Connecting a LCD to the WL500g

[gryle]

Hi

Here's an image of my work in progress

This is a HD44780 LCD connected to the parallel port of the ASUS WL-500g.
I'm powering it from the USB port.
I'm using OpenWRT as the firmware and lcdproc as the software to drive the LCD.
lcdproc was patched to use ppdev (/dev/parports/0) with the HD44780 driver instead of using inb/outb x86 instructions to communicate with the parallel port.
I also made a parallel port driver for the asus so that the binary 2.4.5 modules from the asus firmware aren't needed anymore.
I'll release the source code of the parallel port driver and the patch to lcdproc soon

[Oleg]

Wow. Good work. The most important tihng for everyone is the parport_splink code.
Have you checked it with LPT printer?

[gryle]

No Oleg, the printer I have near by is USB.
Writes do the data and control lines should be working. Reads from status lines, I hope so
I've uploaded the source code to http://pwp.netcabo.pt/0246517002/parport_splink.c if you want to take a look.

Don't include the parport_pc on the kernel or as a module, because if CONFIG_PARPORT_PC or CONFIG_PARPORT_PC_MODULE are defined lp.o and ppdev.o will use inline functions from parport_pc and you'll get kernel Oops (check include/linux/parport.h). I lost lots of time debugging this

Do you know if it would be possible to use an IRQ or modes other than PARPORT_MODE_PCSPP? I looked at the Asus binary module and they seem to try to free irq 2 on module cleanup... That irq is being used by the USB controller on my Asus.

[Oleg]

Сообщение от gryle

No Oleg, the printer I have near by is USB.
Writes do the data and control lines should be working. Reads from status lines, I hope so
I've uploaded the source code to http://pwp.netcabo.pt/0246517002/parport_splink.c if you want to take a look.

Don't include the parport_pc on the kernel or as a module, because if CONFIG_PARPORT_PC or CONFIG_PARPORT_PC_MODULE are defined lp.o and ppdev.o will use inline functions from parport_pc and you'll get kernel Oops (check include/linux/parport.h). I lost lots of time debugging this

Do you know if it would be possible to use an IRQ or modes other than PARPORT_MODE_PCSPP? I looked at the Asus binary module and they seem to try to free irq 2 on module cleanup... That irq is being used by the USB controller on my Asus.

Yes, the IRQ pin is physically connected to one of the GPIO pins, which can be enabled to generate IRQs. I've not checked for details yet. And yes, they're sharing IRQs. It also, possible to use other modes, including EPP, ECP, whatever. It's selected by accessing it at 0xbf800410 (so, in standard way +0x400).
Let me know if you need other info.

[QuarterPounder]

hello!
i'm very interested in this, because i had the same idea.
i will test all the shit if you provide everything.
i have a gfx-lcd, but it's no problem, because i have found lcdproc-patches for it.
i will code an alternative to lcdproc, because it is not very effective for glcds.

ps: i still need a good buildroot with a g++, i'm too stupid to compile my own :-( .

[Sickboy]

Gryle,

I would love to take a look at your LCDproc HD44780 ppdev driver mods. I have been trying to figure this out for a while.

Any chance you could post the code somewhere or maybe email me with it? (admin at purecom.com)

Thanks!

[Randale91]

Hello,

does someone have a simple makefile for this parport_splink.c file ?
I cant get the it working..
Something must be missing...
Error during compilation:

In file included from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/sched.h:15,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/mm.h:4,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/pagemap.h:10,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/io.h:15,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/parport_pc.h:4,
from parport_splink.c:14:
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/timex.h:171: field `time' has incomplete type
In file included from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/sched.h:18,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/mm.h:4,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/pagemap.h:10,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/io.h:15,
from /opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/linux/parport_pc.h:4,
from parport_splink.c:14:
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:31: parse error before "wait_queue_head_t"
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h: In function `sema_init':
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:65: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:66: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:67: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h: In function `down':
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:93: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h: In function `down_interruptible':
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:104: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h: In function `down_trylock':
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:114: dereferencing pointer to incomplete type
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h: In function `up':
/opt/brcm/hndtools-mipsel-uclibc-0.9.19/include/asm/semaphore.h:185: dereferencing pointer to incomplete type

and so on.....

Thanks in advance.

Gabriel

[KillerOPS]

look here on how to control the parallel port of that thing. The only problem is that it isn't working with oleg's firmware (not sure which one) because you can't remove the lp.o module without crashing the router. However, on OpenWrt works quite good.
Maybe a patch from oleg?

Anyway, here is the link:
http://www.sephail.net/projects/openwrt/

[skynet]

Maybe I cheated
I used a atmega8 micro to handle the LCD and 4x4 keypad. It talks either serial (uart to uart so no rs232 tranciever) or I2C using 2 of the gpio lines (on boards with uart. A few bugs left with the I2C... There is a very low part count (one ceramic resonator with built in caps, 2 resistors to drop the 5v down to 3.3, the avr, backlight current limiting resistor, pot for contrast, and a 5v regulator)

If anyone has a like project (maybe with a cheaper pic) PM me.

[poliveira1978]

what was your openwrt version? could u provide some king of guide to do the install?

[macsat]

I've made a bunch of OpenWrt tutorials here:
http://www.macsat.com/macsat/content/category/3/14/30/