As a remote controller for the Sumo robot (see “Zumo Robot with Magnetic Encoders“) we have used so far a combination of NXP FRDM-KL25Z board and a Joystick Shield (see “Joystick Shield with nRF24L01 driving a Zumo Robot“). That solution was not ideal, so this weekend I created a 3D printed prototype:
tinyK20 Remote Controller
We are using robots to teach advanced embedded system programming at the Lucerne University (see “Sumo Robot Competition“). Students can buy the kit, and we are running out of available hardware. Time to produce a new series of robots :-). It took us a while to get to the next revision of the Zumo Robot, but finally the first one has been produced and assembled, and I think it is looking good :-).
Intro_Zumo_Robot
I’m using the tiny and inexpensive Nordic Semiconductor nRF24L01+ transceiver (see “Tutorial: Nordic Semiconductor nRF24L01+ with the Freescale FRDM-K64F Board“) in many projects: it costs less than $3 and allows me to communicate with a proprietary 2.4GHz protocol in a low power way (see “IoT: FreeRTOS Down to the Micro Amps“). I have that transceiver now running with the tinyK20 board too:
nRF24L01+ Transceiver with tinyK20
I’m using the FRDM-KL25Z in my classes, and that board is very popular: low price (<$15), reasonable features (48 MHz ARM Cortex M0+, 128 KByte of FLASH, 16 KByte of RAM), and many tutorials elsewhere and on McuOnEclipse :-).
For the next (Fall) semester I’m looking for alternative boards, and one is the Freescale (now NXP) FRDM-KL27Z:
FRDM-KL27Z with Box
I’m exploring the Kinetis SDK v2.0 (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). For this, I’m using the ‘standard’ way: blinking the LED on the board 🙂
Blinky on FRDM-K64F Board
To put the tinyK20 board with the NXP Kinetis K20 into bootloader mode, well someone could check the schematics, or follow this quick guide :-). In short, the pin PTB1 has to be pulled to Ground (GND) while powering the Kinetis K20. The pin PTB1 is on the outside row as below:
tinyK20 Bootloader Pins
I’m using Processor Expert components for nearly every Freescale (now NXP) projects: for S08, S12, ColdFire, DSC and especially all the different NXP Kinetis devices. Not only because it makes software development fast and easy and allows re-use of software, but as well because Processor Expert has a good way to pack and distribute software components. Unfortunately Processor Expert is not any more included for the new Kinetis devices (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). So I have looked into an alternative and hopefully vendor neutral way to build and distribute software packages using CMSIS-Pack.
CMSIS-Pack in Eclipse
In “openHAB RGB LED Light Cube with WS2812B and NXP Kinetis” I started experimenting Kinetis boards, a LED cube diffuser and Adafruit WS2812B NeoPixel LEDs. That worked well, but I was not to very happy about the visual effect. So here is my next version: I wanted to have control over each side of the cube. For this I have built a cube inside the cube with a 3D printed structure:
Bare LED Cube
I have been asked to provide a command line shell example for a bare-metal (no RTOS) application, so here we go!
Having a way to communicate to the firmware on a board is essential for most of my projects: it is simply, incredibly helpful and easy to do (see “A Shell for the Freedom KL25Z Board“). This tutorial shows how to add a simple command line shell to the NXP Freedom board which then can be extended as necessary.
Console Application
From my earlier work to use the NXP Kinetis with openHAB (see “Controlling NXP Freedom Board RGB LED with openHAB and Raspberry Pi“) it was only a small step to control a 20x20x20 cm light cube with 256 Adafruit WS2812 NeoPixels:
Kinetis RGB Cube with openHAB
MCU on Eclipse 