Re: [Lcd-linux] Introducing the LCD-Linux project
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From: Geert U. <ge...@li...> - 2010-07-26 20:08:50
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On Thu, Jul 22, 2010 at 13:38, Geert Uytterhoeven <ge...@li...> wrote: > On Thu, Jul 22, 2010 at 13:21, Alan Cox <al...@lx...> wrote: >> On Wed, 21 Jul 2010 14:57:54 +0200 >> Mattia Jona-Lasinio <mat...@gm...> wrote: >>> this is to introduce the LCD-Linux project (http://lcd-linux.sourceforge.net/), >>> a kernel level implementation of a VT102 terminal emulator, optimized for small >>> alphanumeric and graphic displays. >> >> The kernel already has a console and that provides an abstract >> implementation that is used for everything from text mode displays to vga >> to assorted accelerated hardware platforms. >> >> Why do we need a VT102 as well ? >> >>> functions. A solution is therefore to provide a sort of minimal terminal >>> emulation in kernel space, that can be accessed through the standard character >>> device interface. In this way the problem of the display management is reduced >> >> If you use the existing kernel console interfaces then you don't need to >> worry about vt102 v console or having two terminal emulations running. > > Indeed, the kernel already has the console abstraction. > > I wrote a LCD console driver (for a HD44780 connected to the parallel > port) using > the standard console abstraction several years ago. As it used the standard > console abstraction, it supported multiple virtual consoles and co-operated with > the VGA text console out-of-the-box. Just use ALT-Fx to switch between different > VCs on the LCD or on VGA. > > I never published the code, though. Will do so tonight when I get back > to the machine that holds the code ;-) And so I did, to prevent it from being lost for mankind: http://users.telenet.be/geertu/Download/hd44780.tar.gz This is a Linux console driver for a HD44780 LCD connected to a PC-style parallel port. It supports both 4-bit and 8-bit interface mode. The code was developed and used with a 20x4 LCD connected to the parallel port of a standard PC and a CHRP LongTrail PowerPC box, with Linux kernel 2.2 (early development) and 2.4, from 2000 until 2004. There's no guarantee it will work with more recent kernels. The console driver has a comment suggesting to use a 20x4 window on an 80x25 virtual screen, but this has never been implemented. It consists of 4 modules: - hd44780: Mid-level HD44780 LCD driver, handling the HD44780 commands [kernel, user] - parlcd: Low-level HD44780 driver, defining how to talk to a HD44780 LCD connected to a PC-style parallel port [kernel, user] - lcdcon: Standard Linux console driver for a HD44780 LCD [kernel] - play: Interactive test program to talk to the HD44780 or to the raw parallel port [user] Modules marked [kernel] are used inside the Linux kernel only. Modules marked [user] are used with the userspace test program. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li... In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds |