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[Lcdproc] [Patch] Experimental hd44780 wiring using FreeBSD's ppi device


Chronological Thread 
  • From: mail AT andrestrapanotto.com.ar (Andres Trapanotto)
  • Subject: [Lcdproc] [Patch] Experimental hd44780 wiring using FreeBSD's ppi device
  • Date: Tue Mar 29 14:20:02 2005

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~ Hi Markus! I haven't FreeBSD and I didn't know that there is ppi
device.
~ For Linux instead, I've written a port.c and modified the port.h
to support ppdev device. You can take a look to it in the "ppdev
support" mail at March 9.
~ Perhaps you can add your contribution to them and make ppi
available to any driver ;)
~ Best regards, Andrés Trapanotto.

Markus Dolze wrote:

| Hello,
|
| with my limited C knowledge I played a bit with FreeBSD's ppi
| device. From the man page:
|
| "The ppi driver provides a convenient means for user applications
| to manipulate the state of the parallel port, enabling easy
| low-speed I/O operations without the security problems inherent
| with the use of the /dev/io interface."
|
| I wrote an additional wiring scheme using the ppi device and its
| ioctl commands. The driver uses winamp style hardware wiring.
| Although the ppi code adds some latency to the parallel port it is
| currently working fine with my display (Displaytech 162C).
|
| It would have been best to replace or add the ppi device instead of
| outb() and inb() calls in port.h, but it requires rewriting of the
| lcdproc drivers because ppi has different calls for control and
| data ports. The hd44780 driver currently does only have the outb()
| call which is passed the port to access.
|
| So if anyone ever writes a replacement for direct port access, this
| wiring driver demonstrates how it can work on FreeBSD. The driver
| is therefore not meant to be included in the main lcdproc sources.
|

- --
Técnico Andrés Trapanotto
INSTITUTO NACIONAL DE TECNOLOGÍA INDUSTRIAL
Centro de Investigación Telecomunicaciones, Electrónica e Informática
Teléfono (54 11) 4724 6300 Interno 6362
mail AT andrestrapanotto.com.ar
___________________________________________
0800 444 4004 | www.inti.gov.ar
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