Using a timer interrupt with KDS and K64F

Another demo that I saw while at the Freescale Tech Day was also pretty simple, but already moving a step beyond the traditional Arduino examples. It’s just blinking a LED, but rather than the “brute force” approach of switching the pin then forcing a wait before switching it again (the algorithm in the classic Arduino …

Continue reading ‘Using a timer interrupt with KDS and K64F’ »

A first project with FRDM-K64F and Kinetis Design Studio

Today, I thought I’d have a go at running one of the simple demonstrations I saw at the recent Freescale Tech Day in Milton Keynes. I have a FRDM-K64F development board which I bought a few weeks ago, and my fresh installation of the KDS IDE. The K64F is a lovely board with a powerful …

Continue reading ‘A first project with FRDM-K64F and Kinetis Design Studio’ »

Build an ‘Arduino’ on a Raspberry Pi

This is, after all, supposed to be a blog about Raspberry Pi. With all the stuff about Arduino and Atmel AVR chips, you might think I have wandered off. However, just to prove that Pi and ‘Duino work well together, here’s how I hand-built a board to sit on the Raspberry Pi GPIO pins and …

Continue reading ‘Build an ‘Arduino’ on a Raspberry Pi’ »

Driving a LED array from a BeagleBone Black

Over a month ago, now, I had a brief play with my Beaglebone Black. It took me a while but I just about got to the point of flashing an LED. That was enough at the time, but now I want to do something more interesting. So I thought I’d start by doing some patterns …

Continue reading ‘Driving a LED array from a BeagleBone Black’ »

Repairing a faulty “flowing water light” board

For my next experiments with LEDs and PWM I need more lights. When I bought the “flowing water light” I also bought a second one, but I hadn’t bothered assembling it yet. Naively I thought it would be as straight-forward as making the first one. I assembled the board (as far as I can tell) …

Continue reading ‘Repairing a faulty “flowing water light” board’ »

Using bit-angle PWM to drive GPIO pins

Although yesterday’s post was a reasonable introduction to bit-angle PWM, showing a pattern of characters on a console screen is hardly the most exciting or useful thing. So today I shall try to use the same code to drive something a bit more fun. I still had the “flowing water light” lying around, which I …

Continue reading ‘Using bit-angle PWM to drive GPIO pins’ »

Efficient software PWM with bit-angle modulation

It is a few months now since I last had a play with pulse-width modulation (PWM). At the time I was concerned by the amount of processing power used by the simplistic approach I had implemented, so I abandoned the exercise. Luckily, there are more efficient ways to do software PWM. One of the most …

Continue reading ‘Efficient software PWM with bit-angle modulation’ »

Driving a 7219 LED matrix from a Raspberry Pi

Flushed with my success in getting data displayed on my cheap LED matrix using a Bus Pirate, I decided that the next step was to see if I could get it working with a Raspberry Pi. Looking around for useful resources to get me started I found: Understanding SPI on the Raspberry Pi from Gordon’s …

Continue reading ‘Driving a 7219 LED matrix from a Raspberry Pi’ »

Testing a MAX7219 LED array with Bus Pirate

After thinking about how to drive the MAX7219 LED array I built yesterday, it occurred to me that maybe this is an ideal time to get to the bottom of how to use the Bus Pirate board that I failed to use with a MCP3002 ADC chip. This time I was determined to get it …

Continue reading ‘Testing a MAX7219 LED array with Bus Pirate’ »

Building a MAX7219 LED array

Time for a bit more soldering, I think. I couple of months ago I bought a little MAX7219 LED array kit from ebay for a couple of pounds. They are all over ebay and aliexpress. As kits go it is very simple – a resistor, two capacitors, some sockets and some optional connectors. Soldering it …

Continue reading ‘Building a MAX7219 LED array’ »