In JTAG Debugging the ESP32 with FT2232 and OpenOCD I have used a FTDI FT2232 breakout board to JTAG debug with OpenOCD. With an adapter board on top of the TDI FT2232 the wiring is much easier and simpler to use:
JTAG Debugging the ESP32 with FT2232
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
In “Eclipse JTAG Debugging the ESP32 with a SEGGER J-Link” I used a SEGGER J-Link to debug an ESP32 device with JTAG. I looked at using one of the FTDI FT2232HL development boards which are supported by OpenOCD. The FT2232HL is dual high-speed USB to UART/FIFO device, and similar FTDI devices are used on many boards as UART to USB converters. With OpenOCD these devices can be turned into inexpensive JTAG debug probes. This article shows how to use a $10 FTDI board as JTAG interface to program and debug the Espressif ESP32.
FTDI JTAG Connection
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
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
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
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;
}
}
