Tobi’s Corner

Here I describe how to interface a Character LCD based on HD47780 or compatible controllers.

Ext IF	#	LCD	#
D0	1	D0	7
D1	2	D1	8
D2	3	D2	9
D3	4	D3	10
D4	5	D4	11
D5	6	D5	12
D6	7	D6	13
D7	8	D7	14
A0	9	RS	4
A1	10	E	6
A2	11	RW	5
A3	12	–
+5V	13	VDD	2
/CS	14	–
/RD	15	–
/WR	16	–
/INT	17	–
GND	18	VSS	1
		Vo (contrast)	3

Vo … connect a 10k poti between VDD and GND and the wiper to Vo.

For a better bus interface I have to look on the function of the /CS line in more detail so that the LCD doesn’t get disturbed by misc. data.
To get some data onto the display I modified diag.c the kernel module that is used by OpenWRT to set the Router’s LEDs and to fetch some keys. diag.c can be found in: /location_where_you_unziped_openwrt/target/linux/packages/diag/src/. I added a own /proc entry called extif. And so I was able to display data that way:

echo “iHello OpenWRT :-)” > /proc/diag/extif

The “i” is only there to tell the module to initialize the display first.

My Module

Next step will be that i write a module on my own that handels everything –> Read here more about the module…

Tags: LCD, Module, OpenWRT

This entry was posted on Thursday, December 7th, 2006 at 03:48 and is filed under jukebox. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.