LED Matrix: Difference between revisions

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[[Media:LT1441M Datasheet.pdf|Datasheet]]
[[Media:LT1441M Datasheet.pdf|Datasheet]]


[http://www.flickr.com/photos/nottinghack/sets/72157626208320800/ Pictures]
[https://github.com/NottingHack/LED-Matrix-board Git Hub Repo]


[https://github.com/NottingHack/LED-Matrix-board Git Hub Repo]
{{#widget:Flickr gallery|mode=photoset|id=72157626208320800}}


= Talking to the Displays =
= Talking to the Displays =


The displays use shift registers in order to control the led's.
The displays uses shift registers in order to control the LEDs.
There are 256 LED's per panel, that 2048 in total.
There are 256 LEDs per panel, that's 2048 in total.
Data is shifted out over the GSI and RSI pins in time with the CLOCK.
Data is shifted out over the GSI and RSI pins in time with the CLOCK.
After clocking out all 2048 pixels of LATCH the data.
After clocking out all 2048 pixels, LATCH the data.
 
Below is an modifed version of the Arduino shiftOut that out puts data on both GSI and RSI pins for the same clock cycle.


Below is an modifed version of the Arduino shiftOut that out puts data on both GSI and RSI pins for the same clock cycle


<syntaxhighlight lang="cpp">
<blockquote><syntaxhighlight lang="cpp">
void shiftOutDual(int dataPin, int dataPin1, int clockPin, int bitOrder, int val, int val1){
void shiftOutDual(int dataPin, int dataPin1, int clockPin, int bitOrder, int val, int val1){


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}  
}  
</syntaxhighlight>
</syntaxhighlight></blockquote>
 
 
 


== Connectors ==
== Connectors ==
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! Function
! Function
|-
|-
| 1
| 1 || V1 || Power supply for LED (red)
| V1
| Power supply for LED (red)
|-
|-
| 2
| 2 || GND1 || Ground for IC
| GND1
| Ground for IC
|-
|-
| 3
| 3 || VDD || Power supply for IC
| VDD
| Power supply for IC
|-
|-
| 4
| 4 || GND2 || Ground for LED
| GND2
| Ground for LED
|-
|-
| 5
| 5 || V2 || Power supply for LED (yellow-green)
| V2
| Power supply for LED (yellow-green)
|-
|-
|}
|}
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! Function
! Function
|-
|-
| 1
| 1 || GSI || Serial data yellow-green
| GSI
| Serial data yellow-green
|-
|-
| 2
| 2 || /GAEO || Output enable for yellow-green
| /GAEO
| Output enable for yellow-green
|-
|-
| 3
| 3 || LATCH || Latch contents of shift register
| LATCH
| Latch contents of shift register
|-
|-
| 4
| 4 || GND1 || Ground of IC
| GND1
| Ground of IC
|-
|-
| 5
| 5 || CLOCK || Clock Signal for data (read on L->H)
| CLOCK
| Clock Signal for data (read on L->H)
|-
|-
| 6
| 6 || /RAEO || Output enable for red
| /RAEO
| Output enable for red
|-
|-
| 7
| 7 || RSI || Serial data red
| RSI
| Serial data red
|-
|-
|}
|}




[[Category:Projects]]
[[Category:Projects]]
[[Category:Network]]

Latest revision as of 16:00, 31 January 2019

We have 8 LT1441M display modules that have been donated by Michael Erskine. 'RepRap' Matt started working on getting Arduino talking to the displays.

Datasheet

Git Hub Repo

Error in widget Flickr gallery: Unable to load template 'wiki:Flickr gallery'

Talking to the Displays

The displays uses shift registers in order to control the LEDs. There are 256 LEDs per panel, that's 2048 in total. Data is shifted out over the GSI and RSI pins in time with the CLOCK. After clocking out all 2048 pixels, LATCH the data.

Below is an modifed version of the Arduino shiftOut that out puts data on both GSI and RSI pins for the same clock cycle. 


void shiftOutDual(int dataPin, int dataPin1, int clockPin, int bitOrder, int val, int val1){

	int i;

	for (i = 0; i < 8; i++)  {
		if (bitOrder == LSBFIRST) {
			digitalWrite(dataPin, !!(val & (1 << i)));
			digitalWrite(dataPin1, !!(val1 & (1 << i)));
		}else{
			digitalWrite(dataPin, !!(val & (1 << (7 - i))));
			digitalWrite(dataPin1, !!(val1 & (1 << (7 - i))));
                }

		digitalWrite(clockPin, HIGH);
		digitalWrite(clockPin, LOW);

	}

}

Connectors

Power: JST VH connector: http://www.jst.co.uk/productSeries.php?pid=133

Pin No. Name Function
1 V1 Power supply for LED (red)
2 GND1 Ground for IC
3 VDD Power supply for IC
4 GND2 Ground for LED
5 V2 Power supply for LED (yellow-green)

Data: JST XH connector: http://www.jst.co.uk/productSeries.php?pid=136

Pin No. Name Function
1 GSI Serial data yellow-green
2 /GAEO Output enable for yellow-green
3 LATCH Latch contents of shift register
4 GND1 Ground of IC
5 CLOCK Clock Signal for data (read on L->H)
6 /RAEO Output enable for red
7 RSI Serial data red
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