{"id":7136,"date":"2013-02-20T23:23:24","date_gmt":"2013-02-21T04:23:24","guid":{"rendered":"http:\/\/embedded-lab.com\/blog\/?p=7136"},"modified":"2014-04-01T22:10:59","modified_gmt":"2014-04-02T02:10:59","slug":"new-version-of-max7219-based-4-digit-serial-seven-segment-led-display","status":"publish","type":"post","link":"https:\/\/embedded-lab.com\/blog\/new-version-of-max7219-based-4-digit-serial-seven-segment-led-display\/","title":{"rendered":"New version of MAX7219 based 4-digit serial seven segment LED display"},"content":{"rendered":"

This (SPI7SEGDISP4.40-1R) is a revised version of the previous SPI seven segment LED display<\/a><\/strong> (4 digit) board that displayed numerals and decimal points. The new version has a better quality seven segment LED display (LTC-4727JS<\/strong>)\u00a0with three extra LED segments, as shown below. The additional colon segments are useful in projects where you need to display time (HH:MM or MM:SS).<\/p>\n

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Newer version of 4-digit SPI seven segment LED display<\/p><\/div>\n

<\/p>\n

The digits layout and internal circuit diagram of LTC-4727JS is shown here.<\/strong><\/p>\n

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Digits layout of LTC-4727 JS<\/p><\/div>\n

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Internal circuit diagram<\/p><\/div>\n

The common cathode terminals (Digit 1, Digit 2, Digit 3, and Digit 4) of the four seven segment digits are connected to D3, D2, D1, and D0 pins of MAX7219 driver chip. The common cathode pin 4 of LTC-4727 goes to D4 pin of MAX7219. So, in order to turn on L1, L2, and L3 segments, D4 digit select pin of MAX7219 should be active. Here’s an example that shows how to interface this module with an Arduino board using the LedControl library.<\/p>\n\n

#include "LedControl.h"<\/span>\n\/\/ Arduino Pin 7 to DIN, 6 to Clk, 5 to LOAD, no.of devices is 1<\/span>\nLedControl lc=<\/span>LedControl(<\/span>7<\/span>,<\/span>6<\/span>,<\/span>5<\/span>,<\/span>1<\/span>)<\/span>;<\/span>\nvoid<\/span> setup(<\/span>)<\/span>\n{<\/span>\n \/\/ Initialize the MAX7219 device<\/span>\n  lc.shutdown<\/span>(<\/span>0<\/span>,<\/span>false<\/span>)<\/span>;<\/span>   \/\/ Enable display<\/span>\n  lc.setIntensity<\/span>(<\/span>0<\/span>,<\/span>10<\/span>)<\/span>;<\/span>  \/\/ Set brightness level (0 is min, 15 is max)<\/span>\n  lc.clearDisplay<\/span>(<\/span>0<\/span>)<\/span>;<\/span>     \/\/ Clear display register<\/span>\n}<\/span>\nvoid<\/span> loop(<\/span>)<\/span>\n{<\/span>\n  lc.setDigit<\/span>(<\/span>0<\/span>,<\/span>0<\/span>,<\/span>4<\/span>,<\/span>true<\/span>)<\/span>;<\/span> \/\/ Display 4 to Digit 4, and turn DP on<\/span>\n  lc.setDigit<\/span>(<\/span>0<\/span>,<\/span>1<\/span>,<\/span>3<\/span>,<\/span>true<\/span>)<\/span>;<\/span> \/\/ Display 3 to Digit 3, " "<\/span>\n  lc.setDigit<\/span>(<\/span>0<\/span>,<\/span>2<\/span>,<\/span>2<\/span>,<\/span>true<\/span>)<\/span>;<\/span> \/\/ Display 2 to Digit 2, " "<\/span>\n  lc.setDigit<\/span>(<\/span>0<\/span>,<\/span>3<\/span>,<\/span>1<\/span>,<\/span>true<\/span>)<\/span>;<\/span> \/\/ Display 1 to Digit 1, " "<\/span>\n  lc.setDigit<\/span>(<\/span>0<\/span>,<\/span>4<\/span>,<\/span>7<\/span>,<\/span>true<\/span>)<\/span>;<\/span> \/\/ Turns L1, L2, and L3 on<\/span>\n  delay(<\/span>1000<\/span>)<\/span>;<\/span>\n}<\/span><\/pre><\/td><\/tr><\/table><\/div>\n\n
Note that the DIN, CLK, and LOAD pins of the display are connected to Arduino pins 7, 6, and 5, respectively.\u00a0For more details on MAX7219 device, see the original article<\/a><\/strong>.<\/span><\/p>\n
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Arduino and MAX7219 LED display board<\/p><\/div>\n
You can get an assembled SPI7SEGDISP4.40-1R LED display board for $12.50 on Tindie<\/a><\/strong>.<\/p>\n
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SPI7SEGDISP4.40-1R board is on sale for $12.00 on Tindie<\/p><\/div>\n
Where to buy?<\/strong><\/p>\n
USA buyers<\/strong><\/a><\/p>\n
Other countries buyers\u00a0<\/strong><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
This (SPI7SEGDISP4.40-1R) is a revised version of the previous SPI seven segment LED display (4 digit) board that displayed numerals and decimal points. The new version has a better quality seven segment LED display (LTC-4727JS)\u00a0with three extra LED segments, as shown below. The additional colon segments are useful in projects where you need to display time (HH:MM or MM:SS).<\/p>\n","protected":false},"author":1,"featured_media":7137,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[245,437],"tags":[439,468,438],"class_list":["post-7136","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-embedded-lab-projects","category-products","tag-max7219","tag-serial-seven-segment","tag-spi-led-display"],"_links":{"self":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/7136","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/comments?post=7136"}],"version-history":[{"count":12,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/7136\/revisions"}],"predecessor-version":[{"id":8405,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/posts\/7136\/revisions\/8405"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/media\/7137"}],"wp:attachment":[{"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/media?parent=7136"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/categories?post=7136"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/embedded-lab.com\/blog\/wp-json\/wp\/v2\/tags?post=7136"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}