Chameleon-AVR Nurve Networks, Chameleon-AVR Datasheet - Page 188

• 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

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Function Prototype:
Description:
Example(s):
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Function Prototype:
Description:
Example(s):
per row).
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Function Prototype:
Description:
Example(s):
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unsigned int GFX_Read_Tilemap_Ptr(void);
unsigned int GFX_Write_Tilemap_Ptr(unsigned int tilemap_ptr);
unsigned int GFX_Read_Bitmap_Ptr(void);
Scroll down a line. Assumes 32x24 tile map (important thing is the row pitch, this defines how many bytes
Read the current bitmap pointer.
displayed. Each tile map entry is 2 bytes [palette index | character index], and the current tile map
width decides the pitch per row. The tile map pointer is of course relative to the Propeller’s 32K memory
space and an absolute address. Returns the 16-bit pointer value/address.
Read the tile map pointer.
displayed. Each tile map entry is 2 bytes [palette index | character index], and the current tile map
width decides the pitch. The pointer must be a valid address and within open memory or part of memory
declared for the driver itself, otherwise you could crash the Propeller, so watch out. Scrolling, page
flipping, and other memory effects can be achieved by changing the pointer. For example, say you want
to scroll the tilemap one row down? Assuming the current tilemap is 32x24 then we know there are 32
tiles per row and each tile is 2-bytes, thus 64 bytes per row. Therefore to scroll down a single row, we
simply need to add 64 to the current tile map pointer. The example that follows will show this. Returns 1.
Each bitmap is 8x8 pixels, 2-bits per pixel, 16-bytes each. The bitmap pointer is of course relative to the
Propeller’s 32K memory space and an absolute address. Returns the 16-bit pointer value/address.
GFX_Read_Tilemap_Ptr() reads the 16-bit tilemap pointer that points to the current tile map data
GFX_Write_Tilemap_Ptr(…) writes the 16-bit tilemap pointer that points to the current tile map data
GFX_Read_Bitmap_Ptr() reads the 16-bit bitmap pointer that points to the first bitmap indexed by tile 0.
© 2009 NURVE NETWORKS LLC “Exploring the Chameleon AVR 8-Bit”
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