TangNano 9K controlling multiple LED targets Part 3 of 3

Background

This is the 3rd article on how to use a Tang9k to control LEDs.

Blinkt!

The Blinkt! board has 8 APA102 LEDs connected to each other via CLK, Data, VCC and GND. A simple serial protocol is used to change the color of each led in the serial stream. There are number of articles on the web that describe how to create a serial stream to control the LEDs. This article does not cover the protocol.

The Blinkt! requires 4 connections, 5V, ground, data and serial. The pin out is detailed here. Connect the 5v to the Tang9K 5v, connect ground, and the clk to 55, and data to 56 of the Tang9k. To make this easier, took a perf board and some header pins and made a board.

Controlling the LEDs

There are two python scripts, blinktTester.py and allTest.py allTest.py toggles all leds at the same time. The same API used for the blinkt!, there are 8 memory registers for each LED. To update the LED, a write to address 0x220 sends the serial string to the blinkt! led.

Here is a trace for the neoPX and Blinkt!

Here is just the blinkt! stream

There are 10 frames, first frame is all 0's for the start of header, then followed by 8 leds, then last frame is all FFs. For this, demo, put a delay between each frame to show each sequence.