rtcgpio

#!/usr/bin/env python

from smbusf import SMBus
from datetime import datetime, timedelta
from prtc import readrtc, writealm, readalm
from prtc import enablealm0, enablealm1, disablealm0, disablealm1
from prtc import enablesqw, disablesqw, mfpoutput
from papirus import Papirus
from pwrite_text import write_text, replace_line, update_lines
import os
import time
import RPi.GPIO as GPIO
import threading

def alm_callback(channel):
  global nrint, alm0time, alm1time
  if nrint == 0:
    # If you want to use both alarms to trigger the interrupt, then only one alarm can be enabled.
    # See the datasheet section 5.5 for details.
    # On the first interrupt disable alarm 0 en enable alarm 1
    disablealm0(i2cbus)
    enablealm1(i2cbus)
    alm0time = readrtc(i2cbus).strftime('%H:%M:%S') + ' UTC'
  elif nrint == 1:
    alm1time = readrtc(i2cbus).strftime('%H:%M:%S') + ' UTC'
  nrint = nrint + 1

def sqw_callback(channel):
  global nrint
  nrint = nrint + 1

def mfpoutputtask():
  for i in range(4):
    mfpoutput(i2cbus, 0)
    time.sleep(0.5)
    mfpoutput(i2cbus, 1)
    time.sleep(0.5)
  for i in range(6):
    mfpoutput(i2cbus, 0)
    time.sleep(1)
    mfpoutput(i2cbus, 1)
    time.sleep(1)
  mfpoutput(i2cbus, 0)
  mfpoutput(i2cbus, 1)

i2cbus = SMBus(1)
papirus = Papirus()
papirus.clear()
GPIO.setmode(GPIO.BCM)
GPIO.setup(27, GPIO.IN)

# --------- 1. Use of the two alarms ---------

# Set up the GPIO 27 interrupt and disable both alarms on the MCP7940N

nrint = 0
GPIO.add_event_detect(27, GPIO.FALLING, callback = alm_callback)
disablealm0(i2cbus)
disablealm1(i2cbus)

# Set the two alarm times

dtrtc = readrtc(i2cbus)
alarm0 = dtrtc + timedelta(seconds = 15)
alarm1 = dtrtc + timedelta(seconds = 25)
writealm(i2cbus, 0, alarm0)
writealm(i2cbus, 1, alarm1)

# Display the two alarm times on the Papirus diplay

alm0time = readalm(i2cbus, 0).strftime('%H:%M:%S')
alm1time = readalm(i2cbus, 1).strftime('%H:%M:%S')
write_text(papirus, 'Alarm Times Set:', x=20)
replace_line(papirus, 15, 20, 'Alm0: ' + alm0time + ' UTC')
replace_line(papirus, 15, 40, 'Alm1: ' + alm1time + ' UTC')
update_lines(papirus)

# Enable alarm 0
enablealm0(i2cbus)

# Display the hardware clock time and wait for the 2 alarms
prevsec = -1
alm0time = alm1time = ''
while nrint <= 2:
  dtrtc = readrtc(i2cbus)
  if dtrtc.second != prevsec:
    replace_line(papirus, 60, 150, dtrtc.strftime('%H:%M:%S') + ' UTC')
    prevsec = dtrtc.second
    if alm0time != '':
      replace_line(papirus, 15, 80, 'Alm0 at ' + alm0time)
      alm0time = ''
    if alm1time != '':
      replace_line(papirus, 15, 100, 'Alm1 at ' + alm1time)
      alm1time = ''
    update_lines(papirus)
    if nrint == 2:
      break
  time.sleep(0.1)
 
GPIO.remove_event_detect(27)
time.sleep(0.5)
replace_line(papirus, 60, 150, '')
update_lines(papirus)
time.sleep(2)

# --------- 2. 1 Hz swuare wave ---------

write_text(papirus, '1 Hz square wave', x=15)

GPIO.add_event_detect(27, GPIO.FALLING, callback = sqw_callback)
enablesqw(i2cbus)

nrint = prevnrint = 0
prevsec = -1
while nrint < 21:
  dtrtc = readrtc(i2cbus)
  if dtrtc.second != prevsec:
    replace_line(papirus, 60, 150, dtrtc.strftime('%H:%M:%S') + ' UTC')
    prevsec = dtrtc.second
    if nrint != prevnrint:
      replace_line(papirus, 60, 65, 'Interrupt ' + format(nrint))
      prevnrint = nrint
    update_lines(papirus)
  time.sleep(0.1)

GPIO.remove_event_detect(27)
disablesqw(i2cbus)
time.sleep(0.5)
replace_line(papirus, 60, 150, '')
update_lines(papirus)
time.sleep(2)

# --------- 3. Set mfp output directly ---------

write_text(papirus, 'Programmed output', x=20)

GPIO.add_event_detect(27, GPIO.FALLING, callback = sqw_callback)

t = threading.Thread(target=mfpoutputtask)
t.start()

nrint = prevnrint = 0
prevsec = -1
while t.isAlive():
  dtrtc = readrtc(i2cbus)
  if dtrtc.second != prevsec:
    replace_line(papirus, 60, 150, dtrtc.strftime('%H:%M:%S') + ' UTC')
    prevsec = dtrtc.second
    if nrint != prevnrint:
      replace_line(papirus, 60, 65, 'Interrupt ' + format(nrint))
      prevnrint = nrint
    update_lines(papirus)
  time.sleep(0.1)

replace_line(papirus, 60, 150, '')
update_lines(papirus)
time.sleep(2)

write_text(papirus, 'End of Demo', x=50, y=papirus.height/2 - 10)