Libray for character LCD modules (Busy flag/random pins)

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

Hi,

Your program must keep track of the cursor position.

As I said, in my library are only low-level routines
which are called by the Bascom compiler.

Best regards,

Luciano

glena · Joined: 25 Jul 2007 Posts: 284 Location: PA near Philly

Luciano,

Thanks for putting in the time out so that if there is a hardware error with the LCD the program will continue and not lock up.

Once very small addition I would consider is setting a failed flag if the time out is reached. This will (if desired) give the programmer the option of knowing that there is a hardware issue and maybe taking some other action. I consider this a very low priority and would not add it unless there are other changes being made.

-Glen

Ross_ValuSoft · Posted: Sun Sep 11, 2011 6:22 am Post subject:

Adding my thanks also Luciano.

Cheers,

Ross McKenzie
Melbourne Australia

Frankeman · Joined: 11 Aug 2004 Posts: 948 Location: the Netherlands

Hi Luciano,

Are you willing to enhance the LUC_Lcd4busy_timeout library so that the internal ERR flag is set when a timeout occurs.
Just like for example the HexVal and I2Csend statements does.

Best regards, Frank

Frankeman · Joined: 11 Aug 2004 Posts: 948 Location: the Netherlands

In the "Mixing ASM and BASIC" topic in the help file is described how to set the ERR flag.
ASM is not my favorite thing, but i think it can be done in a few lines of ASM.

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

Hi Frank,

Not really useful because the LCD can also crash while its busy flag is low.
You can also have an LCD where the communication works OK but with
no output on the LCD because the display driver is broken.

* * *

(If you still want to implement it).

Recent AVR chips have General Purpose I/O Registers.

(ATmega48/88/168datasheet).

The ATmega48/88/168 contains three General Purpose I/O Registers.
These registers can be used for storing any information, and they
are particularly useful for storing global variables and Status Flags.
General Purpose I/O Registers within the address range 0x00 - 0x1F are
directly bit-accessible using the SBI, CBI, SBIS, and SBIC instructions.

* * *

With these three registers (GPIOR0, GPIOR1 and GPIOR2) you have space for
up to 24 flags.

Below is what you have to do to set and clear one of these flags in my LIB.
(First we set our flag GPIOR0,0 and then we clear it if no timeout occurred).

In your Bascom program, in order to detect the error you will have to
check if the bit is set in the register GPIOR0.
(If GPIOR0.0 = 1 Then...).

You can do the same with the Bascom ERR flag (R6 bit 2) but then you are
not sure if the error was raised by the LCD routine or by a function you have
called as parameter in the Bascom LCD command. (In case this function
also uses ERR). Same problem if the Bascom ERR flag is set by the code in
an interrupt service routine which has interrupted the LCD command.

Best regards,

Luciano

(File LUC_lcd4busy_timeout.lib).

Frankeman · Joined: 11 Aug 2004 Posts: 948 Location: the Netherlands

Hi Luciano,

Thank you very much for your explanation.
It takes only two lines of ASM.

I really like to know when a LCD fails.
The hardware monitors the carbon monoxide value in fluegasses.
Nobody looks at the display until a level is measured that is to high.
In that case it would be nice if the display works (-:
When the display craches under normal conditions it can be replaced.

Frank.

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

Hi Luciano,

I am trying to use your LUC_lcd4busy_timeout.lib but cannot get it to compile without changing LCDMODE to from PIN to BUS. The compiler errors are:

Error40 Line 2346 Variable can not be used with RESET [PORTG], in file
Error41 Line 2346 Variable can not be used with SET [PORTG], in file

I am using an ATMEG32a