28029 Parallax Inc, 28029 Datasheet - Page 42

• 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 30 · Smart Sensors and Applications
The Scroll_Message Subroutine's Sliding Window
Let's say the shifting text display window in your LCD is four characters wide on the top
row because there are other messages that need to be displayed at all times on the LCD.
The task at hand is to slide the text through the smaller window without overprinting any
of the characters displayed outside it.
LOOP
RETURN
NEXT
PAUSE timeOff
SEROUT LcdPin, T9600, [cursorStart]
' This FOR...NEXT loop refreshes the message, shifted increment characters
' to the left each time through until the end of the EEPROM message.
' Then, it fills the display with space characters as the remainder of the
'
FOR pointer = head TO tail
NEXT
PAUSE timeOn
' Increment until at window-left
cursorStart = cursorStart - increment MIN windowLeft
tail = tail + increment
' Increment head pointer if tail pointer > window width.
IF tail > (windowRight - windowLeft) THEN
ELSE
ENDIF
SEROUT LcdPin, T9600, [" "]
IF (pointer <= (MessageEnd - MessageStart - 1)) THEN
ELSE
ENDIF
SEROUT LcdPin, T9600, [character]
head = 0
message shifts out to the window.
head = head + increment
READ pointer + MessageStart, character
character = " "
' Let characters fade away
' Rightmost character in window
' Give the characters some time
' Increment tail pointer
' Repeat scrolling loop