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[Lcdproc] fcntl for lcd serializer

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  • From: loosen at (Bob van Loosen)
  • Subject: [Lcdproc] fcntl for lcd serializer
  • Date: Tue, 04 Nov 2008 17:20:16 +0100


I've got an hd44780 connected to a PIC18F4550 which is connected to usb,
it emulates a cdc device, which is sort of like a serial port, it uses
the lcd serializer protocol.
I got it to work with my own software, but not with a standard lcdproc.

I noticed two problems:

Lcdproc initializes the display to 8 bit mode by default, I'm using 4
bit mode but since the standard lcd serializer initializes the display
anyway lcdproc shouldn't have to do any initialization.

Lcdproc doesn't set the serial port to blocking mode, for some reason
the cdc device defaults to non-blocking mode and because it's not very
fast and doesn't have a very large buffer it didn't work.
Adding fcntl(p->fd, F_SETFL, 0); in hd_init_serial sets the port to
blocking mode.

Lcdproc is a great piece of software, keep up the good work.


Bob van Loosen.

  • [Lcdproc] fcntl for lcd serializer, Bob van Loosen, 11/04/2008

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