Real Time Clock¶

The PiicoDev Real Time Clock (RV-3028) keeps track of the date and time, even while the micro:bit is turned off.

Possible uses:

• clocks and alarm clocks
• timetable and bell reminders
• data loggers that record when each reading was taken
• countdowns to a date

Connect it¶

1. Connect the clock to the PiicoDev adapter with a PiicoDev cable. See Using PiicoDev.
2. Upload these files to the micro:bit with main.py:
   • PiicoDev_Unified.py
   • PiicoDev_RV3028.py
3. The clock keeps time using a small built-in backup power store, so set the time once and it keeps counting.

Set it up¶

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

rtc = PiicoDev_RV3028()

Methods¶

The date and time are stored in properties. Set them, then call setDateTime(); or call getDateTime(), then read them.

setDateTime()¶

Writes the date and time properties to the clock.

Run this once to set the clock. Change the values to the current date and time first.

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

# Setup
rtc = PiicoDev_RV3028()
rtc.year = 2026
rtc.month = 9
rtc.day = 28
rtc.hour = 14
rtc.minute = 30
rtc.second = 0
rtc.weekdayName = "Monday"
rtc.ampm = "24"
rtc.setDateTime()

timestamp()¶

Returns the date and time as one string, in the format YYYY-MM-DD HH:MM:SS.

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

# Setup
rtc = PiicoDev_RV3028()

# Main loop
while True:
    print(rtc.timestamp())
    sleep(1000)

getDateTime()¶

Reads the date and time from the clock into the year, month, day, hour, minute, second and weekday properties. weekday holds the day as a number from 0 (Monday) to 6 (Sunday), and weekdayName gives its name, such as "Monday".

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

# Setup
rtc = PiicoDev_RV3028()

# Main loop
while True:
    rtc.getDateTime()
    print(rtc.hour, rtc.minute)
    sleep(1000)

getUnixTime()¶

Returns the clock's Unix time: the number of seconds since 1 January 1970.

Unix time is one number that counts seconds. It makes working out the time between two events easy: subtract one from the other. The clock keeps Unix time on a separate counter from the date and time, so it only matches the date and time once we set it with setUnixTime().

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

# Setup
rtc = PiicoDev_RV3028()

# Main loop
while True:
    print(rtc.getUnixTime())
    sleep(1000)

setUnixTime()¶

Sets the clock's Unix time counter. It doesn't change the date and time that timestamp() and getDateTime() read.

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from microbit import *
from PiicoDev_RV3028 import PiicoDev_RV3028

# Setup
rtc = PiicoDev_RV3028()
rtc.setUnixTime(1790000000)

# Main loop
while True:
    print(rtc.getUnixTime())
    sleep(1000)

Documentation¶

Documentation is the official guide written by the people who made the code library, and we can use it to look up every method and its parameters, including ones that aren't covered on this page.

• PiicoDev RV-3028 driver

Exercises¶

Starter files are in the rtc folder of your tutorial files. Solutions are on the Exercise Solutions page.

Exercise 1¶

Starter: rtc/ex1_clock

Can you make a clock that shows the time when button A is pressed and the date when button B is pressed?

Exercise 2¶

Starter: rtc/ex2_greeting

Can you make the micro:bit greet you when button A is pressed? It should show Good morning before 12 pm, Good afternoon from 12 pm until 6 pm, and Good evening after 6 pm.