STEMBoT STEMBoT 2, Manual

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STEMBoT 2 User’s Manual
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4.3.2.0 Text
Writing text to the LCD is done through the ​
print()
​
function of the ​
graphics()
​
module.
The ​
print()
​
function takes four parameters: the string to be written, the x location, the y
location, and the color. For ease of use, three additional functions are provided: printTop(),
printMiddle(), and printBottom(). These functions accept only two arguments, the string and
color, and print to the top of the LCD, the middle, and the bottom, respectively.
# This program is for demonstrating the operation of the LCD by
# printing "Hello, world!" in white text on a blue background.
import graphics
#imports the module used for LCD operations
import color #imports the module for LCD colors
import uasyncio #imports the module used for concurrent programming
bgColor=color.RGB(0,0,255) #blue
textColor=color.RGB(255,255,255) #white
async def main():
#main function header
graphics.paint(bgColor) #fill screen with color
graphics.print("Hello, World!",40,120,textColor) #print to LCD
Program 7: ​ Hello, world!
Text that has been written using the ​
print()
​
function can be erased using the ​
erase()
function. This function accepts four arguments as well: the number of characters to be erased,
the x location, the y location, and the color. The x and y locations should be the same as those
sent to the
​
print() ​
function. The color should be the background color on which the characters
have been written.
For an example using the
​
print()
​
and
​
erase()
​
functions, set up a serial connection to
the SB2, and type in the following lines:
import graphics
import color
red=color.RGB(255,0,0)
black=color.RGB(0,0,0)
graphics.paint(red)
graphics.print(“Hello, world!”,40,120,black)
Now, after making sure the text has shown up, send the following command to the SB2:
graphics.erase(13,40,120,red)
This line tells the SB2 how many characters there are in “Hello, world!” (be sure to
include spaces), the placement of the text, and the background color. The
​
erase()
​
function
works by drawing a filled rectangle (section 4.3.3.1) around the previously printed text. If a color
other than the background color is sent, the LCD will simply print a box of that color over the
text.
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Revision 1.1.0 : January 2021