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I am using some sensors with the arduino which take a second to receive the data from them. My guess is that there is a delay used somewhere in the library. During this time the multiplexed displays stop working as the rapidly changing grounds are temporarily paused and only one of the displays has the digit lit up. I could change the sensor I'm using (DHT11) to something I could AnalogRead, however I'm curious if there is an external IC for this which drives multiplexed displays with some sort of serial communication or I2C between the arduino and it. I could use a separate arduino(or ATTiny) and write some code for it to do this, but is there a class of chips which already do this? Something where you could pass bytes of the digits and the multiplex delay and it continues to multiplex until the next data is received.

I don't mind if in this time the digits are left in their last states similar to how it would operate if they were directly driven rather than multiplexed. If anyone has insight that would be great!

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Perhaps a MAX7219 would do what you want.

The MAX7219CNG+ is a 8-digit serially interfaced LED Display Driver for LED matrix displays. The MAX7219 is compact, serial input/output common-cathode display drivers that interface microprocessors (¦ÌPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers and an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs. A convenient 4-wire serial interface connects to all common ¦ÌPs. Individual digits may be addressed and updated without rewriting the entire display. The MAX7219 also allow the user to select code-B decoding or no-decode for each digit.

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