I am attempting to use an arduino uno to control a5 digit display (D2-5L found here).
Here is the schematic of the display:
I tried following various guides for controlling similar displays, but I was unable to make any progress. Am I wrong in thinking it should be as simple as wiring up the strobe, data, and clock to the arduino while using an external power source? If so, help with the code would be greatly appreciated!
Thank you for your time!
Kinda looks like each digit is addressed individually and comms using MISO/MOSI. Where do the strobes connect?
it will not work with arduino except it powers from 5v.
then its working like 74hc595. strobe is latch.
Plus 5V (for the logic) and GND, of course. Study the MIC5821 data sheet for the communication details.
Clock, strobe and data should each be driven via a high side switches (2 transistors each) or a level shifter. You don't want 11 or 12 volts appearing on an Arduino pin.
If you don't need such a bright display effect and use multiplexing, you may need only one instead of five MIC5821 chips.
Not according to the MIC5821 data sheet. It uses 5V logic, when powered by 5V on the logic side.
According to the link in post #1, logic power is 5V.
Power: + 5 VDC, (optional +12 VDC for IO)
There is no obvious reason to follow the posted schematic, showing the logic side to be powered by 11V (for some reason). If that IS the actual schematic of the display, it would be easy to cut PCB traces to separate the power connections. Or perhaps there is an I/O voltage select jumper.
Note also that a transistor inverter is shown on the clock input.
But that 11V clock driver circuit is bizarre!
Yeah their schematic had me confused as far as the 11v goes. I did get ithe schematic directly from the company that makes the board.
Here is a picture of the board itself:
I'm a software guy so I will admit a lot of this is foreign to me. I have some code, but I clearly need to do some additional research into how communicating with the MIC5821s works. Appreciate everyone's time!
Why not ask the company to explain the confusion about whether the logic is 5V or 12V, and why 12V is listed as "optional" on the product web page?
Did you buy the display board with the 12V I/O option already implemented? Or is this salvaged from a piece of equipment?
Hi,
this IC, confirm the datasheet, works with 5V, and with this voltage it can work with frequencies up to 5MHz.
"These devices have greatly improved data-input rates. With
a 5V logic supply they will typically operate faster than 5
MHz."
From the schematic you posted, on the board the +11V comes through a diode, (D1), connected to the +12V.
If you can modify this board, then remove this diode, and in the place where its cathode is connected, you connect a wire, and feed this wire with +5V, you can then use the Arduino directly on the Data and Strobe pins.
I didn't analyze the datasheet of the 2N4401 transistor, but I believe that the clock pin will also work containing it.
As this transistor inverts the clock signal, in Arduino it will have to be generated inverted to meet the IC timing chart.
Hi, @timeoh
Welcome to the forum.
Thank you for supplying a the schematic.
Is the 12V/11V gnd connected to the Arduino gnd.
Your diagram shows two types of gnd and no interconnection.
You will need this connection allow the 5821 to receive the data from the Arduino.
Check your PCB with a DMM and see if 11V is a misprint on the schematic.
Can you please post pictures of your PCB, both sides?
Thanks.. Tom... 
The high voltage is prolly because there are multiple leds in a string in each segment bar.
That display is simply one module usable in a range of systems for ticket issuing and redemption machines. Yes, 12 volt logic is strange but that is what they have used.
Is your objective to interface this circuit board completely unmodified to a Arduino or are you prepared to hack/redesign the board for simplicity of integration with an Arduino.
Thanks @TomGeorge!
Yes the 12v ground is connected to the arduino ground.
Here is the back of the PCB ( I posted the front in a previous comment):
@6v6gt Honestly I'm open to doing it either way. From what people are saying it sounds like using it unmodified with the arduino would be difficult.
I picked this up on ebay for a good price since I needed a scoreboard for the skeeball machine I am working on for my dad. I believe it came from a deltronics ticket eater machine.
One reverse engineering tip: Get a red, black and 3rd color sharpie. Color the ground and Vcc traces black and red and the 3rd color for +12. This will let you easily visualize the power distribution and really help when flipping the card.
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