Chameleon-AVR Nurve Networks, Chameleon-AVR Datasheet - Page 37

• Manufacturer Part Number: Chameleon-AVR
• Description: MCU, MPU & DSP Development Tools AVR8 & PROPELLER DEV SYSTEM (SBC)
• Manufacturer: Nurve Networks

Specifications of Chameleon-AVR

• Processor To Be Evaluated: AVR 328P
• Data Bus Width: 8 bit
• Interface Type: USB, VGA, PS/2, I2C, ISP, SPI
• Operating Supply Voltage: 3.3 V, 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.1 Origins of the VGA
Before we start into the design, let’s get some history and terminology correct. First, the last time I saw a real VGA
monitor was about 20 years ago, the new 21
typically multisync, variable refresh, and can go up to 2400x2400 or more. The “VGA” specification is more of a base point
than anything anyone actually uses anymore. IBM released the VGA or “Video Graphics Array” technology in 1987
roughly. It was touted to change the world (definitely an improvement from CGA and EGA), but it was doomed from the
start with not enough resolution, shortly after, higher resolution monitors were available and the VGA specification was
enhanced with the Super VGA standard, but this was only a momentary hold on its execution, what was needed was a
more progressive standard that could change at any time, and thus the VESA “Video Electronics Standard
Association” graphics cards and drivers were created and the rest is history. However, the original specs for the VGA
are shown below.
Standard graphics modes supported by VGA are:
I spent many years writing graphics algorithms and drivers for VGA cards to push them to the outer limit; now, my cell
phone has better graphics! However, the VGA spec is great for baseline computer displays and any standard modern
computer monitor will display old school 640x480 VGA modes and refresh rates. However, the Propeller chip can
generate VGA modes at much higher resolutions and there are a number of multicore hi-resolution drivers that you can
employ that go all the way up to 1200x1024 or greater last time I checked on the Parallax Object Exchange. You can
use any of these drivers with the Chameleon! You just need to modify the Propeller driver module, include the new VGA
drivers, make connections to it via commands, and you are off and running.
256 KB Video RAM.
16-color and 256-color modes.
262,144-value color palette (six bits each for red, green, and blue).
Selectable 25 MHz or 28 MHz master clock.
Maximum of 720 horizontal pixels.
Maximum of 480 lines.
Refresh rates up to 70 Hz.
Planar mode: up to 16 colors (4 bit planes).
Packed-pixel mode: 256 colors, 1-byte per pixel (Mode 13h).
Hardware smooth scrolling support.
Some "raster operations" (Raster Ops) support to perform bitmap composition algorithms.
Barrel shifter in hardware.
Split screen support.
Soft fonts.
Supports both bitmapped and alphanumeric text modes.
640×480 in 16 colors.
640×350 in 16 colors.
320×200 in 16 colors.
320×200 in 256 colors (Mode 13h, "chunky graphics mode").
st
century monitors that you are used to are super-sets of VGA, they are
© 2009 NURVE NETWORKS LLC “Exploring the Chameleon AVR 8-Bit”
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