Micro Dot Phat running with Arduino

Some has asked if a Micro Dot Phat can run with Arduino

see video of a Micro Dot Phat here:
Youtube Micro Dot Phat Arduino

can post Arduino sketches if interested

Nice work! I’m intimately familiar with how insane the LED mapping is on this pHAT :D So well done for getting it up and running.

Awesome work! Would love to see some code examples for getting this up and running. Thanks!

the code for the NTP Clock is as follows, the hardware is an Adafruit Huzzah w/ ESP8266 and a MicroDot Phat

the key point to remember is that with each pair of 5x7 matrixes one uses row bit mapped data and the other uses column bit mapped data. so to save space there is column data bit mapped data and when a row data set is required a short routine converts the column data to row data and that is sent via I2C.

posted to GitHub at: https://github.com/clarktans/microdot-clock

Very nice and easy to set up.
Any suggestions on how to address the decimal points?

Making some progress on the decimal points. For displays 1,3 and 5 the decimal point is addressed at bit 7 (msb) of column 8.

You would think that for displays 2,4 and 6 the decimal point would be at bit 8 of row 7 but it doesn’t seem to be… Anyone else looked at this or have any clues?

According to my comments in the code (I can’t actually recall what the layout is) it should be bit 7 of col 8 on even numbered displays- I can’t even make sense of the comments in retrospect, so let’s look at the code:

So for left matrix it looks like bit 8 of row 7, and for right matrix it looks like bit 7 of row 8.

Thanks for the work. It’s a great.
I have a question: Is it possible to reduce the brightness parameters?

It is possible to dim the leds using control registers 0dh and 19h, see pdf at


Thanks for the quick response.