Chameleon-AVR Nurve Networks, Chameleon-AVR Datasheet - Page 166

• 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

© 2009 NURVE NETWORKS LLC “Exploring the Chameleon AVR 8-Bit”
The function that actually sends the command is listed below:
Even though you don’t directly call this function, its where all the action happens. Let’s go thru it line by line (I have added
manual line numbers in the listing to help). The function uses the built in SPI hardware and makes calls to the SPI
functions we already developed, so that makes things a lot easier. Here’s how it works:
Propeller Chip Selection
Step 1: Line 1 – here we select channel 2 with the SPI mux, this chip selects the Propeller chip as the target for SPI
traffic.
Data Transmission
Step 2: Lines 2,3 – here we simply send the 1st byte of the command packet and retrieve the 1st byte back in a buffer.
Step 3: Lines 4,5 – here we simply send the 2nd byte of the command packet and retrieve the 2nd byte back in a buffer.
rd
Step 4: Lines 6,7 – here we simply send the 3
byte of the command packet and retrieve the 3rd byte back in a buffer.
Propeller Chip De-Selection
Step 5: Lines 8,9 – here we de-select channel 2 with the SPI mux and select channel 0 (the NULL channel).
Results
Step 6: Line 10 – We return the 8-16 bit result to caller.
This is how all commands are sent to the Propeller chip.
Example(s):
Send command to NTSC driver to clear the screen. So first thing we do is look in the header file at the
command list in CHAM_AVR_TWI_SPI_DRV_V010.h (also the Propeller driver CHAM_DEFAULT2_DRV_112.SPIN has
the same list) and look up the command we want; GFX_CMD_NTSC_CLS, and now send the command with a function
call.
_______________________________________________________________________________________________
Function Prototype:
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