Re: [Lcd4linux-devel] Driver & Questions: Futaba VFD M402SD06GL

[Michael R. <mi...@re...>]

Hello Marcus,


> motivated and supported by Robert Resch I wrote a lcd4linux driver to
> run a Futaba VFD M402SD06GL (bought mine in 2005, 40x2 chars) on the
> parallel port. The diff file is attached to this mail.

Fine, thanks! I already committed your driver, so please du a 'svn up' before continueing...


> At the moment the VFD shows no errors, but on the terminal the error
> message...
>
> unable to compact bar characters
> nSegment=3 fSegment=2 CHARS=0 ICONS=0
> Segment[0].val1=0 val2=0
> Segment[1].val1=255 val2=255
> Segment[2].val1=5 val2=1
>
> ... is shown (with variable values). What's to do?

This is because yor display does not support user-defined characters. You have to disable bars and icons in this case.

> Beside this I've some questions/concerns:
>
> 0. I'd like to install a switch on the 5V wire. By connecting the 5V
>     with a status pin (using a 1-10kOhm resistor) I could check in the
>     drivers write function if the VFD is switched off and ignore the
>     commands in this case.
>     But how can I get informed and rewrite all widgets when the VFD
>     is switched on?

lcd4linux does not support this. restarting it (using SIGHUP) is the way to go.

> 1. The driver name might be confusing because current Futaba VFDs seems
>     to run with the HD44780 driver (as LCD emulators).
I see no problem here.

> 2. The VFD supports no user defined chars or icons. So I made
>     drv_generic_text_real_defchar do nothing or should it point to NULL?
set it to NULL

> 3. Char values below 0x20 are controll data (goto, reset, dim...).
>     Should they be filtered (or replaced by blanks) in the write function?
Yes, you could do so.

> 4. Do I have to add drv_generic_parport_hardwire_ctrl for D0-7?
no, because D0..D7 are data lines, the wiring stuff is for control lines only.

> 5. What's the meaning of the first three arguments (val1,val2,dir) of
>     drv_generic_text_bar_add_segment and how must they to be 'constructed'?
Have a look at the drv_WincorNixdorf.c, which is a text-mode driver with no support for user-defined characters. There 
is a "workaround" for such displays, they use a regular character to construct bars (a '*' in the case of WincorNixdorf)


> 6. Should I delete or comment out all the icon lines?
Yes, probably.


if you have further questions, just let me know!


regards, Michael

-- 
Michael Reinelt <mi...@re...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781