The NXP LPC55S69-EVK is a versatile board. In this article I show how it can be used with Adafruit TFT LCD boards, both with resistive and capacitive touch. For the software I’m using the open source LittlevGL GUI.
LPC55S69-EVK with Adafruit Touch LCD
In “Seeed Studio Arch Mix NXP i.MX RT1052 Board” and “Debug and Execute Code from FLASH on the Seeed Arch Mix NXP i.MX RT1052 Board” I have used the NXP LPC-Link2 to debug the Seeed Arch Mix board with the NXP i.MX RT1052, because the SEGGER J-Link does not work out-of-the box with the i.MX RT using QSPI Flash. This article shows how the J-Link connection can be changed from HyperFlash to work with QSPI Flash.
J-Link EDU Mini with Seeed i.MX RT1052
Bootloaders are a fine thing: With this I can load any applications I like. Power comes with some complexity, and a bootloader alone is a complex thing already. But this applies to the application part too: I need to link the application to a certain offset in the memory space so it can be loaded by the bootloader, plus the application typically needs to add some extra information to be used by the bootloader. This article describes how to build a bootloader application with Eclipse (MCUXpresso IDE) using the MCUXpresso SDK.
Build Configuration for Bootloader Application
Stack overflows are probably the number 1 enemy of embedded applications: a call to a a printf() monster likely will use too much stack space, resulting in overwritten memory and crashing applications. But stack memory is limited and expensive on these devices, so you don’t want to spend too much space for it. But for sure not to little too. Or bad things will happen.
The Eclipse based MCUXpresso IDE has a ‘Heap and Stack Usage’ view which can be used to monitor the stack usage and shows that a stack overflow happened:
Heap and Stack Usage
But this is using the help of the debugger: how to catch stack overflows at runtime without the need of a debugger? There is an option in the GNU gcc compiler to help with this kind of situation, even if it was not originally intended for something different. Continue reading
When Espressif released in 2014 their first WiFi ESP8266 transceiver, they took over at least the hobby market with their inexpensive wireless devices. Yet again, the successor ESP32 device is used in many projects. Rightfully there are many other industrial Wi-Fi solutions, but Espressif opened up the door for Wi-Fi in many low cost projects. Many projects use the ESP devices in an Arduino environment which basically means decent debugging except using printf() style which is … hmmm … better than nothing.
What is maybe not known to many ESP32 users: there *is* actually a way to use JTAG with the ESP32 devices :-). It requires some extra tools and setup, but with I have a decent Eclipse based way to debug the code. And this is what this article is about: how to use a SEGGER J-Link with Eclipse and OpenOCD for JTAG debugging the ESP32.
Robot with ESP32 and JTAG Debug Port
NXP has released an update of the Eclipse based V11 IDE. This is right on time for the new semester starting mid of September where this IDE will be used in several labs.
MCUXpresso IDE V11.0.1
The Espressif ESP32 devices are getting everywhere: they are inexpensive, readily available and Espressif IDF environment and build system actually is pretty good and working well for me including Eclipse (see “Building and Flashing ESP32 Applications with Eclipse“). The default way to program an ESP32 is to a) enter UART bootloader by pressing some push buttons and b) flash the application with ESP-IDF using a USB cable.
That works fine if the ESP32 is directly connected to the host PC. But in my case it is is behind an NXP Kinetis K22FX512 ARM Cortex-M4F microcontroller and not directly accessible by the host PC. So I had to find a way how to allow boot loading the ESP32 through the ARM Cortex-M which is the topic of this article.
TTGO ESP32 MICRO-D4 Module
The new semester is approaching in a very fast way, and so is the new lecture and lab module ‘Advanced Distributed Systems’ at the Lucerne University. For that module we are going to build a new ‘Sumo’ style robot with WLAN capabilities using the ESP32 chip. It will be a new robot PCB, and below is the current robot (based on NXP K22FX512) with the WLAN module connected to it:
Zumo connected to TTGO ESP32 module
It is great if vendors provide a starting point for my own projects. A working ‘blinky’ is always a great starter. Convenience always has a price, and with a ‘blinky’ it is that the code size for just ‘toggling a GPIO pin’ is exaggerated. For a device with a tiny amount of RAM and FLASH this can be concerning: will my application ever fit to that device if a ‘blinky’ takes that much? Don’t worry: a blinky (or any other project) can be easily trimmed down.
Binky on NXP LPC845-BRK Board
I use a ‘blinky’ project here just as an example: the trimming tips can apply to any other kind of projects too.
In my previous article “Debug and Execute Code from FLASH on the Seeed Arch Mix NXP i.MX RT1052 Board” I explained how to take complete control over the board and flash and debug a firmware. Of course this overwrites the one which comes by default shipped on the board. This article is about how to restore or update the original firmware.
Restored Seeed Firmware
In my previous article “Seeed Studio Arch Mix NXP i.MX RT1052 Board” I described how I can use and debug the Seeed Arch Mix Board. But so far I only had things running in RAM. Ultimately I want to use the QSPI FLASH memory on the device with my firmware and running code on it. This article shows how to get from RAM execution to SPI FLASH in-place execution (XiP).
Seeed Arch Mix NXP i.MX RT1052 Board
The Seeed Studio ‘Arch Mix’ board is a small and versatile development board with an NXP i.MX RT1052 on it, and it costs only $29.90. So I was not able to resist and just have ordered one so I can explore it.
Seeed Arch Mix Top Side
By default, Eclipse provides ‘stop-mode-debugging’: in order to inspect the target code and data, I have to stop the target. But with the right extensions as present in the Eclipse based MCUXpresso IDE, it is possible to inspect the target even while it is running.
Graphing Variables
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
A few days ago NXP has released a new version of their Eclipse IDE flagship: the MCUXpresso IDE v11.0.
NXP MCUXpresso IDE V11.0.0
The previous v10.3.1 was released back in Feb 2019, and the 11.0 now in June this year matches up with the Fall university semester. I appreciate that the releases are about every 6 months, so this gives me time to use it in my university lecture material and lab work. I had the weekend for trying it out, and I’m very pleased.
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
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
