lcd4linux-users

[lcd4linux] serial HD44780

[Ognjen B. <og...@ma...>]

Hi all,

I want to use a HD44780 2x24 LCD display with a linux box, but without
using up the parallel port (still use it for the
printer). I was wondering what other methods are there of connecting the
displays to the computer.

I know of the USB method, but was wondering of there are any other
methods. I googled about and came across
a project knows as LCD serialiser (project page:
http://www.mindspring.com/~tcoonan/lcd.html).

This seemed to fit my needs except that:

a) I do not have the required components - So does anyone know where I
can buy pre-assembled versions of these boards? I can build it, its just
that I would need to purchase quite a bit of kit (e.g. PIC programmer)
in order to do it.

b) There is no mention on the lcd4linux wiki about supporting this
project in particular (although there are references to serial-based
lcd's such as the lcd terminal emulator). Is there support for this
project in lcd4linux and if not, is it planned at all? looking at the
project it seems that the commands sent are the same (raw) command you
send to a hd44780 on a parallel port, except that its sent down a serial
link.

So is their any support for this? and if not, can anyone recommend an
alternative method of connecting lcd's to the computer.

Cheers.

Re: [lcd4linux] serial HD44780

[paul k. <pau...@xs...>]

Hi Ognjen,

Serial port connection is not currently support. The only alternative 
connection method for the HD44780 display is an i2c interface. I know 
there is kernel support for i2c over parallel port, but I am not sure if 
it is available over serial port. I think it should be possible since 
you need to control only 3 wires. Nevertheless you need additional 
hardware to make it work,  a single pcf8574 is required.

kind regards,

Paul

Ognjen Bezanov wrote:

>Hi all,
>
>I want to use a HD44780 2x24 LCD display with a linux box, but without
>using up the parallel port (still use it for the
>printer). I was wondering what other methods are there of connecting the
>displays to the computer.
>
>I know of the USB method, but was wondering of there are any other
>methods. I googled about and came across
>a project knows as LCD serialiser (project page:
>http://www.mindspring.com/~tcoonan/lcd.html).
>
>This seemed to fit my needs except that:
>
>a) I do not have the required components - So does anyone know where I
>can buy pre-assembled versions of these boards? I can build it, its just
>that I would need to purchase quite a bit of kit (e.g. PIC programmer)
>in order to do it.
>
>b) There is no mention on the lcd4linux wiki about supporting this
>project in particular (although there are references to serial-based
>lcd's such as the lcd terminal emulator). Is there support for this
>project in lcd4linux and if not, is it planned at all? looking at the
>project it seems that the commands sent are the same (raw) command you
>send to a hd44780 on a parallel port, except that its sent down a serial
>link.
>
>So is their any support for this? and if not, can anyone recommend an
>alternative method of connecting lcd's to the computer.
>
>Cheers.
>
>
>
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>  
>

Re: [lcd4linux] serial HD44780

[Ognjen B. <og...@ma...>]

But will serial connections be supported in future?

What exactly is I2C, I know it is a serial bus, but where is it? Is
there a I2C connector on my motherboard? or does it work using the
serial/parallel ports. Where can I find more information regarding how
to connect LCD displays
to the I2C bus.

Thanks

paul kamphuis wrote:

> Hi Ognjen,
>
> Serial port connection is not currently support. The only alternative
> connection method for the HD44780 display is an i2c interface. I know
> there is kernel support for i2c over parallel port, but I am not sure
> if it is available over serial port. I think it should be possible
> since you need to control only 3 wires. Nevertheless you need
> additional hardware to make it work,  a single pcf8574 is required.
>
> kind regards,
>
> Paul
>
> Ognjen Bezanov wrote:
>
>> Hi all,
>>
>> I want to use a HD44780 2x24 LCD display with a linux box, but without
>> using up the parallel port (still use it for the
>> printer). I was wondering what other methods are there of connecting the
>> displays to the computer.
>>
>> I know of the USB method, but was wondering of there are any other
>> methods. I googled about and came across
>> a project knows as LCD serialiser (project page:
>> http://www.mindspring.com/~tcoonan/lcd.html).
>>
>> This seemed to fit my needs except that:
>>
>> a) I do not have the required components - So does anyone know where I
>> can buy pre-assembled versions of these boards? I can build it, its just
>> that I would need to purchase quite a bit of kit (e.g. PIC programmer)
>> in order to do it.
>>
>> b) There is no mention on the lcd4linux wiki about supporting this
>> project in particular (although there are references to serial-based
>> lcd's such as the lcd terminal emulator). Is there support for this
>> project in lcd4linux and if not, is it planned at all? looking at the
>> project it seems that the commands sent are the same (raw) command you
>> send to a hd44780 on a parallel port, except that its sent down a serial
>> link.
>>
>> So is their any support for this? and if not, can anyone recommend an
>> alternative method of connecting lcd's to the computer.
>>
>> Cheers.
>>
>>
>>
>> -------------------------------------------------------
>> This SF.Net email is sponsored by the 'Do More With Dual!' webinar
>> happening
>> July 14 at 8am PDT/11am EDT. We invite you to explore the latest in dual
>> core and dual graphics technology at this free one hour event hosted
>> by HP,
>> AMD, and NVIDIA.  To register visit http://www.hp.com/go/dualwebinar
>> _______________________________________________
>> Lcd4linux-users mailing list
>> Lcd...@li...
>> https://lists.sourceforge.net/lists/listinfo/lcd4linux-users
>>
>>
>>  
>>
>
>

Re: [lcd4linux] serial HD44780

[paul k. <pau...@xs...>]

Ognjen Bezanov wrote:

>But will serial connections be supported in future?
>
>  
>
Only if someone finds the need for it, and does all the work. Just like 
Luis and I need the I2C support, so we did the work for it.

>What exactly is I2C, I know it is a serial bus, but where is it? Is
>there a I2C connector on my motherboard? or does it work using the
>serial/parallel ports. Where can I find more information regarding how
>to connect LCD displays
>to the I2C bus.
>
>  
>
I doubt if there is een i2c connector on your mainboard. I have a VIA 
EPIA mainboard, which has one. But most mainstream PC mainboards don't 
have one.
I2C is a 2-wire (clock and data line) serial bus. Mainly intended to 
interface with peripheral devices (NVRAM, digital potmeters etc.)
In 99-100% of the cases, to interface with user hardware (like an lcd 
display) a PCF8574 chip is used. This is a I2C to 8-bit IO expander.
datasheet can be found here:
http://www.semiconductors.philips.com/cgi-bin/pldb/pip/pcf8574p

I know there is kernel support to emulate i2c over the parallel port. 
But I am not sure if it is supported to do the same thing over serial 
port. (theoretically it is possible)

Good luck,

Paul