Video Modes

The Uzebox currently supports 12 video modes (as of v3.3).

Mode 1

Mode 1 Example - Megatris

• The mode used in the original kernel (i.e: used for Megatris)
• 240x224 resolution
  • 6 or 8 pixels wide tiles
  • Configurable tile height
• Allows more than 256 unique tiles on screen by using 16 bit vram array (each entry is a direct memory pointer to a tile in flash)
• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: medium
• Program memory consumption: very low

See also

• Usage and implementation details

Mode 2

Mode 2 Example - Zombienator

• 144x224 resolution, 6x8 pixels tiles, 32x32 vram
• 8 bit vram array, each entry is an index into a 256 tiles table
• full screen scrolling
• multiples screen sections with independent scrolling, height, sprite priority and tile memory
• maximum 32 sprites at once, 6x8 pixels, up to 5 per scanline. No sprites flipping. (though now vertical flipping will be possible)
• Sprites blitting independent of background offset
• CPU cycles left: low
• RAM consumption: medium-high
• Program memory consumption: high due to unrolled loops (low if horizontal scrolling not required)

See Also

• Mode 2 Sprites Guide
• Mode 2 Screen Sections Guide

Mode 3

Mode 3 Example - Super Mario demo

Mode 3 Example - Donkey Kong

• Up to 240x224 resolution, 8x8 pixels tiles, up to 32x32 vram
• 8 bit vram array, each entry is an index into a 256 tiles table
• Full screen scrolling
• 1 scrolling main section and 1 static overlay section for scores, etc.
• Configurable number of sprites using 'ramtiles', sprites can be flipped on the X/Y axis and can be overlaid on other sprites. With the 4K RAM & CPU limit, about 20 sprites can be displayed at once. Aggregated sprites will allow a bigger total sprites count to to the tiles overlapping required when blitting sprites which position are not multiples of 8. (see note below about MAX_SPRITES)
• CPU cycles left: lowest
• RAM consumption: high
• Program memory consumption: medium

See also

• Usage and Implementation Details
• Ramtiles Effects Primer
• Sprites Techniques for Mode 3
• Hello World Tutorial for Mode 3

Mode 4

Mode 4 Example - Dungeon Slash Demo

Developed by David Etherthon

• 288x224 resolution, 16x16 pixels tiles
• full screen scrolling
• no sprites
• 8x8 text area section
• CPU cycles left: high
• RAM consumption: low
• Program memory consumption: medium

Mode 5

Mode 5 Example - Chess4uzebox

• Based on Mode 1, but using 8-bit indexes to save RAM
• 240x224 resolution, 6x8 pixels tiles, 40x28 vram
• 8 bit vram array, each entry is a index to a tile table (maximum 256 unique tiles on screen)
• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: low
• Program memory consumption: very low

Mode 6

Mode 6 Example - Vector Demo

Monochrome 1bpp ramtile-only video mode.

• Submodes: 240x224 (30x28 ramtiles) or 288x224 (36x28 ramtiles)
• Supports up to 256 ramtiles
• Foreground/Background colors can be changed per scanline in 240x224 submode
• Optimized point and lines functions
• CPU cycles left: low
• RAM consumption: medium
• Program memory consumption: medium

Mode 7

Mode 7 Example - Movie Player

Mode 7 is a video player. It plays uncompressed full screen movies at 30FPS with sound.

• 170x114 (147x114 effective) resolution, 30fps
• 256 colors per pixel
• Sound at 15.7Khz
• no scrolling
• no sprites
• CPU cycles left: low
• RAM consumption: low
• Program memory consumption: medium

Video Mode 7 Implementation Details

Mode 8

Mode 8 Example: Bitmap Demo

• 120x96 bitmapped mode
• 4 colors per pixel (2 bits per pixel)
• Global 4 color palette out of 256 colors
• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: medium
• Program memory consumption: very low

Mode 9

Mode 9 Example: Uze Snakes

Video mode 9 uses tiles that are actually compiled into AVR assembly ("code tiles"). It provides the highest resolution on the Uzebox. Sub mode "80" is useful for 80x25 text display.

• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: low
• Program memory consumption: very high (depending on tile count)
• Sub mode "60": 360x240, 60x28 tiles, 6x8 pixels tiles, 256 colors per pixel
• Sub mode "80": 480x240, 80x28 tiles, 6x8 pixels tiles, 2 colors per pixel

Video Mode 9 Implementation Details

Mode 90

These are two variants (Mode 90 and Mode 92) of Mode 9's Sub mode "60", offering much smaller code tiles (112 bytes / tile) along with other features.

• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: low
• Program memory consumption: high (depending on tile count)
• 16 color RAM palette with palette splits
• Mode 92: 2bpp double scanned 120 pixels wide graphics mode support on the top with arbitrary split

See the documentation within [videoMode90core.s] for details on usage. Tileset assembly files can be generated using the [program] provided along with the video mode. Video mode 92 is almost fully compatible with Video mode 90, except that it has a fixed tile height of 8 pixels.

Mode 10

Mode 10 Example: MegaSokoban

• Based on Mode 5, but using 12x16 pixel tiles to save RAM
• 192x192 resolution, 12x16 pixels tiles, 16x12 vram (with black border)
• 8 bit vram array, each entry is a index to a tile table (maximum 256 unique tiles on screen)
• no scrolling
• no sprites
• CPU cycles left: high
• RAM consumption: very low (around 3KB free)
• Program memory consumption: very low (depending on tile count - 192B per tile)

Mode 11

NOTE: This mode is a current work-in-progress.

Palette video mode 3 / Flash/RAM saver video mode 3 / Platformer video mode 3

• 240x224 resolution, flexible 16x4/8x8 pixel tiles, up to 32x32 vram
• Palette support for 16x4 tile lines, either 16 colors without or 136 colors with additional restrictions.
• 8 bit vram array, each entry is an index into a 256 tiles table
• Up to 4 different tilesets, one selectable for each 8x8/each two 16x4 pixel lines.
• full screen scrolling
• 1 scrolling main section and 1 static overlay section for scores, etc.
• configurable number of sprites using 'ramtiles', sprites can be flipped on the X axis and can be overlaid on other sprites. With the 4K RAM & CPU limit, about 20 sprites can be displayed at once. Aggregated sprites will allow a bigger total sprites count to to the tiles overlapping required when blitting sprites which position are not multiples of 16|4 or 8|8. (see note below about MAX_SPRITES)
• CPU cycles left: lowest
• RAM consumption: higher than video mode 3 with direct video sprites, slightly more than half of video mode 3 if sprites are in palette video, too.
• Program memory consumption: low

See also

• Video Mode 11 Implementation Details

Mode 12

Mode 12 Example: Uze8

"Chip 8" mode.

• Bitmappep mode: 1bpp
• Submode 0: 64x32
• Submode 1: 128x64

Mode 13 WIP

There is currently a work in progress for mode 13 paletted mode. It will be quite similar to video mode 3:

• 8x8 tiles for flash and ram tiles, 32 bytes each in size
• full screen scrolling
• screen overlay
• global palette of either 8 or 15 colours

Video Mode 13 Implementation Details

Mode 74

Mode 74 Example: Sprite engine demo

Paletted (4 bits per pixel) mode at 7 cycles per pixel (1,5:1 pixel aspect ratio, slightly wider pixels than in Video mode 3).

• Up to 192 pixels width (7 cycles per pixel; 24 tiles at 8 pixels per tile)
• X and Y scrolling
• Arbitrary (vertical) split screen regions
• 8x8 pixel tiles
• Normally 192 4 bits per pixel ROM tiles + (up to) 64 4 bits per pixel RAM tiles
• Each tile row's VRAM address and display mode is individually configurable
• Further row modes include 1 bit per pixel and 2 bit per pixel modes ("Multicolor")
• Sprite engine supports X and Y flipping, background priority (by masks) and recoloring
• The 16 color palette supports palette effects
• Loading random access data from SD card is possible during spare HSync time
• CPU cycles left: Depends on number of sprites used, may need lower vertical sizes for utilizing all RAM tiles
• RAM consumption: A 256 byte buffer is required for the palette, a RAM tile takes 32 bytes (half of Mode 3's respective consumption)
• Program memory consumption: Low to medium depending on required features (however ROM tiles for this mode are smaller than for Mode 3)

Mode 74 Quickstart, a short guide on how to start working with this video mode.

Additional Information

How Video Modes Work