28029 Parallax Inc, 28029 Datasheet - Page 208

• 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

Page 196 · Smart Sensors and Applications
ACTIVITY #4: GAME CONTROL
Here are the rules of this Activity's tilt-controlled game example, shown in Figure 12.
Tilt your board to control the asterisk. If you get through the maze and place the asterisk
on any of the "WIN" characters, the "YOU WIN" screen will display. If you bump into
any of the pound signs "#" before you get to the end of the maze, the "YOU LOSE"
screen is displayed. As you navigate the maze, try to move your asterisk game character
through the dollar signs "$" to get more points.
Converting BubbleGraph.bs2 into TiltObstacleGame.bs2
TiltObstacleGame.bs2 is inarguably a hopped-up version of BubbleGraph.bs2. Here is a
list of the main changes and additions:
•
•
•
•
Change the graph into a maze.
Add two backgrounds for win and lose to the EEPROM data.
Give each background a Symbol name.
Write a game player code block that detects which background character the
game character is in front of and uses that information to enforce the rules of the
game.
MIN and Negative Numbers
A two’s complement "gotcha" to avoid is subtracting 1 from 0 and then setting the MIN value
afterwards. Remember from Chapter 3 that the two’s complement system stores the signed
value -1 as 65535. That’s why the MIN value was set to 1 before subtracting 1. The result is
then a correct minimum of 0. The same technique was used for setting the
even though there really isn’t a problem with y + 1 MAX 10.
MAX
values