Chameleon-PIC Nurve Networks, Chameleon-PIC Datasheet - Page 131

• Manufacturer Part Number: Chameleon-PIC
• Description: MCU, MPU & DSP Development Tools PIC24 & PROPELLER DEV SYSTEM (SBC)
• Manufacturer: Nurve Networks

Specifications of Chameleon-PIC

• Processor To Be Evaluated: PIC24
• Data Bus Width: 16 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

© 2009 NURVE NETWORKS LLC “Exploring the Chameleon PIC 16-Bit”
Figure 16.3 – Another view of the complete system dataflow model.
16.2.1 Complete Data Flow from User to Driver
Now that you have seen all the pieces of the puzzle from a hardware and software point of view, let’s review exactly how
these pieces all fit together. To begin with the Propeller is running a number of drivers on multiple cores; NTSC graphics
terminal, VGA graphics terminal, keyboard/mouse driver, and sound driver. Each one of these drivers takes a single core.
Now, by themselves, they don’t do much. So the “glue” of the system is the MCP which is pure SPIN program that not
only issues commands to the drivers, but is the interface to the PIC via the virtual SPI drivers’ shared memory.
Thus, the MCP runs on its own core controlling the media cores themselves as well as handing SPI input from the SPI
driver itself which is written in ASM running on its own core. With the system in this know state, let’s cover exactly what
happens in each phase when the system boots.
Initialization – After reset, the MCP software simply loads each of the drivers for NTSC, VGA, keyboard, and serial.
Finally, the main PUB start() of the MCP is entered and it starts a core with the assembly language SPI driver.
Command Processing Loop – As SPI commands are sent over the SPI channel, the virtual SPI driver listens and if it
detects traffic, it then processes the bytes and places them into a globally shared memory buffer. The MCP is sitting a
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