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[AVR] Driving Large 2.3" 7 Segment Display serially using MAX7219

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The schematic shown about is what i am trying implement.

Just problem is 74HC540 is not available with me. Is there any other option to drive 2.3" Inch Large seven segment display from MAX7219 ?

I have read datasheet and it says. it can sink 500mA max for total of 8 digits. I have big 2.3" 4 Display consuming around 500mA. I directly tried to sink with MAX7219 No issue it works. But still i find it unsafe to avoid damage to Max7219 driver ic.

Any suggestions ?

I want to drive 4 x 7 Segment 2.3" inch display using SPi. and also i want to change brightness using Max7219 intensity register (0-A).

Please share some thoughts..!:grin:
 

I am not sure how your circuit is planned to work. The ULN2803 will pull each digit to ground with a high input.
If I read the MAX7219 correct, the digits outputs are active high, and since the 2803 uses a active high input the circuit does not need the74HC540. I hope you plan to use resistors in series with each segment.
 

You should emulate led currrent somehow because MAX7219 using current driver for each segment. I recomend you to use MAX7219 directly.
 
Easyrider83 said:
You should emulate led currrent somehow because MAX7219 using current driver for each segment. I recomend you to use MAX7219 directly.
Click to expand...

Wonderful....it worked like charm :) working normal. Just used Positive side driver UDN2981 and Sink side directly to MAX7219. Initially i though it would get hot, but nothing.

Thanks...for your support.
 

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