I2C lcd ( arduino ) with PICBASIC, help

[iw2fvo]

Thanks to all of you for the assistance.
What is the dig modifier please ?
Thnaks
Ambrogio

[pedja089]

From manual:
DIG returns the value of a decimal digit. Input the digit number (0 – 9, with 0 being the rightmost digit). DIG returns the value of the decimal digit that you specified. DIG is commonly used to distill BCD digits from numeric values and to isolate single digits for display on seven-segment LCD.
B0 = 123 ' Set B0 to 123
B1 = B0 DIG 2 ' Sets B1 to 1 (digit 2 of 123)

[iw2fvo]

That is clear to me now.
Thanks
Ambrogio

[EarlyBird2]

Ambrogio

I am working on the program by adding commands as you can see in the picture.



Let me know when you are ready.

[iw2fvo]

Steve, very good result !
I think It will help a lot of people too .
I am wait to receive the item ( about 20 days ).
Could you please post the code : I will start to study it .
Thanks
Ambrogio

[EarlyBird2]

Steve, very good result !
I think It will help a lot of people too .
I am wait to receive the item ( about 20 days ).
Could you please post the code : I will start to study it .
Thanks
Ambrogio

Here it is. This is a simple test program for PBP2.5 or lower. Anything you do not understand please ask. The next step is to include the command selection inside the LCD_WRITE subroutine.

'****************************************************************
'*  Name    : I2CLCD.BAS                                                                 
'*  Author  : Steve Earl                                                                                  
'*  Notice  : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS]                     
'*          : All Rights Reserved                                                                         
'*  Date    : 17/07/2014                                                                                
'*  Version : 1.0                                                                                            
'*  Notes   : Serial I2C LCD using PBP 2.5                                                       
'*          : PCF8574T I2C port expander 20x4 LCD         
'****************************************************************

define OSC 40     ' set the correct speed here!!
'DEFINE I2C_SLOW 1
SDA         VAR PORTD.2       ; I2C Data pin
SCL         VAR PORTD.3       ; I2C Clock Pin
LCD_Addr CON 78               ; PCF8574T address

'LCD_BuffSize    CON 30
'LCD_Buff        VAR BYTE[LCD_BuffSize]
'LCD_BuffAddr    CON EXT : @LCD_BuffAddr = _LCD_Buff
'LCD_BuffLen     VAR WORD        ; Length of data in buffer
LCD_Data        VAR BYTE        ; Data to Send to LCD
LCD_Byte        VAR BYTE        ; Nibbles to Send
LCD_RS          VAR LCD_Byte.0  ; Register Select bit
LCD_RW          VAR LCD_Byte.1  ; Read/Write bit
LCD_E           VAR LCD_Byte.2  ; Enable bit
LCD_BackLight   VAR LCD_Byte.3  ; Backlight 1=ON
LCD_WriteMode   VAR BYTE        ; 1=LowNibble, 2=HighNibble, 3=Both
'LCD_CommandMode VAR BIT         ; Indicates next byte is a command
LCD_Byte2       VAR BYTE        ; Same nibble without E bit
'LCD_Idx         VAR BYTE
seconds var byte
minutes var byte
hours   var byte

Init:
;----[Initialize the LCD]-------------------------------------------------------
PAUSE 250                           ; LCD Power-on delay
LCD_Backlight = 1                   ; Backlight On
LCD_RW = 0                          ; Write to LCD
LCD_RS = 0                          ; Command Register

LCD_WriteMode = 1                   ;-- Low Nibbles only
LCD_Data = 3                        ; Software Reset 3 times
gosub LCD_Write : PAUSEUS 6000
gosub LCD_Write : PAUSEUS 1000
gosub LCD_Write : PAUSEUS 1000

LCD_Data = 2                        ; Start 4-bit mode
gosub LCD_Write : PAUSEUS 1000

LCD_WriteMode = 3                   ;-- Both Nibbles
LCD_Data = $28 : gosub LCD_Write    ; Function Set, 4-bit, 2-line, 5x7
LCD_Data = $0C : gosub LCD_Write    ; Display ON
LCD_Data = $01 : gosub LCD_Write    ; Clear Screen
PAUSE 50
LCD_Data = $06 : gosub LCD_Write    ; Entry Mode
PAUSE 2                             ; Let command finish
LCD_RS = 1                          ;Switch to Data 
;Print Static Background to LCD
LCD_Data = " " : gosub LCD_Write    ;Line 1
LCD_Data = " " : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write 
LCD_Data = " " : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write
LCD_Data = "S" : gosub LCD_Write 
LCD_Data = "t" : gosub LCD_Write
LCD_Data = "e" : gosub LCD_Write
LCD_Data = "v" : gosub LCD_Write
LCD_Data = "e" : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write 
LCD_Data = "E" : gosub LCD_Write
LCD_Data = "a" : gosub LCD_Write
LCD_Data = "r" : gosub LCD_Write
LCD_Data = "l" : gosub LCD_Write

lcd_rs = 0                          ;Command is next
lcd_data=$a8 : gosub lcd_write      ;Move to start of line 2
pause 2
lcd_rs = 1                          ;Switch back to Data

