HD44780, i2c

I test the standard "HD44780" library…  
https://github.com/duinoWitchery/hd44780
…and run in an unusual situation.

On an recommendation from the arduino-forum, I start a diagnostic-sketch "i2cexpDiag", which is a part of the library examples. I get this result. Please note the last lines.

Code:

i2c device found at address 0x27
Total I2C devices found: 1
--------------------------------------------------------------------
Scanning i2c bus for all lcd displays (4 max)
 LCD at address: 0x27 | config: P01245673L | R/W control: Yes
Total LCD devices found: 1
--------------------------------------------------------------------
LCD Display Memory Test
Display: 0
 LCD stuck BUSY status
--------------------------------------------------------------------
No working LCD devices


I follow the tip of the author and modify 1 line in the diag-sketch to get more infos and the lcd works!

result:

Code:

********************************************************************
Serial Initialized
--------------------------------------------------------------------
I2CexpDiag - i2c LCD i/o expander backpack diagnostic tool
--------------------------------------------------------------------
hd44780 lib version: 1.3.2
--------------------------------------------------------------------
Reported Arduino Revision: 1.8.19
CPU ARCH: AVR - F_CPU: 16000000
--------------------------------------------------------------------
SDA digital pin: 18 A4
SCL digital pin: 19 A5
--------------------------------------------------------------------
Checking for required external I2C pull-up on SDA - YES
Checking for required external I2C pull-up on SCL - YES

Checking for I2C pins shorted together - Not Shorted
--------------------------------------------------------------------
Scanning i2c bus for devices..

 i2c device found at address 0x27
Total I2C devices found: 1
--------------------------------------------------------------------
Scanning i2c bus for all lcd displays (4 max)
 LCD at address: 0x27 | config: P01245673L | R/W control: Yes
Total LCD devices found: 1
--------------------------------------------------------------------
LCD Display Memory Test
Display: 0
 LCD stuck BUSY status
--------------------------------------------------------------------
Each working display should have its backlight on

and be displaying its #, address, and config information
If all pixels are on, or no pixels are showing, but backlight is on, try adjusting contrast pot
If backlight is off, wait for next test
--------------------------------------------------------------------
Blinking backlight test: to verify BL level autodetection
If backlight is mostly off but
you briefly see "BL Off" on display with backlight on,
then the library autodetected incorrect BL level
and the library cannot autoconfigure the device
--------------------------------------------------------------------
Displaying 'uptime' on all displays
--------------------------------------------------------------------


Now the forum-users ask me to send photos:

Code:

That often indicates a problem with wiring or soldering of the backpack to the LCD or, less likely, the soldering on the backpack itself.

Code:

Can you post some photos of your hardware so we can look at the soldering on the header pins and the PCF89574 chip?

Please forgive me my sarcasm, but where in SimulIDE can I find photos from LCD+PCF8574-soldering…??? …deep hidden on the launchpad-server? ;-)

But seriously:
The lcd works – as you can see in the attachment!
Could it be that "a little" modification solve the problem and everybody can use the components unproblematically?

(tested on SR0 / Linux64)

Please forgive me my sarcasm, but where in SimulIDE can I find photos from LCD+PCF8574-soldering…??? …deep hidden on the launchpad-server? ;-)

Yes, right in the source code you will see that reading from the HD44780 is not implemented.

@arcachofo: do you see a solution about this?

But seriously:
The lcd works – as you can see in the attachment!
Could it be that "a little" modification solve the problem and everybody can use the components unproblematically?

@arcachofo: do you see a solution about this?

The only solution I can see right now is not reading the busy flag.

Could it be that "a little" modification solve the problem

There is no "little modification" that solves this.