SSD1306 OLED (72x40) I2C display from scratch

**flotulopex** · - 16th November 2023, 05:51

Thanks a lot guys 👍

I'll give it a try this week-end.

And thanks Richard for condensing the information here

**flotulopex** · - 17th November 2023, 22:03

Only garbage at this time...but it's alive

Name: 72x40_first_life.png
Views: 13434
Size: 501.7 KB

**Ioannis** · - 18th November 2023, 13:24

Seems that the character size is too big to fit there..

Ioannis

**flotulopex** · - 19th November 2023, 08:04

...still struggeling with the ssd1306's datasheet to understand the "page" concept and how to display things.

This is the simplest and shortest code I'm working with for now, composed of different sources I found in this forum and also on ARDUINO's one:

Code:

' ====== DESCRIPTION ===============================================================================
' Use mini OLED 72x40 pixel display

' ====== FUSES =====================================================================================
' PIC 16F690 Fuses
' Internal oscillator  (activate OSCCON register)
@ __config _FCMEN_OFF &_IESO_OFF &_CPD_OFF &_WDT_OFF &_INTRC_OSC_NOCLKOUT &_BOR_OFF &_CP_OFF &_PWRTE_OFF &_MCLRE_OFF

@ ERRORLEVEL -306
@ ERRORLEVEL -202

' ====== REGISTERS =================================================================================
'             76543210
OPTION_REG = %10000000 'PORT A&B Pull-Ups disabled (see WPUA & WPUB)
OSCCON     = %01100000 'Internal RC set to 4MHZ
'ANSEL      = %00000000 'Select analog inputs Channels 0 to 7 (AN2 + AN4 selected)
'ANSELH     = %00000000 'Select analog inputs Channels 8 to 11
'ADCON0     = %10000000 'A/D Module (Bit5:2 select channels 0:11)
'ADCON1     = %00000000 'A/D control register
'CM1CON0    = %00000000 'Comparator1 Module is OFF
'CM2CON0    = %00000000 'Comparator2 Module is OFF
'INTCON     = %00000000 'INTerrupts CONtrol (TMR0 OFF)
'TRISA      = %00000000 'Set Input/Output (0 to 5)
'PORTA      = %00000000 'Ports High/Low (0 to 5)
'TRISB      = %00000000 'Set Input/Output (4 to 7)
'PORTB      = %00000000 'Ports High/Low (4 to 7)
'TRISC      = %00000000 'Set Input/Output (0 to 7)
'PORTC      = %00000000 'Ports High/Low (0 to 7)

' ====== DEFINES ===================================================================================
DEFINE OSC 4
'DEFINE NO_CLRWDT 1   'Don't waste cycles clearing WDT  
'DEFINE HSER_CLOERR 1 'Automatic clear overrun error 

' ====== VARIABLES =================================================================================
I2CDevice   var byte

SDA         VAR PORTB.4 ' I2C Data
SCL         VAR PORTB.6 ' I2C Clock

TEXT        VAR BYTE[20]
LENGTH      VAR BYTE[2]
DC          VAR Byte    ' "DATA OR COMMAND", $40=DATA; $0=COMMAND --> changed from bit to byte
LCD_DATA    VAR BYTE   
COM         VAR BYTE    ' COMMAND

I           VAR BYTE
J           VAR BYTE
X           VAR BYTE  'LCD POSITION X(0 TO 127)
Y           VAR BYTE  'LCD POSITION Y(0 TO 7)

' ====== INITIALIZE VARIABLES ======================================================================
I2CDevice = $78

'======= SSD1306 I2C OLED initialization ===========================================================
COM = $AE : GOSUB SEND_COMMAND ' turn off oled panel
COM = $D5 : GOSUB SEND_COMMAND ' set display clock divide ratio/oscillator frequency
COM = $80 : GOSUB SEND_COMMAND ' set divide ratio
COM = $A8 : GOSUB SEND_COMMAND ' set multiplex ratio
COM = $27 : GOSUB SEND_COMMAND ' 1/40 duty
COM = $D3 : GOSUB SEND_COMMAND ' set display offset
COM = $00 : GOSUB SEND_COMMAND ' not offset
COM = $AD : GOSUB SEND_COMMAND ' Internal IREF Setting	
COM = $30 : GOSUB SEND_COMMAND ' --
COM = $8D : GOSUB SEND_COMMAND ' set Charge Pump enable/disable
COM = $14 : GOSUB SEND_COMMAND ' set(0x10) disable
COM = $40 : GOSUB SEND_COMMAND ' set start line address
COM = $A6 : GOSUB SEND_COMMAND ' set normal display
COM = $A4 : GOSUB SEND_COMMAND ' Disable Entire Display On
COM = $A1 : GOSUB SEND_COMMAND ' set segment re-map 128 to 0
COM = $C8 : GOSUB SEND_COMMAND ' Set COM Output Scan Direction 64 to 0
COM = $DA : GOSUB SEND_COMMAND ' set com pins hardware configuration
COM = $12 : GOSUB SEND_COMMAND '
COM = $81 : GOSUB SEND_COMMAND ' set contrast control register
COM = $AF : GOSUB SEND_COMMAND ' 
COM = $D9 : GOSUB SEND_COMMAND ' set pre-charge period
COM = $22 : GOSUB SEND_COMMAND '
COM = $DB : GOSUB SEND_COMMAND ' set vcomh
COM = $20 : GOSUB SEND_COMMAND ' 
COM = $AF : GOSUB SEND_COMMAND ' turn on oled panel    

