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|
#!/usr/bin/env python
# File rpi_7219b.py
# http://www.bristolwatch.com/index.htm
# By Lewis Loflin - lewis@bvu.net
# Output time from system clock.
# Two bytes are shifted in first being address, second being data.
# Works the same as two 74165 SSRs in series or 16-bits.
# LD "pulseCS()" clocks 16-bit address/data into working registers.
# access to GPIO must be through root
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
LATCH = 24 # CS
CLK = 23
dataBit = 19 # DIN
GPIO.setup(LATCH, GPIO.OUT) # P0
GPIO.setup(CLK, GPIO.OUT) # P1
GPIO.setup(dataBit, GPIO.OUT) # P7
# Setup IO
GPIO.output(LATCH, 0)
GPIO.output(CLK, 0)
def pulseCLK():
GPIO.output(CLK, 1)
# time.sleep(.001)
GPIO.output(CLK, 0)
return
def pulseCS():
GPIO.output(LATCH, 1)
# time.sleep(.001)
GPIO.output(LATCH, 0)
return
# shift byte into MAX7219
# MSB out first!
def ssrOut(value):
for x in range(0,8):
temp = value & 0x80
if temp == 0x80:
GPIO.output(dataBit, 1) # data bit HIGH
else:
GPIO.output(dataBit, 0) # data bit LOW
pulseCLK()
value = value << 0x01 # shift left
return
# initialize MAX7219 4 digits BCD
def initMAX7219():
# set decode mode
ssrOut(0x09) # address
# ssrOut(0x00); // no decode
ssrOut(0xFF) # 4-bit BCD decode eight digits
pulseCS();
# set intensity
ssrOut(0x0A) # address
ssrOut(0x04) # 9/32
pulseCS()
# set scan limit 0-7
ssrOut(0x0B); # address
ssrOut(0x07) # 8 digits
# ssrOut(0x03) # 4 digits
pulseCS()
# set for normal operation
ssrOut(0x0C) # address
# ssrOut(0x00); // Off
ssrOut(0x01) # On
pulseCS()
# clear to all 0s.
for x in range(0,9):
ssrOut(x)
ssrOut(0)
pulseCS()
return
def writeMAX7219(data, location):
ssrOut(location)
ssrOut(data)
pulseCS()
return
def displayOff():
# set for normal operation
ssrOut(0x0C) # address
ssrOut(0x00); # Off
# ssrOut(0x01) # On
pulseCS()
def displayOn():
# set for normal operation
ssrOut(0x0C) # address
# ssrOut(0x00); # Off
ssrOut(0x01) # On
pulseCS()
initMAX7219()
# time returned as string
# But order is reversed relative to MAX7219.
str1 = time.strftime("%H:%M:%S")
# str2 = time.strftime("%d:%m:%Y")
print (str1)
# print len(str1) # 8
# x is digit position must be 1 to 8
# y is used for string pointer
while 1:
y = 7
for x in range(1, 9):
if str1[y] == ":":
# output "-"
writeMAX7219(10, x)
y = y - 1
continue # back to if
# convert y char to integer
writeMAX7219(int(str1[y]), x)
y = y - 1
str1 = time.strftime("%H:%M:%S")
print (str1)
print ("Stop")
time.sleep(20)
displayOff() |
Python, GPIO, Max7221 et 6 afficheurs 7 segments
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