I2C lcd ( arduino ) with PICBASIC, help

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- 9th July 2014, 15:04
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Hi Steve,
I am back again on this LCD ...
I have repaired the programmer and so I had the occasion to test the program.
> Back light does not come on at all .
> nothing is displayed on the LCD
If you have something more to suggest, I am ready to go on .
Thanks
Regards,
Ambrogio
- 10th July 2014, 06:47
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

Hi Steve,
I am back again on this LCD ...
I have repaired the programmer and so I had the occasion to test the program.
> Back light does not come on at all .
> nothing is displayed on the LCD
If you have something more to suggest, I am ready to go on .
Thanks
Regards,
Ambrogio

Not good news then!

I need to refresh my memory. Post the full code you are using please.
- 10th July 2014, 08:09
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

here it is:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL
DEFINE I2C_SLOW 1
SDA VAR PORTD.2 ; I2C Data pin
SCL VAR PORTD.3 ; I2C Clock Pin
LCD_Addr CON 78
'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 0=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
testmode var byte

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

LCD_WriteMode = 1 ;-- Low Nibbles only
LCD_Data = 3 ; 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 2
LCD_Data = $06
gosub LCD_Write_ ; Entry Mode

PAUSE 2 ; Let command finish
LCD_RS = 1 ' this is data
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

Main:
LCD_Data = "T"
gosub LCD_Write_
LCD_Data = "e"
gosub LCD_Write_
LCD_Data = "s"
gosub LCD_Write_
LCD_Data = "t"
gosub LCD_Write_
goto main
- 10th July 2014, 08:43
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Please use code tags as it is easier for me to read.
- 10th July 2014, 09:02
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

here it is:

Code:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL DEFINE I2C_SLOW 1 SDA VAR PORTD.2 ; I2C Data pin SCL VAR PORTD.3 ; I2C Clock Pin LCD_Addr CON 78 '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 0=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 testmode var byte ;----[Initialize the LCD]------------------------------------------------------- PAUSE 250 ; LCD Power-on delay LCD_Backlight = 1 ; Backlight OFF LCD_RW = 0 ; Write to LCD LCD_RS = 0 ; Command Register LCD_WriteMode = 1 ;-- Low Nibbles only LCD_Data = 3 ; 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 2 LCD_Data = $06 gosub LCD_Write_ ; Entry Mode PAUSE 2 ; Let command finish LCD_RS = 1 ' this is data 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 Main: LCD_Data = "T" gosub LCD_Write_ LCD_Data = "e" gosub LCD_Write_ LCD_Data = "s" gosub LCD_Write_ LCD_Data = "t" gosub LCD_Write_ goto main

Need to add pauseus!

Code:

Main: LCD_Data = "T" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write_: PAUSEUS 50 goto main
- 10th July 2014, 10:40
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

And to test backlight is working try

Code:

Main: LCD_Backlight = 0 LCD_Data = "T" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write_: PAUSEUS 50 pause 500 LCD_Backlight = 1 LCD_Data = "-" gosub LCD_Write_: PAUSEUS 50 pause 500 goto main
- 10th July 2014, 17:02
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Steve,
I uploaded the two codes you have sent to me and checked them one at the time :
> backlight is still not working
> lcd show nothing
Thanks
Ambrogio
- 10th July 2014, 22:03
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Is the address correct? It is 78 in the code.

Try your code from post #24 as this did control the backlight.
- 11th July 2014, 07:55
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Steve,
this code still works well:
Thanks ,Ambrogio

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
- 11th July 2014, 08:49
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

Steve,
this code still works well:
Thanks ,Ambrogio

Code:

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

This works because you can see the backlight turn on and off. This tells me the LCD is working and the address is correct. Unfortunately that has eliminated the obvious. I will dig deeper into Darrel's code as I can not see anything that would stop it working.
- 12th July 2014, 09:50
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by EarlyBird2

This works because you can see the backlight turn on and off. This tells me the LCD is working and the address is correct. Unfortunately that has eliminated the obvious. I will dig deeper into Darrel's code as I can not see anything that would stop it working.

