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[Lcdproc] I2C PCF8754 LCD


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  • From: swp AT webworm.co.uk (Stuart Poulton)
  • Subject: [Lcdproc] I2C PCF8754 LCD
  • Date: Tue Mar 14 16:10:02 2006

Hi,

I'm trying to get a pled display, connected by i2c with a pcf8574

Details as follows

Display: http://www.crystalfontz.com/products/CFAP1602B/index.html
Circuit in use: http://no.spam.ee/~tonu/i2clcd.xhtml

I know this is slightly different to the recommended i2c pcf8754 circuit,
but I think it should still work, maybe a tweak required to the control line
definitions in hd44780-i2c.c file.

Mod as follows

#define RS 0x10
#define RW 0x40
#define EN 0x20
#define BL 0x80

instead of

#define RS 0x10
#define RW 0x20
#define EN 0x40
#define BL 0x80

I realise this is a realfudge and probably wrong.....

hd44780 driver section is as follows

[HD44780]
ConnectionType=i2c
Device=/dev/i2c-0
Port=0x38
Backlight=yes
Size=16x2
DelayBus=true
DelayMult=1
Keypad=no

Running LCDd gives

Server forking to background
Listening for queries on 127.0.0.1:13666
HD44780: I2C: Using device '/dev/i2c-0' and address 3085089190 for a
/dev/i2c-0
HD44780: I2C: i2c write data 3 to address 56 failed: Function not
implemented
Key "Escape" is now reserved in exclusive mode by client [-1]
Key "Enter" is now reserved in shared mode by client [-1]
Key "Up" is now reserved in shared mode by client [-1]
Key "Down" is now reserved in shared mode by client [-1]
screenlist_switch: switched to screen [_server_screen]

The kernel can see the pcf8574,

pbx root # ./i2cdetect 0
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0.
I will probe address range 0x03-0x77.
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: XX XX XX XX XX XX XX XX XX XX XX XX XX
10: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX
30: XX XX XX XX XX XX XX XX 38 XX XX XX XX XX XX XX
40: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX
50: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX
70: XX XX XX XX XX XX XX XX




Anyone able to give some pointers as how I might get some info onto the
display ?

Regards

Stuart





  • [Lcdproc] I2C PCF8754 LCD, Stuart Poulton, 03/14/2006

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