OLED nexys video

[sosso]

hi everyone,

       Please i'm looking for informations about the nexys video OLED, how many characters can we write in the horiz and vert axes? can we modify the size of a character? can we use character when we speak about the oled writing area capability?

                           thank you so much

[JColvin]

Hi @sosso,

I apologize for the delay. My understanding is that there is not really an official term for these distances. Within the OLED controller, you can set the cursor to a single pixel anywhere on the display. When you use a pre-defined function to draw a character (as defined by the characters set in ChrFont0.c), the function sets each pixel to the appropriate state (on or off) within that 8x8 pixel area one at a time starting in the upper left hand corner before returning to the upper left hand corner of the next 8x8 pixel area directly to the right of the first. If there is not sufficient room to fit the full 8x8 character, the function will automatically wrap around back to the left hand side of the screen and (I believe) bring you 8 pixels lower down again so that you are not overwriting any previous material.

So, it is the same cursor that is moving the entire time on the screen. Internally to the OLED controller (a SSD1306), there is a column address pointer (vertical) and a page address pointer (horizontal) that is used by the controller to go to difference sections of the GDDRAM (graphic display data RAM), though you and I as the user do not have any control over these outside of configuring how they act and where the controller initially starts. There is some more information on this in the SSD1306 datasheet starting on page 25.

Thanks,
JColvin

[JColvin]

Hi @sosso,

The OLED on the Nexys Video has dimensions of 128 pixels horizontally and 32 pixels vertically. Each of the predefined characters take up a size of 8x8 pixels, leaving you with a total possible of 64 of the predefined characters to fit on the display.

In theory, it is possible to modify the size of the characters, there's a thread on our Forum about it here, though Digilent is not providing any official support for any custom character libraries. As a point of consideration, I wouldn't try to make any of the characters smaller since they will likely be too low of resolution to readily determine which letter is being shown.

Thanks,
JColvin

[sosso]

hi JColvin, 

       Thank you so much, how do we call the distance in which two lines of character are written?,

I mean there is the cursor which moves from the first to the second line,and there is a cursor which moves between pixels ( find it in the libraries controling the oled), I need the term for my dissertation, how can I express that ?

            thank you