I have studied the HD44780 and PCF8574 datasheets and compared them to Darell's code and found as expected that his code follows the datasheets precisely. I compared the code

Code:

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

with Darrel's and noticed the I2C_SLOW definition is not included in his code. I then looked at I2CWRITE in the manual and noticed that PAUSE 10 is used to allow time for the transfer to complete again this is not included in Darrel's code.

What does this indicate is the question?

I compared PBP2.5 and pbp3 manuals and the I2CWRITE instruction is the same. I wondered if the pause in PBP3 is not needed as the compiler takes care of the I2C being busy.

One step at a time.
First remove the I2C_SLOW and test

Code:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL 'DEFINE I2C_SLOW 1 SDA VAR PORTD.2 ; I2C Data pin SCL VAR PORTD.3 ; I2C Clock Pin LCD_Addr CON 78 '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 0=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 testmode var byte ;----[Initialize the LCD]------------------------------------------------------- PAUSE 250 ; LCD Power-on delay LCD_Backlight = 1 ; Backlight OFF LCD_RW = 0 ; Write to LCD LCD_RS = 0 ; Command Register LCD_WriteMode = 1 ;-- Low Nibbles only LCD_Data = 3 ; 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 2 LCD_Data = $06 gosub LCD_Write_ ; Entry Mode PAUSE 2 ; Let command finish LCD_RS = 1 ' this is data 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 Main: LCD_Backlight = 0 LCD_Data = "T" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write_: PAUSEUS 50 pause 500 LCD_Backlight = 1 LCD_Data = "-" gosub LCD_Write_: PAUSEUS 50 pause 500 goto main

Then add pause 10 delays

Code:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL 'DEFINE I2C_SLOW 1 SDA VAR PORTD.2 ; I2C Data pin SCL VAR PORTD.3 ; I2C Clock Pin LCD_Addr CON 78 '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 0=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 testmode var byte ;----[Initialize the LCD]------------------------------------------------------- PAUSE 250 ; LCD Power-on delay LCD_Backlight = 1 ; Backlight OFF LCD_RW = 0 ; Write to LCD LCD_RS = 0 ; Command Register LCD_WriteMode = 1 ;-- Low Nibbles only LCD_Data = 3 ; 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 2 LCD_Data = $06 gosub LCD_Write_ ; Entry Mode PAUSE 2 ; Let command finish LCD_RS = 1 ' this is data 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] PAUSE 10 I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte2] PAUSE 10 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] PAUSE 10 I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte2] PAUSE 10 ENDIF return Main: LCD_Backlight = 0 LCD_Data = "T" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write_: PAUSEUS 50 pause 500 LCD_Backlight = 1 LCD_Data = "-" gosub LCD_Write_: PAUSEUS 50 pause 500 goto main

and let me know the outcome.

I will continue looking for answers.
- 12th July 2014, 20:58
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Hi Steve,
no change using both codes.
I still have no backlight and no text.
I appreciate your assistance on this matter: thanks a lot.
I am not skilled enough to go deeper in those kind of codes ...
Regards,
Ambrogio
- 12th July 2014, 21:33
pedja089

Re: I2C lcd ( arduino ) with PICBASIC, help

Can I make one suggestion?
First connect few led on output of PCF8574, and control them. So you are sure that I2C communication woks.
Second connect LCD to PIC directly, get timing and control right.
Then just combine that two.
- 12th July 2014, 22:18
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Try again

