Controlling 4 7-segment displays

Hi everybody. How can I connect 4 7-segment displays to Arduino. Maybe via other chip. Thanks for any help.

Works perfectly for common-cathode displays as the chip implements a BCD to 7-segment decoder. Up to eight digits (yo code it according to how many). Requires one resistor to control LED current for all, and a couple of bypass capacitors.

It does not however display HEX characters A to F. If you need this, or need to use common-anode displays, you code for the patterns yourself.

Datasheet. Description.

Code? Search on this site.

http://forum.arduino.cc/index.php?topic=233532.0

this is a 3 7-segment display example. figure out by your own on how to make it to become 4~ ^^

MA7219 works with common cathode displays.
In No Decode mode, you can make all these letters:
A,b,C,c,D,d,E,F,g,H,h,I,J,L,O,P,S,U, and
0,1,2,3,4,5,6,7,8,9
Decode mode supports 0,1,2,3,4,5,6,7,9,H,E,L,P directly.

CrossRoads:
MA7219 works with common cathode displays.

Or in No Decode mode, with common anode displays, granted that the code will be more convoluted.

But - it's only code. That's what microcontrollers are good at! You code to get around hardware limitations.

Another suggestion for you, 0xN35T, no extra chips required, just 4 NPN transistors and a few resistors:

http://forum.arduino.cc/index.php?topic=188135.0

Paul

I can't see charlieplexing working when there's 60 digits to control across 15 4-digit displays.

CrossRoads:
I can't see charlieplexing working when there's 60 digits to control across 15 4-digit displays.

Me neither, Bob! But why did you even think of it? Did I miss something?

Here's my vision: 15 shift registers, each sinking current from a 4-digit display, daisychained with SPI.transfer to load them with data.
4 PNP or P-channel MOSFETs, one at a time turned on, to allow one digit from each group to be on.

charlieplexing -thought I saw that mentioned...

If one had 4 discrete displays, charlie plexing looks feasible, not so much for a multi-digit display with all segments in parallel.

CrossRoads:
Here's my vision: 15 shift registers

Huh? For 4 x 7 segment displays? I'm really confused now. The OP must be utterly baffled.

Is there another thread on this same question, but different requirements?

Ignore my posts, there is another thread ongoing for 15 x 4x7segment displays.

0xN35T:
How can I connect 4 7-segment displays to Arduino. Maybe via other chip.

Yes. I use a 20mm common cathode 4x7 with a MAX7221 multiplexer.

Article is here Arduino Playground - MAX72XXHardware

Example is here Usable 4x7 LED with 7221 - LEDs and Multiplexing - Arduino Forum

There may be more elegant code around, but it isn't easy to find.

4 digit common anode displays you can drive with a SAA1064 from NXP (ex Philips).
A lib for this chip can found by google :slight_smile:
This is a nice solution via I2C for a panel display with up to 2m cable 4 wire shilded (is use a pice of LAN-cable)

So for little time I wondered if I can use ATtiny2313 w/ some kind of serial communication like this:
ARDUINO--------ATTINY
DPin1TX -----> DPin0RX
DPin0RX ----> DPin1TX
And if I can connect multiple chips to one serial connection?