Parallel port on beagle

Hi, I’m trying to work with a display using lcd4linux.
I have 4 gpio to manage the data bits (4 bits) and all the hardware done. My display is compatible with the HD44780 driver.
I read the documentation about configuration and it says that I need a parallel port on /dev (/dev/parports/*).
I read a lot more and I found something about ppdev-module.

I know that the beagle doesn’t come with parallel port, but: there’s a way to cheat the display?.

I need to know if I could use lcd4linux for my purpose.

thank’s…

daniel.

Hi Daniel,

Hi, I'm trying to work with a display using lcd4linux.
I have 4 gpio to manage the data bits (4 bits) and all the hardware done. My
display is compatible with the HD44780 driver.
I read the documentation about configuration and it says that I need a
parallel port on /dev (/dev/parports/*).
I read a lot more and I found something about ppdev-module.
I know that the beagle doesn't come with parallel port, but: there's a way
to cheat the display?.
I need to know if I could use lcd4linux for my purpose.
thank's...

You could write a driver which uses the parport API but which toggles
some GPIOs instead.

I did this on a gumstix for programming AVRs. I crosscompiled some
host software (avrdude and avrisp) which expected to talk to a
parallel port.
You can take a look at my code over here:
http://gitorious.org/gumstix-oe/mainline/blobs/org.openembedded.dev/recipes/robostix-module/files/robostix.c
Search for PPRSTATUS and PPRCONTROL, PPWCONTROL, PPRDATA, PPWDATA,
PPCLAIM, PPRELEASE, PPDATADIR ioctls.
These were the ioctls I needed to implement that the AVR programmers
used. You may need a slightly different set for lcd4linux.

There is some documentation for these over here:
http://people.redhat.com/twaugh/parport/html/x623.html

Dave Hylands

Hi Daniel,

You can try to use LCDProc (http://lcdproc.org/) plus FT245BM Linux
driver (http://sourceforge.net/projects/ftdi-usb-ft245/). LCDProc has
support for HD44780 (http://lcdproc.sourceforge.net/docs/lcdproc-0-5-3-
user.html#hd44780-howto).

Cheers,
Max.

Thank you.

I’ll be working on this.