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
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.
The ARM TrustZone is an optional secu=rity feature for Cortex-M33 which shall improve the security for embedded applications running on microcontroller as the NXP LPC55S69 (dual-core M33) on the LPC55S69-EVK.
NXP LPC55S69-EVK Board
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
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
In “Debugging the RV32M1-VEGA RISC-V with Eclipse and MCUXpresso IDE” I described how to build and debug applications for the VEGA RISC-V board. In this article I describe how to enable FreeRTOS for RISC-V, based on the latest FreeRTOS V10.2.0 release.
Blinky with FreeRTOS on the VEGA RISC-V Board
The ARM Cortex cores are everywhere. I like (and use) them a lot. Don’t take me wrong: maybe ARM needs some competition? It is very refreshing to see that something new is getting a lot of attention: RISC-V!
RV32M1 (VEGA)
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
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?
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
The NXP LPC845-BRK board is a tiny an inexpensive (sub $6) breakout board. The board includes a CMSIS-DAP (LPC11U35) on-board debug probe which can be used as a debug probe to debug any NXP LPC, Kinetis or i.MX RT device 🙂
LPC845-BRK used to debug a Sumo Battle Robot
One great thing with that new NXP LPC845-BRK board is that it is possible to use it with any standard SWD/JTAG debugger, as it has the 10pin debug header present on the board. It is not populated by default, because the LPC845-BRK includes a CMSIS-DAP debug probe already. But if I want to use a SEGGER J-Link, a P&E Multilink or the NXP LPCLink2, this is certainly something to consider:
Debugging LPC845-BRK with LPC-Link2
I really love tiny and bread board friendly boards, especially if they are very affordable and can be use with Eclipse based tools. So I was excited to see the NXP LPC845-BRK board to be available at Mouser, so I ended up ordering multiple boards right away. Why multiple? Because they only cost CHF 5.95 (around $6)!
NXP LPC845-BRK Board
It is a common thing to boot a Linux system (see the Raspberry Pi) from a micro SD card. It is not that common for a microcontroller. The NXP i.MX RT ARM Cortex-M7 fills that gap between these two worlds. No surprise that it features a ROM bootloader which can boot from a micro SD card.
SD Card with i.MX RT1052
Most host or desktop systems (say Linux, Mac or Windows) have a normal use case where you start the operating system say in the morning and shut it down in the evening, and then you leave the machine. Embedded Systems are different: they are not attended, and they are supposed to run ‘forever’. Not every embedded system needs to run an OS (or in that world: Real-Time Operating System or RTOS), but the same applies here: after the RTOS is started, it is not intended that it will shutdown and restart. To the extend that you won’t they support the ‘shutdown’ and ‘restart’ functionality at all. In case of gathering coverage information this would be really useful:
coverage information from FreeRTOS application
In the case of FreeRTOS: what if I really need to shutdown the RTOS and restart it again, as by default this is not supported. This is what this article is about …
GDB supports a mode which allows the GDB debug client to read memory while the target is running. This allows features like ‘live variables’: that way I can see the variables refreshed and changing over time without halting the target. Another functionality which comes with that feature is to check stopped threads or to see all threads in the system.
multiple FreeRTOS threads in debug view
I’m using the VL6180X ToF (Time-of-Flight) sensors successfully in different projects. The VL6180X is great, but only can measure distances up to 20 cm and in ‘extended mode’ up to 60 cm. For a project I need to go beyond that, so the logical choice is the VL53L0X which measures between 30 cm and 100 cm or up to 200 cm. For this project I’m using the VL53L0X breakout board from Adafruit, but similar products are available e.g. from Pololu.
NXP K20dx128 with Adafruit VL53LOx tof sensor
Working with low power modes can be challenging. It can severely affect debugging capabilities of a microprocessor or microcontroller. I ported a FreeRTOS application using the Tickless Idle Mode to the NXP i.MX RT1064 board, and all of a sudden, the board was unresponsive to any debugger connection. Luckily the board was not really bricked, but it took me while to find a way to recover it. So for when you end up in a situation with a ‘bricked’ i.MX RT1064 board, this article might be helpful for you to recover it.
i.MX RT1064-EVK Board
