COURSES > DIGITAL LOGIC DESIGN (EEL3705.SP07.WEB_COHORT1) > COURSE LIBRARY > EXAMPLE CIRCUITS > VGA VIDEO DISPLAY EXAMPLES > TEXT DISPLAY AND KEYBOARD INPUT EXAMPLES > TEXT ONLY (NO KEYBOARD INPUT) |
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Display a 40x24 character page of text VGA_chars.zip (1.316 Mb) This example fills the display with a 40x24 array of text characters in white lettering on a black background. Currently, all characters are the same: They are all a "null" character glyph. However, this example could be used a starting point for designing a more full-featured character display. The FLEX 10K has enough internal storage to hold a (6 pixel wide)x(8 pixel tall)x(128 glyph) ROM font (6,144 bits) plus an (40 character wide)x(24 character tall)x(7 bits/character) text page RAM (6,720 bits). Together, these could be used to fill the VGA display with a modifiable 40x24 character array painted using a 320x240 array of "fat" 2x2 black-and-white pixels, with two fat pixels separating each row and column of text. |
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Display an ASCII table in a multi-color font VGA_font_color.zip (936.909 Kb) This logical extension of the previous example displays (several copies of) a full 16x8 character ASCII table, using the same glyphs and color codes for the control characters that I used when presenting ASCII in lecture. |
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Display a friendly welcome message VGA_char_ROM.zip (2.032 Mb) This example continues to build on the previous ones. Now, the text to be displayed is fetched from another ROM, instead of being automatically generated. This particular example displays a friendly welcome message on the VGA display. A useful next step would be to copy the message to a RAM character buffer upon initialization and then read it from there; this would allow the text to be dynamically modified. The design is starting to get pretty messy though, it needs to be cleaned up and better modularized. (Latest version.) This minor variation of the previous example adds a little logic to suppress the display of the glyph for the SP (space) character when the FLEX's pushbutton #1 (FLEX_PB1) is being held down. This is a little bit nicer looking and makes the text message a little bit more readable. |
