Low Prices on 7 Segment Displays Free Shipping Available. Buy Segment 7 on eBay. Money Back Guarantee ... The on-chip includes a BCD decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM to store... The DIN, LOAD and CLOCK pins of.
The MAX7219 is an integrated serial input output common-cathode display driver which is connected to microprocessor or microcontroller along with the 8 bit 7 segment digital LED display. This module you also place the LED Graph display LED or 64 separated LED The SPI7SEGDISP8.56 display module is based on MAXIM's MAX7219 display driver chip that provides a 3-wire serial (SPI) interface to drive 7-segment LED displays (common-cathode type) up to 8 digits. Included on-chip are a BCD decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM to store the digit values . So we have 5V connected to V+ and connected to ground through a 100nF ceramic capacitor and a 10μF electrolytic capacitor. To set the current output from the output pins, which will feed our output device, we connect a 40KΩ resistor to V+ MAX7219 and 8 x 7 Segment LED Display . The code for this can be downloaded from my GitHub page here. This display can be found on eBay here. It consists of two 4 digit seven segment LEDS with a MAX7219 driver IC. I have used the LedControl library available from here, the examples show the basic library use, but I wanted to be able to send data over a Serial connection. The MAX7219 presents.
A look at the MAX7219 8-Digit LED Display 7 Segment Digital Tube For Arduino Raspberry Pi M The 7 segment plugin supports two different chip types, the TM1637 (4 digits) and the MAX7219/21 (8 digits). Hardware ESP TM1637 GPIO <--> CLK GPIO <--> DIO ESP MAX7219 GPIO <--> DIN GPIO <--> CLK GPIO <--> CS Power chip 3.3V* <--> VCC GND <--> GND *Many 7 segment displays state that they need 5V to operate but we have successfully powered them using 3.3V. 8 digit display. Displaying date. I've got a project I'm working on where I need to drive a ton of 7 Segment displays, so instead of dealing with all of the multiplexing myself, like I normal.. 8-Digit Seven Segment Display with MAX7219. Available Languages . Introduction . In this tutorial we will show you how to use the 8-Digit seven segment display with MAX-7219 IC. with the Arduino uno board. Let's get started! What you will need - Hardware For this tutorial you will need: Arduino uno; 8-Digit Seven Segment Display Module The Circuit. The connections are easy, see the image above. Full 7-segment LED display schematic. 3. Software. We use I2C protocol to communicate with RDA5807 Radio module: #include <Wire.h> Define Arduino pins what we use: /* MAX7219 LED driver */ #define MAX7219_DIN 12 #define MAX7219_CS 10 #define MAX7219_CLK 11 /* Rotary Encoder */ #define clkPin 5 #define dtPin 6 #define swPin 2 The code how to use RDA5807 I found it here: https://github.com.
Now to put it to work for us - we'll demonstrate using one or more 8 x 8 LED matrix displays, as well as 8 digits of 7-segment LED numbers. Before continuing, download and install the LedControl Arduino library as it is essential for using the MAX7219. Controlling LED matrix displays with the MAX7219. First of all, let's examine the hardware side of things. Here is the pinout diagram for. Here is another version of Arduino based voltmeter. This time it uses 4-digit 7-Segment LED display and MAX7219 Display Driver.For similar design with 2×16 LCD display click this link.Also you can look at PIC16F876 implementation in my previous post.Interfacing the MAX7219 was covered in this article.You can see in the Arduino sketch attached here that the code is not too complicated and uses. How to control 4 digit 7 segment display with MAX7219. Preparation to build my own custom 4 digit large segments display controlled with Max7219. Intermediate Full instructions provided 5. Things used in this project . Hardware components : Arduino Nano R3: ×: 1: Buy from Newark; Buy from CPC; Maxim Integrated MAX7219/MAX7221 LED Display Drivers: ×: 1: LED (generic) ×: 1: Buy from Newark. The most common form of 7-segment displays are Common Cathode, for which et al. the microchips MAX7219 and MAX7221 are intended. There are also Common Anode, which are usually a lot cheaper. However, these are not directly compatible with such a microchip. How it all works is shown in this tutorial. Anyone who wants to [ 6 digit 7 Segment display - TPIC6B595 schematic component? Arduino Forum > Using Arduino > Project Guidance > 6 digit so good with simple projects (LEDs, speaker, push buttons, small 7 segment display). I'm building a large (2 to 5 inch high numbers) 6 digit 7 segment display. Some background info... I already have my code working while using the embedded-lab SPI7SEGDISP8.56 MAX7219 based.