Code:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL DEFINE I2C_SLOW 1 SDA VAR PORTD.2 ; I2C Data pin SCL VAR PORTD.3 ; I2C Clock Pin LCD_Addr CON 78 '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 0=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 testmode var byte ;----[Initialize the LCD]------------------------------------------------------- PAUSE 1000 ; LCD Power-on delay LCD_Backlight = 1 ; Backlight OFF LCD_RW = 0 ; Write to LCD LCD_RS = 0 ; Command Register LCD_WriteMode = 1 ;-- Low Nibbles only LCD_Data = 3 ; 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 2 LCD_Data = $06 gosub LCD_Write ; Entry Mode PAUSE 2 ; Let command finish LCD_RS = 1 ' this is data 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 Main: I2CWRITE SDA,SCL, LCD_Addr, [%00000000] ' bck_lt= off PAUSE 200 I2CWRITE SDA,SCL, LCD_Addr, [%00001000] ' bck_lt=on PAUSE 200 LCD_Data = "T" gosub LCD_Write: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write: PAUSEUS 50 LCD_Data = "-" gosub LCD_Write: PAUSEUS 50 pause 500 goto Main
- 13th July 2014, 10:13
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

The problem could be with the delay on power up not being long enough for the LCD to initialise before the PIC starts.

Adjust this line and test

;----[Initialize the LCD]-------------------------------------------------------
PAUSE 1000 ; LCD Power-on delay

and please let me know the result.
- 13th July 2014, 18:11
iw2fvo

1 Attachment(s)

Re: I2C lcd ( arduino ) with PICBASIC, help

Dear Steve:

Your suggested test gave me the response on the lack of operation. ( see the attached).
The pcf has P0, P5 and P6 not working. This is the reason of the trouble.
I will no longer buy components on Ebay expecially if chinese. That is very bad.
I have no words to express my state. I want to apologize .
Thanks for the help given to me since the beginning.
Will try to buy another expander board: do you know some reliable seller in Europe ?
Regards,
Ambrogio
- 14th July 2014, 06:03
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

Dear Steve:

Your suggested test gave me the response on the lack of operation. ( see the attached).
The pcf has P0, P5 and P6 not working. This is the reason of the trouble.
I will no longer buy components on Ebay expecially if chinese. That is very bad.
I have no words to express my state. I want to apologize .
Thanks for the help given to me since the beginning.
Will try to buy another expander board: do you know some reliable seller in Europe ?
Regards,
Ambrogio

No problem and no need to apologise. Could you do some more testing on this board?
Check the voltages on the P0 to P7 pins when this program is running.

Code:

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] ' port off PAUSE 200 I2CWRITE D, C, ADDR, [%11111111] ' port on PAUSE 200 GOTO MAIN

If all pins change then the PCF8574 chip is good indicating that the fault is either bad soldering or bad PCB track. It is possible to solder jumper wire direct to pins for a temporary repair.
- 14th July 2014, 08:54
richard

Re: I2C lcd ( arduino ) with PICBASIC, help

are you sure the new board has 8574t on it not a 8574A ?
that might make a world of difference
- 14th July 2014, 09:04
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

=richard;127791]are you sure the new board has 8574t on it not a 8574A ?
that might make a world of difference

It is definitely a 8574T as shown in #36 and copied below.

http://www.picbasic.co.uk/forum/atta...1&d=1404048736[
- 14th July 2014, 10:19
richard

2 Attachment(s)

Re: I2C lcd ( arduino ) with PICBASIC, help

is that the current device or the one that got zapped ?
I found a 8574a in my junk box and fed your code into it (no lcd) and it seems ok (address is $78 for a version)
the attached pcf8574a.txt file is really a salea logic data/setting file and should be renamed to pcf8574a.logicdata , if you don't have a salea logic analyser you can download the software from salea logic and view the complete data
- 14th July 2014, 10:25
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Steve,
I did run the program:
P0, P5 and P6 do not toggle: they are always at 0vdc as seen by the scope.
I did check the tracks : there is good continuity between each pin of the PCF and the display pins.
I assume the pcf is gone or the module has been sent with a broken pcf.
As you have seen in the photos, I have changed the contrast pot because it was shorting the 5 vdc to ground , I fit a new one with a "crossed" pins.
Will order a new board from a reliable seller ... I am searching for it here.
Thanks for all.
Ambrogio
- 14th July 2014, 10:43
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by richard

is that the current device or the one that got zapped ?
I found a 8574a in my junk box and fed your code into it (no lcd) and it seems ok (address is $78 for a version)
the attached pcf8574a.txt file is really a salea logic data/setting file and should be renamed to pcf8574a.logicdata , if you don't have a salea logic analyser you can download the software from salea logic and view the complete data

It is the current device.

