Interfacing with Arduino I2C LCD

[n0yox]

I am trying to make this code work with a 16F629A and all I get is a blinking back light with the modified code below.I am probably missing something simple?

Thanks,

; Filename : Test_LCD_PCF8574.pbp
; Author : Darrel Taylor
; Created : Mon Feb 24 2014
; Processor : 16F629A
; Compiler : PicBasic Pro 3.0.6.x or higher
; Description : Uses PCF8574 Port expander to interface with HD44780 LCD
;

;----[16f629A Hardware Configuration]-------------------------------------------
#config
__config _INTOSC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _LVP_OFF & _CP_ON & _BODEN_OFF
#endconfig



;----[Aliases]------------------------------------------------------------------
SDA var porta.7
SCL var porta.6
;----[Initialize Hardware]------------------------------------------------------
CMCON = 7 'CHANGES PORTA TO DIGITAL
;----[Setup LCD using PCF8574 Port Expander]------------------------------------
LCD_Addr CON $7E
INCLUDE "LCD_PCF8574.pbp" ; Include LCD module for PCF8574

;----[Variables]----------------------------------------------------------------
LoopCount VAR BYTE
CustChar VAR BYTE

;----[Program Start]------------------------------------------------------------
Backlight = 0 ; Turn on LCD Backlight
ARRAYWRITE LCD_Buff,[" LCD PCF8574"] : LCD_WriteBuff
LoopCount= 0

;----[Custom Characters]-(Jumping Jacks)----------------------------------------
ARRAYWRITE LCD_Buff,[$FE,$40,$00,$04,$0A,$04,$0E,$15,$0A,$11]:LCD_WriteBuff ' #0
ARRAYWRITE LCD_Buff,[$FE,$48,$00,$04,$0A,$04,$1F,$04,$0A,$0A]:LCD_WriteBuff ' #1
ARRAYWRITE LCD_Buff,[$FE,$50,$04,$0A,$15,$0E,$04,$0A,$0A,$00]:LCD_WriteBuff ' #2

;----[Main Program Loop]--------------------------------------------------------
Main:
ARRAYWRITE LCD_Buff,[$FE,$C0,"Count = ",DEC LoopCount," "] : LCD_WriteBuff
PAUSE 200
LoopCount = LoopCount + 1

CustChar = LoopCount//3 ; Jumping Jacks Sequence
ARRAYWRITE LCD_Buff,[$FE,$C0,CustChar] : LCD_WriteBuff
GOTO Main

[n0yox]

I did delete these two lines

ARRAYWRITE LCD_Buff,[" LCD PCF8574"] : LCD_WriteBuff

ARRAYWRITE LCD_Buff,[$FE,$C0,"Count = ",DEC LoopCount," "] : LCD_WriteBuff

and Change this line

ARRAYWRITE LCD_Buff,[$FE,$C0,CustChar] : LCD_WriteBuff ' $C0 was $9D

[richard]

16F629A ?
might you mean 12f629 ?

if so you need to set the " lcd " pins to digital

[n0yox]

Sorry, I should have said 16F628A. I did set my pins as digital? I want to display data from my program but that seems far away at this point?? I cut the program down to the below lines and I get a custom character and a blinking cursor the backlight stays on. I guess that is progress ?

Thank You!

;----[16f628A Hardware Configuration]-------------------------------------------
#config
__config _INTOSC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _LVP_OFF & _CP_ON & _BODEN_OFF
#endconfig


SDA var porta.7
SCL var porta.6
;----[Initialize Hardware]------------------------------------------------------
CMCON = 7 'CHANGES PORTA TO DIGITAL
;----[Setup LCD using PCF8574 Port Expander]------------------------------------
LCD_Addr CON $7E
INCLUDE "LCD_PCF8574.pbp" ; Include LCD module for PCF8574

ARRAYWRITE LCD_Buff,[$FE,$50,$04,$0A,$15,$0E,$04,$0A,$0A,$00]:LCD_WriteBuff ' #2


Main:

GOTO Main

[richard]

there is more info here . note the slightly differing versions of the include
INCLUDE "LCD_PCF8574.pbp" ; Include LCD module for PCF8574
INCLUDE "LCD_PCF8574a.pbp" ; Include LCD module for PCF8574

http://support.melabs.com/threads/10...hlight=PCF8574
http://support.melabs.com/threads/10...hlight=PCF8574
ps
LCD_Addr CON $7E is way different to addr used in above threads

[n0yox]

Richard thank you for your help.

I have read most of the threads but will read them again. I will find and download both version of the include. On Arduino this is the Initialization for my display the 3F turns into 7E when you shift the bits one to the left.

"LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE)"

I have used serial lcd displays in the past with no issues. So far I am not a fan of this i2c version. I think someone is missing a market for easy to use i2c displays?

Thanks again!

[richard]

"LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE)"

interpreted as [( 7bit_addr, EN, RW, RS, D4, D5, D6, D7, Backlight, POLARITY) ]

the PCF8574 datasheet indicates the 7bit addr range is 0x20--0x27

0x3f is not valid afaik.


default with a0:2 open = 7bit_addr of 0x27 , pbp addr would be $4e