Arduino Forum
>
Development
>
Other Hardware Development
>
Drive a shift register with one pin...
Print
Go Down
Pages:
[1]
Topic: Drive a shift register with one pin...
(Read 1 time)
previous topic
-
next topic
westfw
Shannon Member
Posts: 13,447
Karma: 1372
[add]
Strongly opinionated, but not official!
Drive a shift register with one pin...
Jun 13, 2011, 02:17 am
Someone should implement this on an Arduino. You probably need to add a cap to slow the process down to digitalWrite() speeds, but it should still work pretty well!
http://www.edn.com/article/518373-Drive_16_LEDs_with_one_I_O_line.php
CrossRoads
Global Moderator
Unlimited Eagle board sizes available.
Brattain Member
Posts: 45,721
Karma: 2061
[add]
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
http://www.crossroadsfencing.com/BobuinoRev17/
Re: Drive a shift register with one pin...
#1
Jun 13, 2011, 07:48 pm
Interesing oncept. Could be handy in situations needing just a little external hardware.
Not so handy where there might be several shift registers sharing a common data line & clock, with unique output load lines, where parallel output update is needed.
I wonder - is shiftout interruptible? If so, that might lead to some glitches in the output.
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.
Grumpy_Mike
Brattain Member
Posts: 62,920
Karma: 2522
[add]
Solder is electric glue
http://www.thebox.myzen.co.uk
Re: Drive a shift register with one pin...
#2
Jun 13, 2011, 07:55 pm
What a hairy concept. I can't see that being to reliable over the long term or very reliable as it relies on the input capacitance of pins. This will change with different chip manufacturers.
CrossRoads
Global Moderator
Unlimited Eagle board sizes available.
Brattain Member
Posts: 45,721
Karma: 2061
[add]
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
http://www.crossroadsfencing.com/BobuinoRev17/
Re: Drive a shift register with one pin...
#3
Jun 13, 2011, 08:46 pm
I read it as onewould install an external resistor/cap to work with the timing of the source part.
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.
CrossRoads
Global Moderator
Unlimited Eagle board sizes available.
Brattain Member
Posts: 45,721
Karma: 2061
[add]
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
http://www.crossroadsfencing.com/BobuinoRev17/
Re: Drive a shift register with one pin...
#4
Jun 13, 2011, 08:50 pm
Hmm, I guess it does show the internal capacitance.
I still think I'd exgternal, determined empirically to work with the shfitout, or more practically the SPI which should have fixed hardwre, timing and the particular logic family being used.
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.
Print
Go Up
Pages:
[1]
Loading...