Datasheet

Chapter 3: EEPROM Tricks and Program Tips · Page 111
Example Program: QtiPulseTrickLeft.bs2
The QtiPulseTrickLeft.bs2 program verifies that this technique works. Examine it
carefully. Especially make sure you can match the commands that deal with P5 and P9 to
the timing diagram in Figure 3-15.
√ Make sure the left QTI is over the black surface in your sumo ring.
√ Enter, save, and run QtiPulseTrickLeft.bs2.
√ Verify that the Debug Terminal shows that the
qtiStateLeft variable is 1
when the left QTI sees black and 0 when it sees white.
' Applied Robotics with the SumoBot - QtiPulseTrickLeft.bs2
' {$STAMP BS2} ' Target device = BS2
' {$PBASIC 2.5} ' Language = PBASIC 2.5
qtiStateLeft VAR Bit ' Store left QTI state
time VAR Word ' Store QTI decay time
threshold VAR Word ' Store b/w threshold
' Calibrate QTIs
HIGH 10 ' Turn on left QTI
HIGH 9 ' Discharge QTI capacitor
PAUSE 1 ' Wait for discharge
RCTIME 9, 1, time ' Vo decay time as cap charges
threshold = time / 4 ' Use to set threshold
IF threshold > 220 THEN ' Account for code overhead
threshold = threshold - 220
ELSE
threshold = 0
ENDIF
' Main Routine
DO
HIGH 9 ' Discharge QTI capacitor
PAUSE 1 ' Wait for discharge
INPUT 9 ' Start RC decay
PULSOUT 6, threshold ' Wait until threshold time
qtiStateLeft = IN9 ' Save state of P9
DEBUG HOME, ? qtiStateLeft ' Display state of P9
PAUSE 100 ' Delay for slower PCs
LOOP