Page 1 of 1

why so many pins for 32x16 DMD?

Posted: Sun Oct 21, 2018 5:44 pm
by farrukh
Hi!
I'm new to these displays, I've used max7219 with different displays but that only use SPI pins but this display has many connections, can someone please mention purpose of these pins? and do we need all these pin connected to Arduino even if we use SPI?

digitalWrite(PIN_DMD_A, LOW); //
digitalWrite(PIN_DMD_B, LOW); //
digitalWrite(PIN_DMD_CLK, LOW); //
digitalWrite(PIN_DMD_SCLK, LOW); //
digitalWrite(PIN_DMD_R_DATA, HIGH); //
digitalWrite(PIN_DMD_nOE, LOW); //

Re: why so many pins for 32x16 DMD?

Posted: Sun Oct 21, 2018 10:21 pm
by Brissieboy
The SPI interface requires the 3 lines:
- PIN_DMD_CLK
- PIN_DMD_SCLK
- PIN_DMD_R_DATA
There is plenty of resources available which explain how this interface works.
The DMD is arranged in 4 blocks and the 2 lines:
- PIN_DMD_A
- PIN_DMD_B
are used to select which 1 of the 4 is currently active.
And finally PIN_DMD_nOE is used to blank the display while data is moving around or unstable, then light it up once the data is stable.
And yes, you do need all of them to run these DMDs.
Have a look at this thread for some more info on the DMD which you might find helpful.

Re: why so many pins for 32x16 DMD?

Posted: Mon Oct 22, 2018 9:52 am
by farrukh
Hi!
thanks a lot of such a detailed response, I'm already able to run it successfully, will try with esp8266, will also share code once it works. many people did it but are stingy, only show demo but don't share codes.
thanks.