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Driving an I2C LED Matrix using Arduino IDE for ESP

PostPosted: Mon Jun 01, 2015 2:18 am
by hwiguna


I had to modify Wire initialization in the AdaFruit library but as you can see I was able to use AdaFruit's awesome graphics library on the ESP8266.

UPDATE 6/3/2015:
In ESP8266's Wire library, I discovered a way to set which GPIO pins should be used for I2C. It spat out a warning about deprecated call, but it works and I no longer had to modify any libraries. Schema and code is available on my Hackaday.io page: https://hackaday.io/post/18891

Re: Driving an I2C LED Matrix using Arduino IDE for ESP

PostPosted: Mon Jun 01, 2015 5:47 am
by danbicks
Hi,

Well done this is really nice work. Have you an example sketch for us to have a look at. What mod's was required for the display to work?

Only issue with these displays is simply cost. The Max7219 is a good alternative solution but uses more I/O. ( 1 extra wire than I2c)

Cheers

Dans

Re: Driving an I2C LED Matrix using Arduino IDE for ESP

PostPosted: Mon Jun 01, 2015 9:47 am
by hwiguna
Thanks Dan.
I'm not ready to share code yet. Let me explain...

My original goal was to get an SPI display to work with the ESP.
AdaFruit's library is optimized for ATMega, it uses port manipulations that I'm sure is incompatible with the ESP.
I start to modify it to use slower (but hopefully compatible digitalWrite). However, I have not gotten that to work yet :-(
So, I decided to step back and try I2C first. Success!

So, at this point I'm not certain how much of what I've modified applies to getting I2C to work.
I will certainly share when I got it sorted out. :-)

Re: Driving an I2C LED Matrix using Arduino IDE for ESP

PostPosted: Mon Jun 01, 2015 12:12 pm
by danbicks
No problems mate.

Nice work with the use of the A>D you seem to have this reliable, is that because there is no WIFI going on yet?

I2C works good in this platform. I have an OLED working sweet and will look to incorporate other I2C devices. Would be nice to add WIFI functionality to your project and display messages or icons based on TCP/IP message :)

Keep up the good work.

Dans