https://learn.sparkfun.com/tutorials/av … e-overview
To set the active cursor position, send the control character 254 followed by 128 + row + position.
To give this a shot, check out the complete example sketch in the GitHub repo or copy and paste the following into your Arduino IDE:
/*
OpenLCD is an LCD with Serial/I2C/SPI interfaces.
By: Nathan Seidle
SparkFun Electronics
Date: April 19th, 2015
License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
OpenLCD gives the user multiple interfaces (serial, I2C, and SPI) to control an LCD. SerLCD was the original
serial LCD from SparkFun that ran on the PIC 16F88 with only a serial interface and limited feature set.
This is an updated serial LCD.
This example shows how to change the position of the cursor. This is very important as this is the
fastest way to update the screen, ie - rather than clearing the display and re-transmitting a handful of bytes
a cursor move allows us to re-paint only what we need to update.
We assume the module is currently at default 9600bps.
We use software serial because if OpenLCD is attached to an Arduino’s hardware serial port during bootloading
it can cause problems for both devices.
Note: If OpenLCD gets into an unknown state or you otherwise can’t communicate with it send 18 (0x12 or ctrl+r)
at 9600 baud while the splash screen is active and the unit will reset to 9600 baud.
Emergency reset: If you get OpenLCD stuck into an unknown baud rate, unknown I2C address, etc, there is a
safety mechanism built-in. Tie the RX pin to ground and power up OpenLCD. You should see the splash screen
then “System reset Power cycle me” and the backlight will begin to blink. Now power down OpenLCD and remove
the RX/GND jumper. OpenLCD is now reset to 9600bps with a I2C address of 0x72. Note: This feature can be
disabled if necessary. See Ignore Emergency Reset for more information.
To get this code to work, attached an OpenLCD to an Arduino Uno using the following pins:
RX (OpenLCD) to Pin 7 (Arduino)
VIN to 5V
GND to GND
Command cheat sheet:
ASCII / DEC / HEX
‘|’ / 124 / 0x7C - Put into setting mode
Ctrl+c / 3 / 0x03 - Change width to 20
Ctrl+d / 4 / 0x04 - Change width to 16
Ctrl+e / 5 / 0x05 - Change lines to 4
Ctrl+f / 6 / 0x06 - Change lines to 2
Ctrl+g / 7 / 0x07 - Change lines to 1
Ctrl+h / 8 / 0x08 - Software reset of the system
Ctrl+i / 9 / 0x09 - Enable/disable splash screen
Ctrl+j / 10 / 0x0A - Save currently displayed text as splash
Ctrl+k / 11 / 0x0B - Change baud to 2400bps
Ctrl+l / 12 / 0x0C - Change baud to 4800bps
Ctrl+m / 13 / 0x0D - Change baud to 9600bps
Ctrl+n / 14 / 0x0E - Change baud to 14400bps
Ctrl+o / 15 / 0x0F - Change baud to 19200bps
Ctrl+p / 16 / 0x10 - Change baud to 38400bps
Ctrl+q / 17 / 0x11 - Change baud to 57600bps
Ctrl+r / 18 / 0x12 - Change baud to 115200bps
Ctrl+s / 19 / 0x13 - Change baud to 230400bps
Ctrl+t / 20 / 0x14 - Change baud to 460800bps
Ctrl+u / 21 / 0x15 - Change baud to 921600bps
Ctrl+v / 22 / 0x16 - Change baud to 1000000bps
Ctrl+w / 23 / 0x17 - Change baud to 1200bps
Ctrl+x / 24 / 0x18 - Change the contrast. Follow Ctrl+x with number 0 to 255. 120 is default.
Ctrl+y / 25 / 0x19 - Change the TWI address. Follow Ctrl+x with number 0 to 255. 114 (0x72) is default.
Ctrl+z / 26 / 0x1A - Enable/disable ignore RX pin on startup (ignore emergency reset)
‘-’ / 45 / 0x2D - Clear display. Move cursor to home position.
/ 128-157 / 0x80-0x9D - Set the primary backlight brightness. 128 = Off, 157 = 100%.
/ 158-187 / 0x9E-0xBB - Set the green backlight brightness. 158 = Off, 187 = 100%.
/ 188-217 / 0xBC-0xD9 - Set the blue backlight brightness. 188 = Off, 217 = 100%.
For example, to change the baud rate to 115200 send 124 followed by 18.
*/
#include <SoftwareSerial.h>
SoftwareSerial OpenLCD(6, 7); //RX (not used), TX
int counter = 250;
void setup()
{
Serial.begin(9600); //Start serial communication at 9600 for debug statements
Serial.println(“OpenLCD Example Code”);
OpenLCD.begin(115200); //Begin communication with OpenLCD
//Send the reset command to the display - this forces the cursor to return to the beginning of the display
OpenLCD.write(‘|’); //Send setting character
OpenLCD.write(‘-’); //Send clear display character
OpenLCD.print("Hello World! Counter: "); //For 16x2 LCDs
//OpenLCD.print("Hello World! Counter: "); //For 20x4 LCDs
}
void loop()
{
OpenLCD.write(254); //Send command character
OpenLCD.write(128 + 64 + 9); //Change the position (128) of the cursor to 2nd row (64), position 9 (9)
OpenLCD.print(counter++); //Re-print the counter
//OpenLCD.print(" "); //When the counter wraps back to 0 it leaves artifacts on the display
delay(2); //Hang out for a bit if we are running at 115200bps
}