The ‘standard’ binary files for many tools are S19, binary or Intel Hex files. Especially for S19 and Intel Hex it can be useful to control the amount of data per line. By default, the GNU objcopy creates files with a line length of 44 characters:
default objcopy binary file line length
But it is possible to have Intel Hex files with an custom line length using the SRecord utility, and this is what this article is about.
The ‘Black Magic Probe’ (or in short: BMP) is a very small and open source JTAG/SWD debug probe with a build-in GDB Server. I saw that probe referenced in different places, so I thought I try it out with a few of my NXP LPC and Kinetis boards:
BMP with LPC and Kinetis Boards
With the cost of an single pin, many ARM Cortex-M boards including the NXP i.MX RT1064 can produde SWO data: think about a pin able to stream data out of the chip in realtime. For example interrupt activity which otherwise might be hard to capture:
SWO Interrupt Trace
The ‘Internet of Things’ is coming! It started as an overused marketing hype with no real use case (who needs internet connected fridges? Who wants the internet connected toilet paper?).
New ‘things’ start to pop up, useful or not: From smart bulbs (Philips Hue), thermostats (Nest), smart TV (Samsung and others) up to voice assistants (Alexa, Cortana, Google). You might even have installed one of these, right? What about temperature and humidity sensors? Probably there is nothing wrong with that?
But what would you think if one morning you find a strange unknown device installed under your working desk, connected to the cloud and internet?
IoT Device attached under a working desk
In a modern development workflow both command-line and a graphical user interface has its place. On the GUI side, Eclipse is famous that it offers many different ways to accomplish something which is great. But sometimes I continue to use an old habit or way because I have missed that there is a newer and better way, and the MCUXpresso Eclipse IDE is no exception to that. In this article I show a few ways how to use the mouse even more productive.
Project Settings
In my previous articles I have used the command line on Linux to build and debug NXP MCUXpresso SDK applications. In this article I’m running code on NXP i.MX RT1064 in RAM or FLASH.
i.MXRT1064 board with LPC845-BRK as debug probe
The LPC55S69-EVK board comes on-board debug probe. The board includes the LPC4322JET100 device which acts like NXP LPC-Link2 debug probe:
LPC4322JET100 on LPC55S69-EVK
But it is easily possible to use the board with an external debug probe or re-program the onboard one as a SEGGER J-Link debug probe.
There are different ways to ruin a Linux system. For the Raspberry Pi which uses a micro SD card as the storage device by default, it comes with two challenges:
For problem one I do I have a mitigation strategy (see “Log2Ram: Extending SD Card Lifetime for Raspberry Pi LoRaWAN Gateway“). Problem two can occur by user error (“you shall not turn it off without a sudo poweroff!”) or with the event of a power outage or black out. So for that problem I wanted to build a UPS for the Raspberry Pi.
Raspberry Pi with UPS System and tinyK22
For the long Easter weekend I have organized a new toy: the NXP LPC55S69-EVK board: a dual ARM Cortex-M33 running at 100 MHz with ARM TrustZone:
LPC55S69 Microcontroller
In “Tutorial: MCUXpresso SDK with Linux, Part 1: Installation and Build with Maked” I used cmake and make to build the SDK application. In this part I’m going to use the command line gdb to debug the application on the board.
Cross-Debugging with GDB
I admit: my work laptop machine is running a Windows 10 OS by default. But this does not prevent me running Linux in a Virtual Machine (VM). Each host platform has its benefits, and I don’t feel biased to one or the other, but I have started using Ubuntu more and more, simply because I have worked more on Embedded Linux projects. While I have used mostly Windows with Eclipse for NXP LPC, Kinetis and i.MX platforms in the past, I started using Ubuntu too from last year with the NXP MCUXpresso SDK. I did not find much documentation about this on the web, so I thought it might be a good idea to write a tutorial about it. So here we go…
Building NXP MCUXpresso SDK on Linux Ubuntu
My LoRaWAN gateway (“Contributing an IoT LoRaWAN Raspberry Pi RAK831 Gateway to The Things Network” is running and working great now for more than a month and it already has transmitted more than 30k messages:
Gateway Overview
This creates a lot of log entries on the micro SD card of the Raspberry Pi. To avoid writing too many times log data, I have installed Log2Ram.
My mantra is *not* to use any floating point data types in embedded applications, or at least to avoid them whenever possible: for most applications they are not necessary and can be replaced by fixed point operations. Not only floating point operations have numerical problems, they can lead to performance problems as in the following (simplified) example:
#define NOF 64
static uint32_t samples[NOF];
static float Fsamples[NOF];
float fZeroCurrent = 8.0;
static void ProcessSamples(void) {
int i;
for (i=0; i<NOF; i++) {
Fsamples[i] = samples[i]*3.3/4096.0 - fZeroCurrent;
}
}
In the IoT world, it is all about security, connectivity and low power. LoRaWAN with the Things Network is able to connect devices over several kilometers, and I’m running my gateway for it already (see “Contributing an IoT LoRaWAN Raspberry Pi RAK831 Gateway to The Things Network“). This tutorial is about building a BLE+LoRaWAN+GPS sensor node with GNU tools and Eclipse:
LoRa+BLE with RAK813 and LPC845
For some projects it is not possible to have the device under debug available on my desk: the board might be in another room, on another site or in a place where physical access is not possible or even dangerous. In that case an IP-based debug probe (see Debugging ARM Cores with IP based Debug Probes and Eclipse) is very useful: as long as I can access its IP address, that works fine. It is an excellent solution even if the board is moving or rotating: hook it up to a WLAN access point and I still can use it as it would be on my desk.
But what if I have a debug probe only connected to USB? This article shows how to turn a USB debug probe into a IP-based debug solution: that way I can easily debug a board from remote, connected to the network:
IP Based Debugging with USB Debug Probe
LoRa and LoRaWAN is getting the de-facto wireless IoT network in my area. No surprise that traditional telecom providers like Swisscom trying to monetize the ‘Internet of Things’ area. Luckily there is an open and free alternative: https://www.thethingsnetwork.org/. Volunteers, enthusiasts and members in the different TTN communities build gateways and offer free LoRaWAN network access. I wanted to contribute to that grassroots movement with building my gateway, providing LoRaWAN access to my neighborhood.
LoRaWAN TheThingsNetwork Gateway
Most of the time software needs some way to configure things: depending on the settings, the software will do different things. For example the software running on the microcontroller on top of the Raspberry might have the OLED LCD available or not:
Raspberry Pi and tinyK22 (NXP Kinetis K22FN512) with OLED LCD
How can I deal with this in my application code? Continue reading
By default, when debugging an embedded application, the target usually stops at main():
stopped in main
That’s usually fine, but what if I want to debug the code out of reset?
Sometimes I start a project with an ARM microcontroller, and in the middle of the project I find out that it was a wrong choice at the beginning and I need to switch the microcontroller derivative or even the used ARM core. With little knowledge of the project structure and the files needed, such a switch is not the easiest thing, but definitely possible.
switching cores
The NXP LPC845-BRK board is a sub-$6 breadboard friendly development board with an ARM Cortex-M0+ on it. This tutorial is about developing a ‘blinky’ on it using MCUXpresso.
Binky on NXP LPC845-BRK Board
