Questions tagged [max7219]

The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs

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MAX7219 Entering Test Mode and Displaying Random Characters

I'm using MAX7219 with 6 common cathode 38mm (each segment has 2 red LEDs except DP) 7-segments controlled by Arduino Mega2560. I have connected MAX7219 and the board as stated in MAX7219's datasheet (...
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Max7219 and Common Anode Displays, choosing the correct transistors

I've got some common anode 7 Segment displays that I want to use a Maxim 7219 IC to drive with. The Max7219 is designed for direct driving common cathode displays but Maxim do have an app note that ...
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How to use MAX7219 with high current LEDs

I am fairly new to electronics. I am using the MAX7219 to control an led matrix and the data sheet for the MAX7219 says that the maximum current each light can get is 40mA, but for my purpose I need ...
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MAX7219 led matrix prints unwanted artifacts when it is powered up

I’ve got Led matrix 32x8 which is driven by MAX7219. Like this: MAX7219 Dot Matrix Module Microcontroller 4 In One Display with 5P Line When I power it up, I can see different glitches. How to power ...
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LED Matrix creation using resistors & MAX7219

I've been attempting to create my own LED matrix, but now I've plugged it all together I'm getting some unexpected LED's lighting up, it seems some are getting power when they shouldn't (not very ...
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107 views

How to interpret MAX7219 timing diagram?

I'm trying to connect this module to atmega32u4 (16 MHz): Everything seems mostly working, but I have a question: how much time is needed for the latch to take effect? I.e., is a delay needed between ...
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MAX7219, SPI capable/Timing question?

So I purchased a cheap Double-7-Segment display piece (specifically this one: https://www.amazon.com/dp/B01D0WSCJA) To do some tinkering with. I've messed around with it manually to make sure it ...
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177 views

7-Segment Drivers: How do they work/how to handle them?

So I know to drive a 7-segment display you need a TON of pins. However there are 7-segment display drivers (such as the MAX7219) that seem pretty popular. However I'm looking at the datasheet, and am ...
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208 views

MAX7221 not always powering on

I have a MAX7221 SPI 7-seg. LED driver linked to an AVR168P microcontroller. Sometimes when powering on, everything works as expected. Other times the display blanks and remains blank. Other times ...