why so many pins for 32x16 DMD?

The Dot Matrix Display (DMD) is a 32x16 array of high-brightness LEDs for visually striking effects. [Product Page]
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farrukh
Posts: 2
Joined: Sun Oct 21, 2018 5:35 pm

why so many pins for 32x16 DMD?

Post by farrukh » Sun Oct 21, 2018 5:44 pm

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); //

Brissieboy
Posts: 135
Joined: Fri Sep 20, 2013 7:25 am

Re: why so many pins for 32x16 DMD?

Post by Brissieboy » Sun Oct 21, 2018 10:21 pm

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.

farrukh
Posts: 2
Joined: Sun Oct 21, 2018 5:35 pm

Re: why so many pins for 32x16 DMD?

Post by farrukh » Mon Oct 22, 2018 9:52 am

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.

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