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electronic:boards:shield:xc4454 [2026/10/15 22:17] – created tonyelectronic:boards:shield:xc4454 [2026/10/16 09:35] (current) – tony
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 ^Manufacturer|made in China| ^Manufacturer|made in China|
 ^Brand|Duinotech| ^Brand|Duinotech|
-^Clone of||+^Clone of|{{https://dfimg.dfrobot.com/enshop/image/data/PDF/Manual/DFR0009_Manual__10_cn.pdf|DFRobot LCD Keypad Shield (2009)}}| 
 +^Other designations|DFR0009|
 ^Arduino compatibility|Uno| /* Uno, Uno R3, Mega, Mega2560 etc */ ^Arduino compatibility|Uno| /* Uno, Uno R3, Mega, Mega2560 etc */
 ^Type|LCD with keypad| ^Type|LCD with keypad|
 ^Voltage|5V| ^Voltage|5V|
-^Current||+^Current| |
 ^Software|| ^Software||
  
-===== Overview =====+^Arduino pin usage|| 
 +^Pin^Shield function^ 
 +^A0|Buttons| 
 +^D4|DB4| 
 +^D5|DB5| 
 +^D6|DB6| 
 +^D7|DB7| 
 +^D8|RS| 
 +^D9|E| 
 +^D10|Backlight|
  
 +===== Overview =====
 +{{electronic:boards:shield:xc4454.png?800|Overview}}
 ===== Features ===== ===== Features =====
-  *+  * 16 Columns x 2 rows of text display 
 +  * Blue backlight 
 +  * 6 Push button keypad (labelled select, up, down, left, right and reset) 
 +  * Contrast control 
 +  * Display uses standard 4bit LCD library 
 + 
 +===== Design Flaws ===== 
 +Andy Gock mentions on his library page  a flaw in the design of the backlight control : "when pin 10 is set to output, and set high, it could cause the IO pin of the MCU (the main Atmel chip) to deliver too much current (over the datasheet’s maximum rating)".  To avoid this: 
 + 
 +    To turn the backlight on, set pin 10 as input. 
 +    To turn the backlight off, set pin 10 as output, and immediately set output low (never high!) 
 + 
 +From the published schematic I can see that the Arduino D10 drives the base of a transitor directly (with no current  limit resistor), this may be the problem he describes. 
 + 
 +  * [[https://forum.arduino.cc/t/warning-to-users-of-some-vendors-lcd-keypad-shields/94673/2|Fault description]] 
 +  * [[https://web.archive.org/web/20121101083518/http://arduino.cc/forum/index.php/topic,96747.0.html|Follow up discussion]] 
 +  * [[https://www.stubmandrel.co.uk/16-electronics/236-dfrobot-lcd-keypad-shield-backlight-fix|Suggested fix using a resistor, and light level control code.]] 
 +  * [[https://www.instructables.com/Arduino-LCD-Backlight-Fix|Suggested fix using a diode.]]
  
 \\ \\
 ---- ----
 ===== Schematics ===== ===== Schematics =====
 +{{electronic:boards:shield:xc4454_sch_red.png?800:XX4454 schematic}}
 \\ \\
 ---- ----
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 ====== References and Additional Resources ====== ====== References and Additional Resources ======
 +  * {{https://dfimg.dfrobot.com/enshop/image/data/PDF/Manual/DFR0009_Manual__10_cn.pdf|DFRobot LCD Keypad Shield (2009)}}
 +  * {{https://web.archive.org/web/20110925063452/http://www.dfrobot.com/wiki/index.php?title=Arduino_LCD%26KeyPad_Shield_(SKU:_DFR0009)|DFRobot LCD Keypad Shield Wiki}}
 +  * {{https://gock.net/blog/2013/arduino-library-for-df-robot-16x2-lcd-keypad-shield|Arduino Library for DF Robot 16×2 LCD Keypad Shield (Andy Gock)}}
  
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electronic/boards/shield/xc4454.1792102676.txt.gz · Last modified: 2026/10/15 22:17 by tony
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