Ulli
May 14, 2014, 7:41pm
1
Hi, maybe I was wrong posting it in the LCD forum part
Ulli:@all ,
// select the pins used on the LCD panel
LiquidCrystal lcd(3, 2, 4, 5, 6, 7);
is a kind of standard (I use that pins and it also works in reality).
Now I tried in the declaration part to do it like this:
uint8_t lcd1 = 3;
It also works, even when the lcd1..6 aren't constants...
So I intended to store these 6 values in EEPROM and get their values from there later on. I just wanted more flexibility because I have different hardware using different Arduinos (Uno, Nano) in different configs.
But it doesn't work if I initialize the values later (or just modify the predefined ones). Using `LiquidCrystal(...)` in the `setup()` function doesn't work either, because then it's unknown in `loop()`.
Is there any possibility to use such a flexible configuration?
Using LiquidCrystal(...) in the setup() function doesn't work either, because then it's unknown in loop().
It would be unusual to do it, but can you create the LCD instance in loop() ?
Ulli
May 14, 2014, 9:35pm
3
Now I tried
uint8_t lcd1 = 2; // wrong value for testing overwrite
uint8_t lcd2 = 3; // wrong value for testing overwrite
uint8_t lcd3 = 4;
uint8_t lcd4 = 5;
uint8_t lcd5 = 6;
uint8_t lcd6 = 7;
boolean runOnce = true;
void loop()
{
LiquidCrystal lcd(lcd1, lcd2, lcd3, lcd4, lcd5, lcd6);
if (runOnce){
lcd1 = 3; // load the right value
lcd2 = 2; // load the right value
lcd.begin(16, disp_zeilen); // start the library
lcd.createChar(1, la); // upload 3 user chchars
lcd.createChar(2, ra);
lcd.createChar(3, bell);
runOnce = false;
}
...
It seems to work, but the LCD flickers. :~
LiquidCrystal lcd(lcd1, lcd2, lcd3, lcd4, lcd5, lcd6);Do this just once, not every time through loop().
Ulli
May 14, 2014, 9:43pm
5
But how? In pascal I would look if lcd^ equals nil. How do I the same in C++?
Set a boolean variable, let's call it lcdDone, to false. Test lcdDone before creating the instance. Create the instance if lcdDone is false and set lcdDone to true. Next time through loop() lcdDone will be true and a new instance will not be created.
Ulli
May 14, 2014, 10:03pm
7
If I do it so
uint8_t lcd1 = 2;
uint8_t lcd2 = 3;
uint8_t lcd3 = 4;
uint8_t lcd4 = 5;
uint8_t lcd5 = 6;
uint8_t lcd6 = 7;
boolean runOnce = true;
void loop()
{
// LiquidCrystal lcd(lcd1, lcd2, lcd3, lcd4, lcd5, lcd6);
if (runOnce){
LiquidCrystal lcd(lcd1, lcd2, lcd3, lcd4, lcd5, lcd6);
lcd1 = 3;
lcd2 = 2;
lcd.begin(16, disp_zeilen); // start the library
lcd.createChar(1, la);
lcd.createChar(2, ra);
lcd.createChar(3, bell);
runOnce = false;
}
...
lcd.setCursor(0,0);
I get "lcd" was not declared in this scope when the compiler comes to the lcd.setCursor()
That looks like a dead end then.
Ulli
May 15, 2014, 5:17pm
9
Ulli:
My question meant if I could find out if lcd is not yet defined. If it wouldn't I could do the initialization only once.
Ulli
May 16, 2014, 6:01am
10
Finally, I found a way to do it by myself. So I proudly present it to all of you, folks
#include <LiquidCrystal.h>
void setup(){}
uint8_t l1, l2, l3, l4, l5, l6 = 0;
boolean runOnce, printOnce = true;
LiquidCrystal lcd(l1, l2, l3, l4, l5, l6);
void loop(){
if (runOnce){
l1=8; l2=9; l3=4, l4=5; l5=6;l6=7;
LiquidCrystal lcd1(l1, l2, l3, l4, l5, l6);
lcd = lcd1;
lcd.begin(16,2);
runOnce=false;
}
if (printOnce){
lcd.print("hello world");
printOnce=false;
}
}
Ulli
May 16, 2014, 9:12am
11
So here is the whole thing with the LCD pins stored in the EEPROM 8)
#include <EEPROMex.h>
#include <LiquidCrystal.h>
const int memBase = 0;
uint16_t EEVer = memBase; // Version in 16 bit
uint16_t EELcdRS = memBase + 2; // --> LCD pin RS
uint16_t EELcdEN = EELcdRS + 1; // --> LCD pin EN
uint16_t EELcdD4 = EELcdEN + 1; // --> LCD pin D4
uint16_t EELcdD5 = EELcdD4 + 1; // --> LCD pin D5
uint16_t EELcdD6 = EELcdD5 + 1; // --> LCD pin D6
uint16_t EELcdD7 = EELcdD6 + 1; // --> LCD pin D7
uint8_t LcdRS, // LCD pin RS
LcdEN, // LCD pin EN
LcdD4, // LCD pin D4
LcdD5, // LCD pin D5
LcdD6, // LCD pin D6
LcdD7; // LCD pin D7
LiquidCrystal lcd(0,0,0,0,0,0);
void setup(){
LcdRS = EEPROM.readByte(EELcdRS); // LCD pin RS
LcdEN = EEPROM.readByte(EELcdEN); // LCD pin EN
LcdD4 = EEPROM.readByte(EELcdD4); // LCD pin D4
LcdD5 = EEPROM.readByte(EELcdD5); // LCD pin D5
LcdD6 = EEPROM.readByte(EELcdD6); // LCD pin D6
LcdD7 = EEPROM.readByte(EELcdD7); // LCD pin D7
LiquidCrystal lcd1(LcdRS, LcdEN, LcdD4, LcdD5, LcdD6, LcdD7);
lcd = lcd1; // <-- this is the matchwinner!
lcd.begin(16,2);
lcd.print("hello world");
}
void loop(){}