' ====== PROGRAM ===================================================================================
PAUSE 20
GOSUB CLEAR_LCD
GOSUB TITLE

MAIN:
    PAUSE 1000
    GOTO MAIN
END

' ====== CLEAR LCD =================================================================================
CLEAR_LCD:
    FOR J = 0 TO 7 
        FOR I = 0 TO 71 '127
            LCD_DATA = $00 : GOSUB SEND_DATA
        NEXT I
    NEXT J                             
    RETURN 
    
' ====== SEND COMMAND ==============================================================================
SEND_COMMAND:
    dc = $0
    I2CWrite SDA,SCL,I2CDevice,DC,[COM]
    dc = $40
    RETURN 
    
' ====== CLEAR LCD =================================================================================
SEND_DATA:
    DC = $40
    I2CWrite SDA,SCL,I2CDevice,DC,[LCD_DATA]
    RETURN
    
' ====== SEND DATA =================================================================================
FILL:
    FOR J = 0 TO 7
        FOR I = 0 TO 71 '127
            LCD_DATA = $FF : GOSUB SEND_DATA
        NEXT I
    NEXT J
    RETURN
    
' ====== TITLE =====================================================================================
TITLE:
    X = 0 : Y = 0 : GOSUB SET_XY
    FOR I = 0 TO 71 '127
        LOOKUP I,[$00,$40,$60,$50,$7E,$50,$60,$40,$02,$06,$0E,$1E,$3E,$00,$00,$00,_
        $00,$00,$00,$00,$00,$1F,$3F,$60,$60,$60,$60,$60,$60,$3C,$1C,$00,_
        $00,$7F,$7F,$61,$61,$61,$61,$61,$61,$3F,$1E,$00,$00,$1E,$3F,$61,_
        $61,$61,$61,$61,$61,$38,$18,$00,$00,$00,$00,$00,$00,$00,$00,$00,_
        $00,$00,$00,$00,$00,$00,$00,$1F,$3F,$60,$60,$60,$60,$60,$60,$3C,_
        $1C,$00,$00,$1E,$3F,$61,$61,$61,$61,$61,$61,$38,$18,$00,$00,$3F,_
        $7F,$60,$18,$06,$06,$18,$60,$7F,$3F,$00,$00,$00,$00,$00,$00,$00,_
        $00,$00,$00,$1C,$63,$41,$5D,$41,$5D,$41,$5D,$41,$5D,$41,$7F,$00],LCD_DATA
        lcd_data = lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I

    X = 0 : Y = 1 : GOSUB SET_XY
    for i = 0 to 71 '127
        lookup i,[$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,_
        $00,$00,$00,$00,$00,$F8,$FC,$06,$06,$06,$C6,$C6,$C6,$FC,$F8,$00,_
        $00,$FE,$FE,$80,$80,$80,$80,$80,$80,$00,$00,$00,$00,$18,$1C,$86,_
        $86,$86,$86,$86,$86,$FC,$78,$00,$00,$00,$00,$00,$00,$00,$00,$00,_
        $00,$00,$00,$00,$00,$00,$00,$F8,$FC,$06,$06,$06,$C6,$C6,$C6,$FC,_
        $F8,$00,$00,$18,$1C,$86,$86,$86,$86,$86,$86,$FC,$78,$00,$00,$FE,_
        $FE,$00,$00,$00,$00,$00,$00,$FE,$FE,$00,$00,$00,$00,$00,$00,$00,_
        $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00],lcd_data
        lcd_data=lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I

    X = 0 : Y = 3 : GOSUB SET_XY
    for i = 0 to 71 '127
        lookup i,[$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$3C,$7E,$C3,$C3,$C3,$C3,_
        $C3,$C3,$71,$30,$00,$00,$7F,$FF,$C3,$C3,$C3,$C3,$C3,$C3,$C3,$C3,_
        $00,$00,$7F,$FF,$C1,$C1,$C1,$C1,$C1,$C1,$FF,$7F,$00,$00,$7F,$FF,_
        $C3,$C3,$C3,$C3,$C3,$C3,$7E,$3C,$00,$00,$3F,$7F,$C0,$C0,$C0,$C0,_
        $C0,$C0,$70,$30,$00,$00,$FF,$FF,$03,$03,$03,$03,$03,$03,$FF,$FF,_
        $00,$00,$C0,$C0,$C0,$C0,$FF,$FF,$C0,$C0,$C0,$C0,$00,$00,$FF,$FF,_
        $0C,$0C,$03,$03,$00,$00,$FF,$FF,$00,$00,$3F,$7F,$C0,$C0,$C0,$C1,_
        $C1,$C1,$79,$39,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00],lcd_data
        lcd_data=lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I

