Chameleon-AVR Nurve Networks, Chameleon-AVR Datasheet - Page 25

• 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

BOEn
RESn
XI
XO
The Parallax Propeller is really useful for doing many things at once without trying to use interrupts, multitasking, and
round robin programming techniques to perform multiple tasks. You simply write your code and run it on a core. Then if
that code crashes or is broken it does not affect the other cores at all! This is exactly what the Chameleon needs – a way
to run multiple processes that each perform some kind of media task and then these processes wait for the master (the
AVR) to send commands. Each core does not care what the neighboring cores are doing, only what it is doing.
Luckily, if this all sounds like this is way too complicated, you don’t’ have to worry about it! You do not have to program the
Propeller chip at all if you do not want to. The AVR communicates to it via a simple API, and from the AVR (your)
perspective, the Propeller is just a media slave that generates NTSC/PAL/VGA graphics, plays sounds, reads mice and
keyboards and more. However, to really explore the power of the Chameleon you will definitely want to play with the
Propeller chip and modify its kernel driver(s) and so forth. This is actually quite easy to do with a single tool that interfaces
to the Chameleon AVR over the USB port. Its called the Propeller IDE, and Figure 1.10 below shows a screen shot of it.
The Propeller IDE allows you to program the Propeller chip in its native BASIC like language called “Spin” as well as
assembly language. The editor has lots of features like syntax highlighting and code marking to help you keep things
straight. Spin uses tabs for block nesting, so a little tricky if you’re a BASIC or C/C++ programmer and not used to
spaces/tabs indicating nesting. In any event, if you want to program the Propeller you will use Spin/ASM primarily.
However, there are 3
I
I/O
I
O
rd
party C compilers, a FORTH is available, and other languages if you search the Parallax site.
Brown Out Enable (active low). Must be connected to either VDD or VSS. If low, RESn becomes a weak output
(delivering VDD through 5 k ) for monitoring purposes but can still be driven low to cause reset. If high, RESn is
CMOS input with Schmitt Trigger.
Reset (active low). When low, resets the Propeller chip: all cogs disabled and I/O pins floating. Propeller restarts 50
ms after RESn transitions from low to high.
Crystal Input. Can be connected to output of crystal/oscillator pack (with XO left disconnected), or to one leg of crystal
(with XO connected to other leg of crystal or resonator) depending on CLK Register settings. No external resistors or
capacitors are required.
Crystal Output. Provides feedback for an external crystal, or may be left disconnected depending on CLK Register
settings. No external resistors or capacitors are required.
Figure 1.10 – The Propeller IDE in action.
© 2009 NURVE NETWORKS LLC “Exploring the Chameleon AVR 8-Bit”
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