Re: [lcd4linux] Is it possible to use LCD4Linux with a HD44780-compatible LCD, which is attached to the GPIO pins of a Raspberry Pi?

[Prof. D. C. B. <wol...@gm...>]

Hi all,

It is also my experience that the GPIO pins of the Raspberry Pi are
very simple to access.

It is quite popular [1][2] to connect HD44780 compatible LCDs via
these GPIOs and access them via LCDproc [3]. The drawback (in my
opinion) of LCDproc is that the configuration is not very
user-friendly compared with LCD4Linux.

In the last hours I did some investigation about options to emulate
the parallel port via the GPIO pins of the Raspberry Pi. But up to now
I found no existing and promising solution.

Another option is to implement a LCD4Linux GPIO driver for the
Raspberry, but I think my skills in C are not good enough.

A the moment I think I will code a tiny script like this one [4] to
get the output I want.

Best Regards
   Christian

[1] http://www.boeeerb.co.uk/pi-lcd/
[2] https://learn.adafruit.com/drive-a-16x2-lcd-directly-with-a-raspberry-pi/
[3] http://lcdproc.sourceforge.net/docs/current-user.html#hd44780-raspberrypi
[4] https://learn.adafruit.com/drive-a-16x2-lcd-directly-with-a-raspberry-pi/python-code



2014-08-31 20:49 GMT+02:00 Johan Swenker <joh...@xs...>:
> Hi,
>
> I would like to disagree. Even though lcd4linux is older then the raspberry,
> the GPIO-pins of the raspberry are
> as versatile as the parallel port of yesteryear.
>
> Using a search engine you will find several people who have connected an LCD
> to the RPi. For example:
> https://learn.adafruit.com/downloads/pdf/drive-a-16x2-lcd-directly-with-a-raspberry-pi.pdf
> They even have software, though incompatibel with lcd4linux.
>
> The same search engine will also be able to find you several LCDs with an
> I2C interface (implemented by
> adding a microcontroller board to the LCD). Among them:
> http://www.bitwizard.nl/wiki/index.php/SPI_LCD
>
> Regards Johan
>
>> Hello Christian,
>>
>> as lcd4linux is a lot older than raspberry, I don't think that it will
>> work, at least not out-of-the-box.
>>
>> back in the "good old days" the only GPIO-like thing on a PC used to be
>> the parallel port, and thats what a low-level
>> driver exists for (drv_generic_parport), which uses either extremely old
>> school io instructions, or ppdev.
>>
>> As I have absolutely no idea how GPIOs are controlled on a raspberyy, I
>> cannot advice you how to implement it.
>>
>> maybe using some kind of i2c-to-parallel chip could work, too.
>>
>>
>>
>> regards, Michael
>>
>> Am 2014-08-31 13:18, schrieb Prof. Dr. Christian Baun:
>>>
>>> Hi all,
>>>
>>> is it possible to use LCD4Linux with a LCD (HD44780 compatible
>>> controller), which is attached to the GPIO pins of a Raspberry Pi?
>>>
>>> Has anybody here an example for a lcd4linux.conf file, which makes use
>>> of the Raspberry Pi GPIO pins?
>>>
>>> Best Regards
>>>      Christian
>>>
>>>
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>>
>