Step 1: Schematic. The MAX7219 display driver chip provides a 3-wire serial (SPI) interface to drive 7-segment LED displays (common-cathode type) up to 8 digits. The on-chip includes a BCD decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM to store the digit values. The DIN, LOAD and CLOCK pins of MAX7219 is connected with 4,3 and 2 digital IO pins of Arduino. An digital clock made out of 144 7 segment displays Project Owner Contributor 7 Segment display array clock. Frugha. 760 Voice-controlled scrolling message board using an esp32 board, Max7219 display, Google home/mini, IFTTT and Pushbullet Project Owner Contributor Voice controlled scrolling message board. Rob Latour. 210 The MAX7219 is designed to drive common-cathode LEDs and is perhaps the most popular of the LED drivers for driving 7-segment, bar-graph and LED matrix type displays with uCs. The driver provides flexible individual LED segment control as well as basic functions such as turning the display ON/OFF and adjusting the LED brightness I've build an digital clock made out of 144 7 segment displays controlled by an arduino nano. The segments are controlled by 18 MAX7219 ic's which can control up to 64 individual leds or 8 7 segment displays. The array has 144 displays made each up of 8 individual leds so the array has an total off 1152 leds you can control
The MAX7219/MAX7221 are compact, serial input/out-put common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED dis-plays of up to 8 digits, bar-graph displays, or 64 indi-vidual 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. The MAX7219/MAX7221 are compact, serial input/out-put common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED dis-plays of up to 8 digits, bar-graph displays, or 64 indi-vidual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digi Most 7-segment displays actually have 8 segments, with a dot on the right side of the digit that serves as a decimal point. Each segment is named with a letter A to G, and DP for the decimal point: Each segment on the display can be controlled individually, just like a regular LED. There are two types of 7-segment displays - common cathode and common anode. Common Cathode Displays. In common. Hi all. First off, an introduction. I'm John Huebbe... new to electronics but experienced with programming. Just picked up an Arduino and some components a week ago. So far, so good with simple projects (LEDs, speaker, push buttons, small 7 segment display). I'm building a large (2 to 5 inch high numbers) 6 digit 7 segment display
Normally it would allow it to run 8, common cathode, 7-segment displays. The single digit 16-segment display characters I have have 18 pins total. 16 segments, the decimal, and the common cathode. Would it work to wire the first 8 segments to SEG-A -> SEG-DEC and then the cathode to Dig 0 8 Digit 7 Segment MAX7219 Module is an amalgamation of two pieces of 0.56 4 Display 7 Segment Common Cathode Module which is mounted or arranged horizontally and controlled by MAX7219 driver. The advantages of this module is that it only takes 3 pins of I/O as a communication on arduino, so as to minimize the use of arduino I/O pins. This module can be applied to various projects that require. The MAX7219 is a compact, serial input/output common-cathode display drivers that interface Arduino UNO to 7-segment numeric LED displays of up to 8 digits. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM that stores each digit. Only one external resistor R1 provided to set the segment current for all LEDs. A convenient 3. Raspberry Pi and Max7219 7 segment display. by shedboy71 23rd May 2015. In a previous example we connected a Max7219 8×8 LED matrix display to our Raspberry Pi, you can also purchase a 7 segment display which uses the same ic. Here is a typical module. MAX7219 seven segment display. To make life easy there is a python module already available with a couple of examples. Open up a console. Adafruit MAX7219 Library Documentation, Release 1.0 • strg (string) - string to place in to display • bit_value - > 1 sets the text, otherwise resets 6.5 adafruit_max7219.bcddigits.BCDDigits class adafruit_max7219.bcddigits.BCDDigits(spi, cs, nDigits=1) Basic support for display on a 7-Segment BCD display controlled by a Max7219 chip.