    X = 0 : Y = 4 : GOSUB SET_XY
    for i = 0 to 71 '127
        lookup i,[$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$30,$38,$0C,$0C,$0C,$0C,_
        $0C,$0C,$F8,$F0,$00,$00,$F8,$FC,$0C,$0C,$0C,$0C,$0C,$0C,$0C,$0C,_
        $00,$00,$FC,$FC,$80,$80,$80,$80,$80,$80,$FC,$FC,$00,$00,$FC,$FC,_
        $80,$C0,$60,$30,$18,$0C,$04,$00,$00,$00,$F0,$F8,$0C,$0C,$0C,$0C,_
        $0C,$0C,$38,$30,$00,$00,$FC,$FC,$00,$00,$00,$00,$00,$00,$FC,$FC,_
        $00,$00,$0C,$0C,$0C,$0C,$FC,$FC,$0C,$0C,$0C,$0C,$00,$00,$FC,$FC,_
        $00,$00,$00,$00,$C0,$C0,$FC,$FC,$00,$00,$F0,$F8,$0C,$0C,$0C,$8C,_
        $8C,$8C,$F8,$F0,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00],lcd_data
        lcd_data=lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I

    X = 0 : Y = 5 : GOSUB SET_XY
    for i = 0 to 71 '127
        lookup i,[$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$1F,$3F,$30,$30,$30,$30,_
        $30,$30,$30,$30,$00,$00,$0F,$1F,$30,$30,$30,$30,$30,$30,$1F,$0F,_
        $00,$00,$1F,$3F,$30,$30,$30,$30,$30,$30,$1F,$0F,$00,$00,$00,$00,_
        $00,$00,$00,$0F,$1F,$30,$30,$30,$30,$30,$30,$1C,$0C,$00,$00,$30,_
        $30,$30,$30,$3F,$3F,$30,$30,$30,$30,$00,$00,$0F,$1F,$30,$30,$30,_
        $30,$30,$30,$1E,$0E,$00,$00,$3F,$3F,$03,$03,$00,$00,$00,$00,$3F,_
        $3F,$00,$00,$1F,$3F,$30,$30,$30,$30,$30,$30,$3F,$1F,$00,$00,$3F,_
        $3F,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00],lcd_data
        lcd_data=lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I

    X = 0 : Y = 6 : GOSUB SET_XY
    for i = 0 to 71 '127
        lookup i,[$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$FF,$FF,$C0,$C0,$C0,$C0,_
        $C0,$C0,$00,$00,$00,$00,$FC,$FE,$03,$03,$03,$03,$03,$03,$FE,$FC,_
        $00,$00,$FF,$FF,$E0,$F0,$D8,$CC,$C6,$C3,$81,$00,$00,$00,$00,$00,_
        $00,$00,$00,$0C,$8E,$C3,$C3,$C3,$C3,$C3,$C3,$7E,$3C,$00,$00,$03,_
        $03,$03,$03,$FF,$FF,$03,$03,$03,$03,$00,$00,$FC,$FE,$03,$03,$03,_
        $63,$63,$63,$7E,$7C,$00,$00,$FF,$FF,$00,$00,$C0,$C0,$30,$30,$FF,_
        $FF,$00,$00,$FF,$FF,$60,$60,$60,$60,$60,$60,$FF,$FF,$00,$00,$FF,_
        $FF,$03,$03,$03,$03,$03,$03,$03,$03,$00,$00,$00,$00,$00,$00,$00],lcd_data
        lcd_data=lcd_data rev 8
        GOSUB SEND_DATA
    NEXT I
    RETURN
    
'======= SET_XY ====================================================================================
SET_XY:
    COM = $21 : GOSUB SEND_COMMAND
    COM = X   : GOSUB SEND_COMMAND
    COM = 71  : GOSUB SEND_COMMAND
    COM = $22 : GOSUB SEND_COMMAND
    COM = Y   : GOSUB SEND_COMMAND
    COM = 41  : GOSUB SEND_COMMAND
    RETURN

Seems that the character size is too big to fit there..

Originally, this code is made for a larger display so I need to adapt it.

**Ioannis** · - 19th November 2023, 12:46

Is it worth it the effort to spend much time on this LCD's?

It tried it and seems a lot of waste of time. Also too small for my age

Ioannis

**flotulopex** · - 19th November 2023, 16:58

Up to now, I couldn't find any pixel map for the 72x40 display so I'm relying on information for the 128x64 one.

This is the information I have found in the 72x40 datasheet:
Name: 72x40_segments-coms.png
Views: 13497
Size: 11.8 KB

Name: 72x40_segments-coms.png
Views: 13497
Size: 11.8 KB

Can anybody tell me how I should convert this in "pages" if I have to do so? I don't understand how data has to be displayed...

This is the example from the 128x64's datasheet (to be found in attachment):
Name: 128x64.png
Views: 13649
Size: 71.4 KB