LCD display bug in the latest version 1.6.6

[AlexRH93]

Hola soy Alex Rodríguez, estudiante de robótica y me iniciado en la programación de micro controladores este curso lo que me parece un mundo realmente interesante.
El día 12/11/2015 con la versión del software 1.6.6 experimente un fallo con la pantalla LCD PCF8574T, ya que solo se mostraba un carácter en cada fila de la pantalla , en el ejemplo "Hello world", aparecía la "H" y la "w".
Al principio parecía un error de las librerías LiquidCrystal, pero cuando añadimos las nuevas tampoco funcionaba correctamente.

Al final decidimos probar el ejemplo en otro ordenador con la versión 1.6.5 del software y la misma placa y pantalla y funcionaba perfectamente, asín que estamos casi convencidos que es fallo de la versión 1.6.6.

Hi I'm Alex Rodriguez, a robotics and I started programming in microcotroladores this course which I think is a really interesting world.
Yesterday the software version 1.6.6 develop a fault with PCF8574T LCD screen , it showed only one character in each row of the display , in the example "Hello world" , it appeared showed the "H "and" w " .
At first it seemed an error of LiquidCrystal librarie, but when we add the new didnt work properly.

In the end we decided to try the example on another computer with version 1.6.5 of the software and the same plate and screen and it worked perfectly , asynchronous we are almost convinced that it is version 1.6.6 phallus .

[cmaglie]

Hi @AlexRH93

this bug has been already reported, can you post a (possibly simple and small) sketch that shows the problem?
are you using LiquidCrystal or LiquidCrystal_I2C?
which board are you using?

[cmaglie]

@AlexRH93
I don't know if this may be related your problem:
johnrickman/LiquidCrystal_I2C#5

[serge123]

If you have a problem to use LiquidCrystal_I2C library with LCD - LCD does not display all symbols,
try to edit arduino core library .../hardware/arduino/avr/cores/arduino/Print.cpp, find:

/* default implementation: may be overridden _/
size_t Print::write(const uint8_t *buffer, size_t size)
{
size_t n = 0;
while (size--) {
if (write(_buffer++)) n++;
else break;
}
return n;
}

Change it to:

/* default implementation: may be overridden _/
size_t Print::write(const uint8_t *buffer, size_t size)
{
size_t n = 0;
while (size--) {
n += write(_buffer++);
}
return n;
}

Or use patch with Linux console from .../cores/arduino/
patch -p0 < Print.cpp.patch.txt
Print.cpp.patch.txt

[cmaglie]

@serge123
instead of reverting Print::write it would be better to fix LiquidCrystal_I2C as I've already reported here:

https://github.com/marcoschwartz/LiquidCrystal_I2C/pull/5/files

 LiquidCrystal_I2C.cpp 
@@ -9,7 +9,7 @@
 #define printIIC(args) Wire.write(args)
 inline size_t LiquidCrystal_I2C::write(uint8_t value) {
    send(value, Rs);
-   return 0;
+   return 1;
 }

 #else 

Are you aware of other wrong implementations of LiquidCrystal_I2C (besides the one linked above)?

[serge123]

@cmaglie
No, I don't.
Thank you for LiquidCrystal_I2C.cpp fix. It also works for me.