A library for using a 7-segment display driven with a MAX7219 or MAX7221 IC. Requires the Arduino framework. - abaskin/MAX72X 7-segment Displays Connection . HCSCI directly supports the most commonly used 7-segment display modules based on the MAX7219, TM1637 and HC595 shift registers, as well as custom displays built on 16-bit LED drivers or shift registers. You can connect as many indicators of different types and sizes as you need to have in your cockpit. It depends on the connection methods you will be using ( an. Index > MobiFlight Hardware & Firmware > Max7219 7 segment display wiring questions. Message #21414. anthonym. Posts: 9. Greetings and Merry Christmas everyone. I am starting work on my next project, the B737 electrical panel, and have come up with another learning opportunity, the MAX7219 IC chip and 7 segment display. My plan is to custom wire 5 separate modules (1x2 digit and 4x3 digit) to. This area is a growing library of the schematics, wiring diagrams and technical photos. Menu. Search for: Posted in Wiring. 7 Segment Display Module Circuit Diagram Posted by Margaret Byrd Posted on September 19, 2020. 4 digit 7 segment led display module introducing a new serial spi 8 print arduino adc values on interfacing with pic seven learn parallax com displays the tm1637. Build Your Own. Part 2: The 2-digit 7-segment display circuit; this post Part 3: Sketch broken down in sections, using a multi-display controller such as the MAXIM MAX7219; sequencing through the displays, which is what we have done in our example, as it requires no added hardware. When we were using a single-digit display, we connected the common anode pin to our Vdd supply, but with two digits we have.
In this circuit, we will show how to display numerals on a 4-digit 7-segment display just by directing using any arduino microcontroller with no other external chips such as LED display drivers. Simply by using transistors to each of the digits of an LED display, we can have sufficient current going to each digit of the LED display to drive them. In this circuit, we're going to connect an. . The MAX7219 LED driver saves you processor pins and processing time! Below, you can find out exactly why this is true and how you can use these devices on an Arduino. You'll also see how to use multiple devices without using any more processor pins! Using a 7219 you can drive 64 LEDs while you only need 3 wires to.
Schematic for MAX7219 with Arduino . NOTE:Due to the fairly high current draw of the display (up to 1A if the brightness is cranked all the way up), it is recommended to drive it directly from a power supply rather than from the microcontroller power or else be sure to keep the brightness turned down to less than 50% to avoid overheating the microcontroller voltage regulator. MAX7219 with. But the idea is to apply this code to other projects with 7 segment displays that I might do later. You can also read more about 7 segment displays in this post. This project is great to learn more about: Reading sensors (in this case temperature) 7 segment displays (4 digit 7 segment displays) 8 bit Shift Registers (74HC595) Pratice wiring. 7 segment display, LED, MAX7219, shift registers. Using 7 Segment LED displays, Part 4 - dual quadruple units By Heikki Hietala 21/04/2020 Leave a comment. Okay, I thought the series on 7 segment LED displays would run into three parts, but it has turned out to be a Douglas Adams-esque trilogy in four parts. I had completely forgotten to write about a clock based on a unit of two 4 digit, 7. max7219. Display. Lightweight library for the MAX7219 7 segment 8 digit display Exposes two easy to use methods DisplayText(Text, Orientation) and DisplayChar(Digit, Char, DecimalPlace)
Most of the 7 segment modules use the MAX7219 led display driver IC. One MAX7219 can control up to 64 individual leds or eight 7 Segment displays. I. OVERVIEW I've used and done tutorials in the past using 7 segment displays modules. These modules are great and easy to use since they have all the parts needed onboard. But sometimes for a project you might need to create your own so that it. In our case, the 7 segment displays both have their own Max7219 chip that drives the LEDs. The chip can address each LED individually. The easiest way to visualize this would be a row of drawers in a cupboard. Each drawer contains a single item. In our case, we have 2 cupboards with 8 drawers each (2, 7 segment modules containing 8 digits each). To change a certain number, we have to select. Week09 - Display 7_Segment and UART Tx B5926329 นายทศพล ข้ามไปยังเนื้อหา. ค้นหาสำหรับ: Thotsaphon Jantree. เมนู. Homepage; My All Blogs. FPGA Project - Read PS2 Keyboard to MAX7219 Display; RPi Project - Cast Youtube from Mobile to RPi; 5.FPGA - Timing Coding; 4. Mojo V3 - Display 7_Segment and UART Tx; 3. Pin Out - 4 Digit 7 Segment Display. A 4-digit 7-segment LED display has 12 pins. 8 of the pins are for the 8 LEDs on each of the 7 segment displays, which includes A-G and DP (decimal point). The other 4 pins represent each of the 4 digits from D1-D4. Common Anode or Common Cathode . Each segment in the display module is multiplexed, meaning it shares the same anode connection points. And. .The reason for this is to research possibility of using this module to build large custom 4 digit seven segment display that can be used to build a clock
