28029 Parallax Inc, 28029 Datasheet - Page 155

• Manufacturer Part Number: 28029
• Description: KIT PARTS SMART SENSORS W/TEXT
• Manufacturer: Parallax Inc

Specifications of 28029

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: BASIC Stamp® or Javelin Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 28029PAR

Your Turn - Displaying "Degrees" as °
Displaying the degree ° symbol in the Debug Terminal was first introduced in Chapter
#3, Activity #5.
ACTIVITY #4: IMPROVE COMPASS MEASUREMENTS BY AVERAGING
You may have noticed that the x and y measurements in the Debug Terminal tended to
alternate between two or even three different values. This is the result of several different
types of interference that are collectively called noise. Some common culprits are nearby
AC devices and power lines, digital activity in the BASIC Stamp, and even digital
activity inside the HM55B chip.
ELSE
ENDIF
' After the offset between the current angle measurement and the next lower
' table measurement has been determined, this code block uses it along with
' the span between the table entries above and below the angle measurement
' to solve for: angle(corrected) = angle(offset) * 16 / span.
' This code block also rounds up or down by comparing the remainder of
' the angleOffset / span division to the value of (span / 2).
angleOffset = angleOffset * 16
angle = (angleOffset / span) + ((angleOffset // span) / (span / 2))
angle = ((index - 1 & $F) * 16) + angle
angle = angle & $ff
RETURN
√
span = table(current) + (255 - table(previous))
angleOffset = angle + (255 - table(previous))
index = index - 1
READ CompassCal + index, table(current)
DO
LOOP
table(previous) = table(current)
index = index + 1
READ CompassCal + index, table(current)
IF (angle <= table(current)) AND (angle > table(previous)) THEN
ENDIF
Modify the program to display degrees with ASCII character 176, the ° symbol.
span = table(current) - table(previous)
angleOffset = angle - table(previous)
EXIT
Chapter 4: Hitachi HM55B Compass Module · Page 143