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how to read contents from OLED

Radhika Anabathula
Intellectual 390 points

hi,

This is radhika. I'm using tiva cortex-M4 TM4C123G6PGE  microcontroller. I done programming for displaying contents on OLED, but i unable to read contents from OLED. please provide the code to read from particular location on OLED.

  • 0
    TI__Guru**** 244440 points

    Hello Radhika,

    Good that the content can be displayed on OLED, but how do the forum members know which OLED is it? With what interface are you interfacing the OLED?

    And what have you done to read the data from the OLED? We cannot simply provide for a code but help you construct  and debug if there is an issue.

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Intellectual 390 points

    I'm using 8-bit SSI interface. size of OLED is 96x64  

  • 0 in reply to Radhika Anabathula
    TI__Guru**** 244440 points

    Hello Radhika,

    Still the details eludes us, as without knowing what OLED panel it is is I would make an assumption that all transactions will be valid to the panel.

    Also I would assume that you do not have a SSI code for reading the OLED panel?

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Intellectual 390 points

    and after reading the data from OLED i want to strore it into EEPROM. In datasheet one method is there i.e GrStringGet() with 3 parameters.how to use this method and what parameters exactly i need to pass i'm confusing. can u please refer code which is in examples relateted to tiva TM4C123G6PGE controller. 

  • 0 in reply to Amit Ashara
    Intellectual 390 points

    It is dot matrix OLED.  CFAL9664B-F-B1 is part num please check it once. you can know full details.

  • 0 in reply to Radhika Anabathula
    Prodigy 170 points

    Hello,

    Please confirm if you are using the SPI mode or 8-bit data mode of interfacing.

    Also, are you using the Tiva Development board DK-TM4123G?

    The function you are referring GrStringGet() just returns the string from the string table. Please ensure you refer datasheets correctly.

    I assume you want to read the data that is displayed on OLED; is it?

  • 0 in reply to blueshift g5
    Intellectual 390 points

    I'm using SPI mode of interfacing on DK-TM4C123G6PGE.

    i want to read data that is displayed on OLED. 

    I refered datasheet of grlib i got information like before going to display on OLED it will be stored in string table so i'm trying to retrive from string table but little bit confusing.

    you can tell me how can i read data from OLED that is better option to me.

  • 0 in reply to Radhika Anabathula
    Guru 47900 points

    Such small, inexpensive displays do not "always" provide the ability to "read" the display's RAM. 

    An alternative method - which always works - is to "mirror" the display data w/in either MCU or external RAM.  In fact - this "dual buffered" memory scheme has merit with larger displays too - where screen updates can be expected to cause noticeable/objectionable, "screen artifacts."

    If most of your screen writes are simple text strings - it makes little sense to "read from the display."  (the display knows nothing of fonts nor strings)  Recovery of screen-resident text strings is far better done via the "mirrored, memory to screen" method described above.  (it's far easier - and faster - to read from an MCU buffer than from a screen, "pixel dump...")

    And - even if you could recover each/every pixel value from your screen - what then?  Seems much work - little return - n'est pas? 

    Clearly the better way to go is to write to some, "off screen RAM Buffer" and then transfer that buffer content to your screen.  Should your screen content be primarily text strings - a spectacular improvement in eased effort, bus traffic and time saving results.  Sometimes the "best answer" is not that which you sought...