Chameleon-PIC Nurve Networks, Chameleon-PIC Datasheet - Page 225

• 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

And any other ancillary drivers keyboard, mouse, etc.
All the required files can of course be found in the \Source directory on the DVD (which you should have already copied
onto your hard drive) located here:
30.1.1 Propeller Local Port LED Blinker Demo
The Propeller chip on the Chameleon had 8 free I/O pins, so we decided to add an 8-bit port to it. With this, you can
interface SD cards, SPI memory, control servos, whatever. Of course, the PIC itself has all its I/O headers. But, give the
Propeller a direct port itself allows drivers running on the Propeller to do more stuff. Anyway, that’s what the Propeller 8-bit
port is all about. And this simple demo shows how to set the I/O pin directions and blink and LED. All we need is the
Propeller Port API library and an LED to plug into the Propeller port – which we happen to supply with your Chameleon.
Now, you might have a red, green, blue, or bi-color LED. Doesn’t matter which, just plug it into the 2-left most pin headers
of the Propeller Port as shown in Figure 31.1 below.
Figure 31.1 – A screen shot of the NTSC output (left) and the actual LED blinking on the Chameleon (right).
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The System API library module CHAM_PIC_SYSTEM_V010.c|h.
The main SPI API library module CHAM_PIC_I2C_SPI_DRV_V010.c|h.
The serial API library module CHAM_PIC_UART_DRV_V010.c|h.
The FLASH API library module CHAM_PIC_FLASH_DRV_V010.c|h.
The Propeller local 8-bit port API library module CHAM_PIC_PROP_PORT_DRV_V010.c|h.
The NTSC, VGA, GFX driver or all of them.
DVD-ROM:\ CHAM_PIC \ SOURCE \
MPLAB
TIP
TIP
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If you are into electronics, you might be concerned that we are plugging the LED directly
into two I/O ports and it might burn the LED out? This is a valid concern, but luckily, the
forward voltage of the LED is about 2.2 – 2.5V, so the 3.3V outputs of the Propeller are
just enough to turn it on and the LED will draw a limited amount of current. Moreover,
the Propeller I/O ports can actually source or sink 40ma, so you can even drive little
light bulbs. Your second concern might be there is no ground on the 8-bit port, so how
does this work? Well, when we set an I/O to digital 0, it’s at a virtual ground and being
pulled to GROUND by a transistor switch, so as long as the amount of current your draw
thru the circuit isn’t too much, the virtual ground will remain very close to 0. If you draw a
lot of current then the ground will “rise” or “float” up due to the voltage drop over the
transistor switch pulling the pin LOW.
In general, you will include all the sources in your project (.C files) and make sure all the
.H header files are in the same working directory, so the compiler can find them. You do
NOT include the .H header files in the compilation list of source files, the compiler will do
this for you. Only include .C and .S files in your source file link list in your project file list
to the left of the tool.
© 2009 NURVE NETWORKS LLC “Exploring the Chameleon PIC 16-Bit”
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