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. Included on-chip are a BCD code- Next is the Hookup diagram of the Arduino 4-Digit 7-segment LED Display, followed by the Arduino sketch. Carefully follow the hookup diagram to complete your hardware,and then upload the sketch to Arduino using the Arduino IDE as usual. The finished circuit can display numbers ranging from 0 through 1023, in connection with a 10K preset pot attached to the analog input A0 of the Arduino board arduino_scale. This repository contains the Arduino sketch and the supporting library as well as the schematics for a bathroom scale with auto power-off using a 4-digit 7-segment display and the HX711 and MAX7219 chips.. The code depends on the HX711 library, and on my modification of the LedControl library, which allows an easier way to display characters on the display, though hopefully my. This simple Arduino sketch shows how you can send numbers to the 7-segment display. This time we can let the MAX7219 work out which segments to light up by switching to digits mode. We also set the scan limit to 3 (in other words, 4 segments) which makes each one brighter Multiplexing is done when there are two or more 7 segment displays exist, multiplexing is done by connecting individual segments (A to G) together like illustrated in the above schematic and the common terminals of 7 segment display are treated as select lines, with the help of select lines we can turn ON or OFF the individual 7 segment display
Affordable, Open-Source FPGA. One of the first things that I wanted to do was get my DEADBEEF demo working with SPI on the Max7219 7-Segment display.I've written a post on this in the past for the Mojo using the Lucid HDL, but the TinyFPGA uses Verilog. I had to use the transpiled Verilog source code from the previous project and modify it a little bit to work with the TinyFPGA Display - 7-segment display ¶. Plugin details¶ Type: Display. Name: 7-segment display. Status: NORMAL. GitHub: P073_7DGT.ino. Maintainer: . Used libraries: . Description¶ The 7 segment display plugin allows to display date, time, temperatures, numbers, text and self-created shapes on a 7 segment LED display, using either a TM1637 or MAX7219 driver. Depending on the available space in the. Looking at the Figure 2. MAX7219/MAX7221 Driving 2.3-Inch Displays in the data sheet, it shows you that you need external digit drivers for the common cathode. Figure 3. Cascading MAX7219/MAX7221s to Drive 16 7-Segment LED Digits shows you how the 7219 can drive 0.5 displays without any extra electronics. David
In this example we connect a MAX7219 seven segment display to our ATmega16, the connection was as follows VCC → 5V GND → GND DIN → PB5 CS → PB0 CLK → PB7 Schematic Code [c] sbit Chip 7 Segment And 8x8 Matrix Led Controls Jpralves Net Robot Eye Expressions Using Led Matrix Display Arduino Display Driver Shield With Max7219 Eeweb Community 8x8 Bicolor Matrix And Max7219 Please Help Parallax Forums Arduino Scrolling Text Max7219 24pin Led Matrix Youtube Max7219 Driver For Led Matrix 8 8 The Tinusaur Project 8x8 Led Matrix Max7219 With Arduino Circuit Code Max7219 Led Dot. AZDelivery 5 x MAX7219 Led Modul 8 Bit 7-Segmentanzeige LED Display kompatibel mit Arduino und Raspberry Pi - Kostenloser Versand ab 29€. Jetzt bei Amazon.de bestellen
MAX7219 & PIC MCU = +5V LED DISPLAY = +12V, 500mA POWER ADAPTER I have to interface LED DISPLAY (6 Digits) from PIC MCU thru' MAX7219 IC. MAX7219 for common cathode display. I have used ULN2003 and PNP (BC557) transistors to make it work on MAX7219. I am using bitbanging (not SPI module) method (RA1 - SDO, RA2 - SS, RA3 - SCK). Code works OK. But, if data sent to one digit, it writes on all. You can think of a 7 segment display as 7 individual LEDs in a configuration like the picture below. Image 1 shows the layout and image 2 shows how the segments are arranged . 7 seg Blank. So by lighting certain segments you can display numbers, so for example to display the number 1 you would light segments B and C. Here are more examples. 7 segment. In this example we connect a HDSP-C3Y3.
