122-28029 Parallax Inc, 122-28029 Datasheet - Page 184

• Manufacturer Part Number: 122-28029
• Description: GUIDE STUDENT SMART SENSORS
• Manufacturer: Parallax Inc

Specifications of 122-28029

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Smart Sensors
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Page 172 · Smart Sensors and Applications
For example, where the axes of the graph intersect at coordinates (0, 0) is actually
CRSRXY
program we would like to be able to type “-3-3” in to the Debug Terminal and have the
asterisk appear at graph coordinate (-3, -3), which would be
another example, when you type in 2,2,
10,1. Now, it’s time to figure out how to do this mapping translation using scale and
offset.
For values ranging from -3 to 3, the X value has to be multiplied by 2 and added to 6 for
CRSRXY
offset of 6. Here is a PBASIC statement to make the conversion from X coordinate to
number of spaces.
The Y value has to be multiplied by -1, then added to 3. That’s a scale of -1 and an offset
of 3. Here is a PBASIC statement to make the conversion from Y coordinate to number
of carriage returns.
Example Program – PlotXYGraph.bs2
' Smart Sensors and Applications – PlotXYGraph.bs2
' Position cursor on plot interactively in Debug Terminal
'{$STAMP BS2}
'{$PBASIC 2.5}
x
y
temp
√
√
√
√
position 6,3. (Compare this with Figure 5-2 until you see how this is so.) For this
to place the asterisk the right number of spaces over. That’s a scale of 2, and an
x = (x * 2) + 6
y = 3 - y
Try substituting X and Y coordinates in the right side of each of these equations,
do the math, and verify that each equation yields the right number of spaces and
carriage returns.
Enter and run PlotXYGraph.bs2.
Try entering the sequence of values: -3-3, -2-2, -1-1, 00, 11, 22, 33, and verify
that it matches the Debug Terminal example in Figure 5-3.
Try some other sequences and/or drawing shapes by their coordinates.
VAR
VAR
VAR
Word
Word
Byte
CRSRXY
actually needs to position the asterisk at
CRSRXY
position 0,6. As