LCD_Data = " " : gosub LCD_Write    ;Line 2
LCD_Data = " " : gosub LCD_Write
LCD_Data = "D" : gosub LCD_Write 
LCD_Data = "a" : gosub LCD_Write
LCD_Data = "t" : gosub LCD_Write
LCD_Data = "a" : gosub LCD_Write
LCD_Data = "g" : gosub LCD_Write
LCD_Data = "e" : gosub LCD_Write
LCD_Data = "o" : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write
LCD_Data = "L" : gosub LCD_Write
LCD_Data = "i" : gosub LCD_Write
LCD_Data = "m" : gosub LCD_Write
LCD_Data = "i" : gosub LCD_Write
LCD_Data = "t" : gosub LCD_Write
LCD_Data = "e" : gosub LCD_Write
LCD_Data = "d" : gosub LCD_Write

lcd_rs = 0                          ;Command is next
lcd_data=$99 : gosub lcd_write      ;Move to line 3 col 6 
pause 2
lcd_rs = 1                          ;Switch back to Data

LCD_Data = "*" : gosub LCD_Write    ;Line 3
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write 
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write
LCD_Data = "*" : gosub LCD_Write


lcd_rs = 0                          ;Command is next
lcd_data=$D8 : gosub lcd_write      ;Move to line 4 col 5
pause 2
lcd_rs = 1                          ;Switch back to Data

LCD_Data = "T" : gosub LCD_Write    ;Line 4
LCD_Data = "e" : gosub LCD_Write
LCD_Data = "s" : gosub LCD_Write
LCD_Data = "t" : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write
LCD_Data = "P" : gosub LCD_Write 
LCD_Data = "r" : gosub LCD_Write
LCD_Data = "o" : gosub LCD_Write
LCD_Data = "g" : gosub LCD_Write
LCD_Data = "r" : gosub LCD_Write
LCD_Data = "a" : gosub LCD_Write
LCD_Data = "m" : gosub LCD_Write

pause 5000
lcd_rs = 0                          ;Command is next
lcd_data=$D8 : gosub lcd_write      ;Move to line 4 col 5
pause 2
lcd_rs = 1                          ;Switch back to Data

LCD_Data = " " : gosub LCD_Write    ;Clear line 4 and set clock 
LCD_Data = " " : gosub LCD_Write
LCD_Data = "0" : gosub LCD_Write
LCD_Data = "0" : gosub LCD_Write
LCD_Data = ":" : gosub LCD_Write
LCD_Data = "0" : gosub LCD_Write
LCD_Data = "0" : gosub LCD_Write
LCD_Data = ":" : gosub LCD_Write 
LCD_Data = "0" : gosub LCD_Write
LCD_Data = "0" : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write
LCD_Data = " " : gosub LCD_Write

main:                               ;Count seconds and refresh the clock
for hours = 0 to 23
for minutes = 0 to 59
for seconds = 0 to 59  
lcd_rs = 0                          ;Command is next
lcd_data=$DA : gosub lcd_write      ;Move to line 4 col 7
pause 2
lcd_rs = 1                          ;Switch back to Data

LCD_Data = (hours dig 1)+48 : gosub LCD_Write 
LCD_Data = (hours dig 0)+48 : gosub LCD_Write
LCD_Data = ":" : gosub LCD_Write
LCD_Data = (minutes dig 1)+48 : gosub LCD_Write 
LCD_Data = (minutes dig 0)+48 : gosub LCD_Write
LCD_Data = ":" : gosub LCD_Write
LCD_Data = (seconds dig 1)+48 : gosub LCD_Write 
LCD_Data = (seconds dig 0)+48 : gosub LCD_Write
pause 1000
next    ;second
next    ;minute
next    ;hour
goto main


LCD_WRITE:
   LCD_E = 1
   IF LCD_WriteMode.1 = 1 THEN                             ; Write High Nibble
     LCD_Byte = (LCD_Byte & $0F) | (LCD_Data  & $F0)
     LCD_Byte2 = LCD_Byte & $FB    
     I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte, LCD_Byte2]
   ENDIF
  
   IF LCD_WriteMode.0 = 1 THEN                             ; Write Low Nibble
     LCD_Byte = (LCD_Byte & $0F) | ((LCD_Data << 4 )& $F0)
     LCD_Byte2 = LCD_Byte & $FB
     I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte, LCD_Byte2]
   ENDIF
return

[EarlyBird2]

Ambrogio,

Any feedback?

If you have no questions then I will post the next improvement which includes the command in the LCD_Write subroutine. I am now looking at using arrays as the next step.