memory serves right, in the past didn't you wizard up a way using a muxer, maybe a 4051, that you could manipulate to act as a nand/nor/xnor or what have you based on some switch statuses? (I gotta do more digging)

_________________
home made noise and electronic ill-logic
Back to top
View user's profile Send private message Visit poster's website
JovianPyx



Joined: Nov 20, 2007
Posts: 1678
Location: West Red Spot, Jupiter
Audio files: 191

PostPosted: Fri May 11, 2018 6:04 am    Post subject: Reply with quote  Mark this post and the followings unread

+1 for a 74HC4046. It is plenty fast enough to do 8 MHz, can be voltage controlled and outputs a proper square wave to be used as a clock.
_________________
FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.
Fruit flies when you're having fun.
BTW, Do these genes make my ass look fat?
corruptio optimi pessima
Back to top
View user's profile Send private message Visit poster's website
PHOBoS



Joined: Jan 14, 2010
Posts: 4029
Location: Moon Base
Audio files: 588

PostPosted: Fri May 11, 2018 12:58 pm    Post subject: Reply with quote  Mark this post and the followings unread

stolenfat wrote:
@phobos: If my memory serves right, in the past didn't you wizard up a way using a muxer, maybe a 4051, that you could manipulate to act as a nand/nor/xnor or what have you based on some switch statuses? (I gotta do more digging)

yep, AXN gate, posted here
Posted Image, might have been reduced in size. Click Image to view fullscreen.

_________________
"My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger
Display posts from previous:   
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 1 of 1 [8 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Circuit Bending
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use