We have an arduino wich should switch off the 3 communication pins whenever i want to.
We have an Arduino which should switch off the 3 communication pins whenever i want to. So another device can talk to the matrix. The easiest way i know how it will work is a relay. But i need an electronic switch to do the job.
Thank you for the very fast response. Im not realy good in english, but i try my best Ok, lets just remove the second arduino here.We have an arduino wich should switch off the 3 communication pins whenever i want to. So another device can talk to the matrix. The easiest way i know how it will work is a relay. But i need an eletronic switch to do the job.I want to use the LedControl.h library for the matrix. I coudnt find a comand in the library that fits my need, so i want to do it on the hardware side.Phil
Just make those pins INPUT pins, and they are effectively OFF.
Add a 74HC125 to each Arduino. Have one Arduino control the output enables of each chip - only turn on one chip at a time.
So what is this other device and what is the purpose of the whole arrangement?As has been pointed out, it is perfectly easy to set the Arduino pins as INPUT, but if the other device cannot do this you simply use a 74HC4066 as a "relay". There is some concern regarding how these devices will be powered on and off.
Would probably be better, especially in the case of two arduino's, to just have one arduino control the display, and the second communicate with it when something needs to be displayed.
But why? This isn't how displays are driven. The display is driven by some controller, and whatever wantsto talk to the display talks to the controller, not to the display - its a black box effectively.