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RocNetNode Fast Clock


The ADAFRUIT 0.56" 4-DIGIT 7-SEGMENT DISPLAY W/I2C BACKPACK can be used as I2C Fast Clock.
If the clock runs with real time, divider = 1, the colon will blink every second.
In case the divider > 1 the colon will be on constantly, and the dots will step with a 1 second frequency to signal 'Fast'.


The following information can be iterated every 10 real seconds if enabled:

In case there was no clock synchronisation within 70 seconds the display will show idle with a looping dash.
This is also the case after the RocNetNode has been started until a clock synchronisation came in.
The looping dash is also an indicator that the I2C bus works as expected.


If a Weather theme with color table is active, the temperature and brightness are used for the clock displays.


Because this board does not feature an I2C buffer chip, it can interfere with other I2C connected boards.
A possible solution is by using the GCA-PI03 board:

Just prepare a short 4 wire connector cable with GND, VCC, SDA, SCL and the fastclock works in a safe way.


The number of connected displays are scanned at RocNetNode startup, and therefor they must be connected to the I2C bus before RocNetNode starts.
Make sure the display addressing starts with 0x70, default, and further displays should be addressed increased by one. Avoid gaps between the addressing to save I2C bandwidth.

The clock settings are used for all connected displays.


Enable the clock display update cycle.
If disabled the clock displays will show: - - - -


Show the date in the following format: DD.MM.


Show the temperature in the following format: -CC°


In case the clock is running faster then real time the four dots will blink in an endless loop.


The display brightness can be set in the range of 1 to 15.
A value of 15 is the max. brightness.

The brightness may be overwritten in case the Weather with Color table is active.


RJ12 PSK Wire Color Remark
1 1 VCC Red Plus
2 4 SCL Green I2C clock
3 2 GND Black Ground
4 3 SDA Yellow I2C data



Fast clock with divider > 1 Fast clock with time, date and temp.
rocnet/fastclock-en.txt · Last modified: 2021/09/20 08:53 by phil45