The PCF8574 and PCF8574A are identical, except for the different fixed portion of the slave address. The address used is 78 which fits with it being a PCF8574T and you use $78 which again fits with yours being a PCF8574AT.
- 14th July 2014, 10:46
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Thanks Richard,
I confirm that the address is OK since I can get some pins toggling correctly.
the PCF has definitively some "broken" port pins.
I still have the suspect that this is a fake board: It has the contrast pot error ... and now it has this issue !
Thanks a lot
Ambrogio
iw2fvo
- 14th July 2014, 10:50
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

Steve,
I did run the program:
P0, P5 and P6 do not toggle: they are always at 0vdc as seen by the scope.
I did check the tracks : there is good continuity between each pin of the PCF and the display pins.
I assume the pcf is gone or the module has been sent with a broken pcf.
As you have seen in the photos, I have changed the contrast pot because it was shorting the 5 vdc to ground , I fit a new one with a "crossed" pins.
Will order a new board from a reliable seller ... I am searching for it here.
Thanks for all.
Ambrogio

Well done it is the PCF!
I am surprised I thought the PCF was the least likely cause the PCB track or soldering fault was the most likely cause.
- 14th July 2014, 11:10
richard

Re: I2C lcd ( arduino ) with PICBASIC, help

this looks cheap
http://www.dx.com/p/raspberry-pi-pcf...Q#.U8OsSWflp_Q
- 16th July 2014, 08:32
EarlyBird2

1 Attachment(s)

Re: I2C lcd ( arduino ) with PICBASIC, help

I have bought this

Attachment 7392

from

http://4tronix.co.uk/store/index.php...product_id=158
- 17th July 2014, 07:46
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

I have tested this code and it works!

Code:

DEFINE OSC 40 ' 10 MHz XTAL AND X 4 INTERNAL PLL 'DEFINE I2C_SLOW 1 SDA VAR PORTD.2 ; I2C Data pin SCL VAR PORTD.3 ; I2C Clock Pin LCD_Addr CON 78 '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 0=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 testmode var byte ;----[Initialize the LCD]------------------------------------------------------- PAUSE 250 ; LCD Power-on delay LCD_Backlight = 1 ; Backlight OFF LCD_RW = 0 ; Write to LCD LCD_RS = 0 ; Command Register LCD_WriteMode = 1 ;-- Low Nibbles only LCD_Data = 3 ; 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 2 LCD_Data = $06 gosub LCD_Write_ ; Entry Mode PAUSE 2 ; Let command finish LCD_RS = 1 ' this is data 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 Main: LCD_Backlight = 0 LCD_Data = "T" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "e" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "s" gosub LCD_Write_: PAUSEUS 50 LCD_Data = "t" gosub LCD_Write_: PAUSEUS 50 pause 500 LCD_Backlight = 1 LCD_Data = "-" gosub LCD_Write_: PAUSEUS 50 pause 500 goto main
- 17th July 2014, 08:15
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

I am not a good programmer and I would like to convert the PBP program that is normally used now to EASY control the I2C display.
At the moment I am using this piece of code:

INS CON 254 ' $FE: INSTRUCTION COMMAND MODE
CLR CON 1 ' CLEAR LCD , GOTO FIRST LINE, FIRST CHARACTER
DG CON 223 ' DEG SYMBOL °
LINE1 CON 128 ' $80: GOTO LINE 1
LINE2 CON 192 ' $C0: GOTO LINE 2
LINE3 CON 148 ' $94: GOTO LINE 3
LINE4 CON 212 ' $D4: GOTO LINE 4

And then I do the the following to write my own data on it:

LCDOUT INS, LINE2, " V=", DEC2 VLT/10, ".", DEC1 VLT

How could I translate the above in I2C enviroment for displaying ?

