1  # Simple script using GPS timestamps as RTC time source
 2  # The GPS timestamps are available without a fix and keep the track of
 3  # time while there is powersource (ie coin cell battery)
 4  
 5  import time
 6  import board
 7  import busio
 8  import rtc
 9  import adafruit_gps
10  
11  uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=10)
12  # i2c = busio.I2C(board.SCL, board.SDA)
13  
14  gps = adafruit_gps.GPS(uart, debug=False)
15  # gps = adafruit_gps.GPS_GtopI2C(i2c, debug=False)  # Use I2C interface
16  
17  gps.send_command(b"PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0")
18  gps.send_command(b"PMTK220,1000")
19  
20  print("Set GPS as time source")
21  rtc.set_time_source(gps)
22  the_rtc = rtc.RTC()
23  
24  last_print = time.monotonic()
25  while True:
26  
27      gps.update()
28      # Every second print out current time from GPS, RTC and time.localtime()
29      current = time.monotonic()
30      if current - last_print >= 1.0:
31          last_print = current
32          if not gps.timestamp_utc:
33              print("No time data from GPS yet")
34              continue
35          # Time & date from GPS informations
36          print(
37              "Fix timestamp: {:02}/{:02}/{} {:02}:{:02}:{:02}".format(
38                  gps.timestamp_utc.tm_mon,  # Grab parts of the time from the
39                  gps.timestamp_utc.tm_mday,  # struct_time object that holds
40                  gps.timestamp_utc.tm_year,  # the fix time.  Note you might
41                  gps.timestamp_utc.tm_hour,  # not get all data like year, day,
42                  gps.timestamp_utc.tm_min,  # month!
43                  gps.timestamp_utc.tm_sec,
44              )
45          )
46  
47          # Time & date from internal RTC
48          print(
49              "RTC timestamp: {:02}/{:02}/{} {:02}:{:02}:{:02}".format(
50                  the_rtc.datetime.tm_mon,
51                  the_rtc.datetime.tm_mday,
52                  the_rtc.datetime.tm_year,
53                  the_rtc.datetime.tm_hour,
54                  the_rtc.datetime.tm_min,
55                  the_rtc.datetime.tm_sec,
56              )
57          )
58  
59          # Time & date from time.localtime() function
60          local_time = time.localtime()
61  
62          print(
63              "Local time: {:02}/{:02}/{} {:02}:{:02}:{:02}".format(
64                  local_time.tm_mon,
65                  local_time.tm_mday,
66                  local_time.tm_year,
67                  local_time.tm_hour,
68                  local_time.tm_min,
69                  local_time.tm_sec,
70              )
71          )