I'm looking for a solution to drive 3 inch 7-segment common cathode LED displays with a MAX7219 LED driver IC. The displays require 9V 20mA per segment. The 20mA is well within the MAX7219's max segment current of 40mA. However, the MAX only provides 5V to the segments. I've tried this and the only segment that comes on is the decimal point. Dieses 8-stellige 7-Segment-Display-Modul (HCMODU0082) basiert auf dem Maxim MAX7219 LED-Display-Treiber. Das Modul verwendet zwei standardmäßige 4-stellige sieben Segmentanzeigen, um insgesamt 8 Ziffern in Rot mit Dezimalpunkt anzuzeigen. Eine praktische Eingangs- und Ausgangsleiste ermöglicht es, zusätzliche Module mit nur 3 digitalen IO-Pins zu verketten. Zur Montage der Schalttafel hat. Principle: The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers that interface to microcontrollers and microprocessors to control 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on the MAX7219 chip is a BCD code-B decoder, a multiplex scan circuitry, a segment and digit drivers, and an 8×8 static RAM that. MAX7219 7 segment display driver. Datasheet. A simple SPI Matrix / 7 segment display driver, which can be controlled with the MAX7219 (About Modules) module. Wiring. This module needs 5 wires: Power, ground, clock (SPI SCK), data (SPI MOSI), and chip select (can be any pin). Just wire them up, set up SPI, specify the chip select pin, and you're.
Raspberry Pi and Max7219 7 segment display. shedboy71 May 23, 2015 0. In a previous example we connected a Max7219 8×8 LED matrix display to our Raspberry Pi, you can also purchase a 7 segment display which uses the same ic. Here is a typical module. MAX7219 seven segment display. To make life easy there is a python module already available with a couple of examples. Open up a console window. Lightweight library for the MAX7219 7 segment 8 digit display I'm using a PIC18F8722 at 40 MHz to display data on 7-Segment displays. There are 8 digits on each display Each display is driven by a MAX7219 driver. Initially, I had three displays, each on it's own port - all worked OK. Then, to save ports, I daisy-chained the displays (Data_out of one MAX7219 to Data_in of the next). Clock and Data in parallel to all three MAX7219 Initially, all worked Ok. Primär ist der MAX7219 für die Ansteuerung von 7-Segment Displays konzipiert. Er lässt sich aber auch für die Ansteuerung von LED Matrix Displays oder losen LED Arrangements verwenden. Das ist auch nicht weiter verwunderlich, da die Ansteuerung mehrerer 7-Segment Anzeigen im Grunde dieselbe Herausforderung wie die Ansteuerung eines LED Matrix Displays darstellt. Pinout und technische. Equivalent Display Modules. Dot Matrix LED Display, 16×2 LCD Displays, OLED Display, TFT LCD Screen Display 7-segment Display Brief Intro. The seven segments displays are the oldest yet one of the efficient types of display used in embedded applications. This display has nothing more than 8 LED inside it. These 8 LEDs are separated into each segments which can be named as a,b,c,d,e,f,g,DP as.