Thanks for the assistance
Regards,
Ambrogio
IW2FVO

How to do this as neatly as possible are the next steps.
- 17th July 2014, 08:42
richard

Re: I2C lcd ( arduino ) with PICBASIC, help

the ext modifier should help
lcdb VAR BYTE[22]

ASM
lcd_cmd = _lcdb
lcd_buff = _lcdb+2

ENDASM
these must be after the asm code

lcd_cmd var byte EXT
lcd_buff var byte EXT

lcdb[0]=$fe
lcdb[1]= your lcd command eg 1 $80 $c0

use arraywrite to load lcd_buff (max 20 chrs)

then you can pass
lcd_cmd to your lcd write code if you need to send a cmd with your lcd string
or pass lcd_buff if no cmd required

ps don't forget to add a dely after a cmd to give the lcd time to act

ps ps
the asm names are case sensitive

left a bit out

lcd_cmd var byte EXT
lcd_buff var byte EXT

not sure if it needs to be try it and see

lcd_cmd var byte[2] EXT
lcd_buff var byte[20] EXT
- 17th July 2014, 08:54
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by richard

the ext modifier should help
lcdb VAR BYTE[22]

ASM
lcd_cmd = _lcdb
lcd_buff = _lcdb+2

ENDASM

lcdb[0]=$fe
lcdb[1]= your lcd command eg 1 $80 $c0

use arraywrite to load lcd_buff (max 20 chrs)

then you can pass
lcd_cmd to your lcd write code if you need to send a cmd with your lcd string
or pass lcd_buff if no cmd required

ps don't forget to add a dely after a cmd to give the lcd time to act

ps ps
the asm names are case sensitive

left a bit out

lcd_cmd var byte EXT
lcd_buff var byte EXT

not sure if it needs to be try it and see

lcd_cmd var byte[2] EXT
lcd_buff var byte[20] EXT

Quote:

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

Ambrogio is using pbp2.5 and I am even older on 2.46.
- 17th July 2014, 08:57
richard

Re: I2C lcd ( arduino ) with PICBASIC, help

without arraywrite that's a lot of code
- 17th July 2014, 08:58
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by richard

without arraywrite that's a lot of code

and a lot more fun!

I am only along for the ride and to keep my brain ticking over. :smile:
- 17th July 2014, 09:11
richard

Re: I2C lcd ( arduino ) with PICBASIC, help

does 2.5 have the dig command
- 17th July 2014, 12:09
Dave

Re: I2C lcd ( arduino ) with PICBASIC, help

The DIG modifier has been there forever....
- 17th July 2014, 17:05
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Steve,
it is a very good new !
I am looking to place an order for a couple of new extender boards. The point is the lead time .
I will let you know.
I appreciate your assistance.
Regards,
Ambrogio
- 17th July 2014, 17:13
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

Thanks to all of you for the assistance.
What is the dig modifier please ?
Thnaks
Ambrogio
- 17th July 2014, 18:20
pedja089

Re: I2C lcd ( arduino ) with PICBASIC, help

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)
- 18th July 2014, 08:43
EarlyBird2

Re: I2C lcd ( arduino ) with PICBASIC, help

Quote:

Originally Posted by iw2fvo

Steve,
it is a very good new !
I am looking to place an order for a couple of new extender boards. The point is the lead time .
I will let you know.
I appreciate your assistance.
Regards,
Ambrogio

No next day delivery in Italy?

I ordered my LCD and backpack for £9.30 including next day delivery, details in #66.

The test program is not very useful as it only tests the LCD is working. I will add commands so that the screen can be cleared and the cursor can be positioned anywhere on the screen.
- 18th July 2014, 08:57
iw2fvo

Re: I2C lcd ( arduino ) with PICBASIC, help

That is clear to me now.
Thanks
Ambrogio
- 19th July 2014, 10:29
EarlyBird2

1 Attachment(s)

Re: I2C lcd ( arduino ) with PICBASIC, help

Ambrogio

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

Attachment 7394

Let me know when you are ready.

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