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In this example we will add an Arduino LCD keypad shield to a ST Nucleo F334R8. This is a 16×2 LCD Keypad module for Arduino Diecimila Duemilanove, UNO, MEGA1280, MEGA2.
It consists of a 1602 white character blue backlight LCD. The keypad consists of 5 keys — select, up, right, down and left. To save the digital IO pins, the keypad interface uses only one ADC channel. The key value is read through a 5 stage voltage divider.
Here are the pins and their functions
Pin | Function |
---|---|
Analog 0 | Button (select, up, right, down and left) |
Digital 4 | DB4 |
Digital 5 | DB5 |
Digital 6 | DB6 |
Digital 7 | DB7 |
Digital 8 | RS (Data or Signal Display Selection) |
Digital 9 | Enable |
Digital 10 | Backlit Control |
Here is a picture of this shield
Code
The code is for the mBed online compiler at https://developer.mbed.org/ and uses the freetronics LCD library
[codesyntax lang=”cpp”]
#include "mbed.h" #include "freetronicsLCDShield.h" freetronicsLCDShield lcd(D8, D9, D4, D5, D6, D7, D1, A0); int main() { lcd.cls(); // print the first line and wait 3 sec lcd.printf("LCD test"); wait(3); // print the counter prefix; the number will be printed in the while loop lcd.setCursorPosition(1, 0); lcd.printf("seconds : "); int i=1; while (i++) { lcd.setCursorPosition(1, 11); lcd.printf("%d", i); wait(1); } }
[/codesyntax]