Mit einem 7 Segment Display können wir eine Zahl von 0 - 9 einfach und gut erkennbar darstellen. In diesem Bauteil ist nicht nur ein 7 Segment Display enthalten sondern insgesamt auf zwei unterschiedlichen Modulen mit jewals vier 7 Segment Displays. Diese müssen auch nicht alle einzelnd angeschlossen werden, diese Aufgabe übernimmt der MAX7219 Chip. Diesen Chip kann einfach über das SPI. LedControl is a library for the MAX7221 and MAX7219 Led display drivers. Only a few components are needed to control 64 Leds or a 7-segment display. There are already lot code-examples for the Arduino and the MAX72XX Led display driver. Most of the projects have their focus on controlling individual Leds layed out in some sort of rectangular matrix. I needed the MAX72XX to drive a few 7. A seven-segment display is commonly used in electronic display device for decimal numbers from 0 to 9 and in some cases, basic characters. Use of light emitting diodes (LEDs) in seven segment displays made it more popular, whereas of late liquid crystal displays (LCD) displays have also come into use. Electronic devices like microwave ovens, calculators, washing machines, radios, digital.
Hello, My 7 Segment display won't work when connected to a MAX7219 Dot Matrix module. I'm getting some lights but nothing changes when turn the knob (heading knob in this example). Can someone tell me if my physical connections are OK or if I'm missing something. The following are my physical connections. Output multiplexer connection. A. In another tutorial, we will show how to control a 8-digit seven-segment display module with LinkIt 7697, by using a dedicated seven-segment display driving IC MAX7219. Mini Servo (EMAX 9g ES08A Servo) Driving 7-segment Displays with MAX7219 Powered by Atlassian Confluence and the Scroll Content Management Add-ons
MAX7219 8-Digit 7-Segment Digital LED Display Overview: This 8-digit red LED numeric display is driven by the MAX7219, using an SPI interface requiring three I/Os. The MAX7219 is an integrated serial input/output common-cathode driver, between the LEDs and the microcontroller. Only one external register is used to set the current of each LED. MAX7219 and 7-segment displays 10 Apr 2012 . Maxim's MAX7219 and MAX72221 chips are really rather handy when it comes to controlling a collection of 7-segment LED displays. They are also quite useful when it comes to controlling up to 64 individual LEDs when appropriately arranged. The main library I found was LEDControl which seems to work for most people, which is great, but it wasn't doing. Wiring the eight-digit 7-segment display breakout board - power considerations. As can be seen in figure 3 the device needs on its VCC pin a 3.3V or 5V power supply, and it needs GND. The current that Arduinos can provide on their 5V pin is limited to 400 mA. Notice that an eight-digit device may have as much as 56 segments and eight dots. One display therefore contains 64 leds. If one.
Examples of such ICs are MAX7219, TM1637 and TM1638. The latter two come with support for keypad, therefore you can build front panels with buttons and display using such ICs. But this post focuses on plain 4 digit 7 segment displays that do not have a driver. They are just a bunch of LEDs wired together in a specific configuration. Since they are very easy to get, many people are interfacing. The MAX7219 is a serial input/output common-cathode display driver that interfaces microprocessors to a 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
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. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM that stores each digit. Only one external resistor is. The MAX7219/MAX7221 are compact serial input/output common-cathode display drivers that provide the interface between microprocessors (µPs) and 7-segment numeric LED displays of up to 8 digits 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 to store each digit. Only one external resistor is required.
100% Brand new and high quality MAX7219 digital display control module This module is compatible with 5V and 3.3V microcontrollers. You you can use it FOR ARDUINO MAX7219 is an integrated serial input / output common-cathode display driver, which connects your microprocessor to a 7-segment digital LED display with 8 digits. Only three IO ports are used to drive the eight digit display. MAX7219. The Maxim MAX7219 is an LED display driver that can control up to 64 individual LEDs, or eight 7-segment LED digits, or any combination of individual LEDs and digits, connected in a matrix of eight rows and eight columns. It frees the host from the chore of constantly multiplexing the 8 rows and 8 columns. In addition, it takes care of brightness control (16 steps), and implements display test. The MAX7219 can only directly drive common cathode displays. Though it should be possible with similar electronics to drive common anode displays. But then you would have the same problem with the inversion, just on the segment drivers instead of the digit drivers. You may be able to find a non-inverting (or rather double inverting) sink driver. I'm not aware of one but I haven't really looked.