Freenove Ultimate Starter Kit, Руководство пользователя

Страница: 219 / 286

219 Chapter 19 74HC595 & LED Matrix █ www.freenove.com
support@freenove.com █
80
81
e x cept KeyboardInterrupt :
destroy ()
The first “for” cycle in the “while” cycle is used to display a static smile. Display column information from left
to right, one column by one column, totally 8 columns. Repeat 500 times to ensure display time enough.
f o r j i n range ( 0 , 500 ): # Repeat enough times to display the smiling face a period
of time
x = 0x80
f o r i i n range ( 0 , 8 ):
GPIO . output ( latchPin , GPIO . LOW )
shiftOut ( dataPin , clockPin , MSBFIRST , pic [ i ]) #first shift data of line
information to first stage 74HC959
shiftOut ( dataPin , clockPin , MSBFIRST ,~ x ) #then shift data of column
information to first stage 74HC959
GPIO . output ( latchPin , GPIO . HIGH ) # Output data of two stage 74HC595 at the
same time.
time . sleep ( 0.001 ) # display the next column
x > > = 1
The second “for” cycle is used to display scrolling characters "0-F", totally 18*8=144 columns. Display the 0-
8 column, 1-9 column, 2-10 column...... 138-144 column in turn to achieve scrolling effect. The display of
each frame is repeated a certain number of times, and the more times the number of repetitions, the longer
the single frame display, the slower the rolling.
f o r k i n range ( 0 , len ( data )- 8 ): #len(data) total number of “ O-F ” columns.
f o r j i n range ( 0 , 20 ): # times of repeated displaying LEDMatrix in every frame,
the bigger the “ j ” , the longer the display time
x = 0x80 # Set the column information to start from the first column
f o r i i n range ( k , k + 8 ):
GPIO . output ( latchPin , GPIO . LOW )
shiftOut ( dataPin , clockPin , MSBFIRST , data [ i ])
shiftOut ( dataPin , clockPin , MSBFIRST ,~ x )
GPIO . output ( latchPin , GPIO . HIGH )
time . sleep ( 0.001 )
x > > = 1