122-32000 Parallax Inc, 122-32000 Datasheet - Page 329

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

WAITVID
Pause a cog’s execution until its Video Generator is available to take pixel data.
((PUB ┆ PRI))
Explanation
WAITVID
WAITPNE
pauses the cog until its Video Generator hardware is ready for the next pixel data, then the
Video Generator accepts that data and the cog continues execution with the next line of code.
When executed,
System Clock from causing further code execution within the cog until the moment the Video
Generator is ready. The wait hardware checks the Video Generator’s status every System
Clock cycle and the cog’s power consumption is reduced significantly during this time.
Using WAITVID
WAITVID
Since the Video Generator works independently from the cog itself, the two must synchronize
each time data is needed for the display device. The frequency at which this occurs depends
on the display device and the corresponding settings for the Video Generator, but in every
case, the cog must have new data available the moment the Video Generator is ready for it.
The cog uses the
the Video Generator.
The Colors parameter is a 32-bit value containing either four 8-bit color values (for 4-color
mode) or two 8-bit color values in the lower 16 bits (for 2-color mode). For VGA, each color
value’s upper 6-bits is the 2-bit red, 2-bit green, and 2-bit blue color components describing
the desired color; the lower 2-bits are “don’t care” bits. Each of the color values corresponds
to one of the four possible colors per 2-bit pixel (when Pixels is used as a 16x2 bit pixel
pattern) or as one of the two possible colors per 1-bit pixel (when Pixels is used at a 32x1 bit
pixel pattern).
WAITVID
•
•
, “Wait for Video Generator,” is one of four wait commands (
, and
Colors
possible colors of the pixel patterns in Pixels.
Pixels
is simply a delivery mechanism for data to the cog’s Video Generator hardware.
(Colors, Pixels )
is the next 16-pixel by 2-bit (or 32-pixel by 1-bit) pixel pattern to display.
WAITVID
is a long containing four byte-sized color values, each describing the four
WAITVID
WAITVID
) used to pause execution of a cog until a condition is met.
command to wait for the right time and then “hand off” this data to
activates special “wait” hardware in the cog that prevents the
4: Spin Language Reference –
Propeller Manual v1.0 · Page 329
WAITCNT
,
WAITPEQ
WAITVID
,