I2C lcd ( arduino ) with PICBASIC, help

[EarlyBird2]

Let me know when you have a replacement. I am confident that we can get this to work between us. You do the testing and I will help with the programing.

I would do it all but I do not have the hardware anymore as I went over to touch screen PLCs. I am more interested in touch screen GLCD solutions based on a PIC (Amicus18 for example) which I need the hardware for.

[iw2fvo]

Thanks Steve,
I do appreciate your help. I will tell you as soon as I have the new dispaly in my hands.
Ambrogio

[iw2fvo]

Hi Steve,
I received the new display just now.
It is equipped with the PCF 8574T.
It is connected to the QC2004A display in the following way:

pin_4 p0 > RS
pin_5 p1 > RW
pin_6 p2 > enable
pin_7 p3 > Backlight
pin_9 p4> data4
pin_10 p5 > data5
pin_11 p6 > data6
pin_12 p7 > data7

It is different wrt the one I had before: it has a different connections between the PCF and the LCD.
I will be ready for testing tomorrow or monday: please suggest me what trials to do just to start.
Thanks for all
Ambrogio

[EarlyBird2]

We start with Darrel's routine for PBP3 and make changes for your LCD pin setup and PBP2.x

http://support.melabs.com/threads/98...F8574-20x4-LCD

[iw2fvo]

Steve,
the point is that I do not have PBP_3.
My pbp is 2.50 B.
No arraywrite or read, no usercommand ... are available to me .
Thanks
Ambrogio

[EarlyBird2]

Steve,
the point is that I do not have PBP_3.
My pbp is 2.50 B.
No arraywrite or read, no usercommand ... are available to me .
Thanks
Ambrogio

Yes the arraywrite command has to be handled differently in pbp2.5.

Arraywrite loads the LCD_Buff you need to replace Arraywrite with a routine that loads what you want displayed on the LCD into LCD_Buff.

For example
LCD_BuffLen = 4
LCD_Buff.0 = "T"
LCD_Buff.1 = "e"
LCD_Buff.2 = "s"
LCD_Buff.3 = "t"
LCD_WriteBuff

Just to give you an idea as I think this is how it works but obviously I have not tested it as only you have the hardware.

Also johncouture's LCD has the same pins as your's (check it) so his modified programs are the ones you need to use.

This is the first step more issues could be thrown up. I am expecting to enjoy the ride (voyage of discovery) and hopefully get it working.

[iw2fvo]

Steve,
sorry for not having reply soon because of " family duty ".
I wrote this small program and I am able to control Backlight :

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL
DEFINE I2C_SLOW 1
C VAR portd.3 ' S_CLOCK
D VAR portd.2 ' S_DATA
ADDR VAR BYTE
ADDR = %01001110 ' dec 78 , hex 4E
CMD VAR BYTE
LCD_CMD VAR BYTE
E VAR LCD_CMD.BIT2
RS VAR LCD_CMD.BIT0
E=0:RS=0
LCD_CMD = 0
PAUSE 1000

MAIN:

I2CWRITE D, C, ADDR, [%00000000] ' bck_lt= off
PAUSE 200
I2CWRITE D, C, ADDR, [%00001000] ' bck_lt=on
PAUSE 200

GOTO MAIN

The I2C address is new.
Now, my LCD has 20 chrs X 4 lines.
The PCF controls the LCD using the upper four bits of its output port.
I have to initialize the LCD in four bit mode , four lines at the required PCF port pins.
How could I do that ?
Thanks
Ambrogio