During Embedded World 2017 in Nürnberg I was lucky to get a handful LPC800-DIP boards. To get all students who were lucky to get one, here is a tutorial to make that very exciting ‘blinky’ application on that board:
Blinky on the NXP LPC800-DIP
The MCUXpresso IDE (see “MCUXpresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers“) has one great feature: it includes debug support for the popular LPC-Link2 debug probes. That way I have yet another powerful debug probe with extra features for ARM based boards. That LPC-Link2 circuit is present on many LPCXpresso boards from NXP. So why not using it to debug it my custom hardware?
Debugging Custom Hardware with LPCXpresso Board
I believe in ‘life-long-learning’. With this I continue to learn and discover new things every day. I’m writing tutorials to give something back to the community from which I have learned so much.
On top of this, I receive emails on a nearly daily basis, asking for help. Many articles have the origin in such requests or questions. I prefer questions or comments in a public forum, because that way I feel all others can benefit from it. Last week Alessandro contacted me with this:
“Hi Erich,
I hope this find you well! I’m starting to using ARM processors, but I find them quite complicated on the configuration side. I started in the past with PIC micro (PIC16) with asm, and I found them quite straightforward to be configured (clock, IO, peripherals, …). Then I moved myself on C language, and on PIC18 without any big issues.
Now I would really like join the ARM community, I see that these processors are what I’ve always looking for, on energy, calc power, peripherals, and FINALLY on IDE (editor, toolchain and utilities)… AMAZING!!!”
The topic is about how to start learning developing for ARM. Alessandro agreed to make this public, so I thought this might be a good topic for an article?
Firmware
Looking for a small, inexpensive ($25-30) ARM development board (say 120-180 MHz ARM Cortex-M4 with FPU, 512kB-1MB of FLASH and 256 KByte of RAM? Then have a look at the Teensy 3.5 and Teensy 3.6 by PJRC/Paul Stoffregen:
Teensy 3.5 with NXP K64F ARM Cortex-M4F
The only problem? it is not possible to debug it :-(. At least not in the traditional sense. This article is about how to change the board to use it with any normal SWD debugging tool e.g. Eclipse and the Segger J-Link :-).
In “Tutorial: Secure TLS Communication with MQTT using mbedTLS on top of lwip” I already used TLS for a secure communication, but I had not enabled server certificate verification. This article is about closing that gap.
Secure MQTT running on NXP FRDM-K64F with lwip and mbed TLS
One of the most important aspects of the ‘IoT’ world is having a secure communication. Running MQTT on lwip (see “MQTT with lwip and NXP FRDM-K64F Board“) is no exception. Despite of the popularity of MQTT and lwip, I have not been able to find an example using a secure TLS connection over raw/native lwip TCP :-(. Could it be that such an example exists, and I have not found it? Or that someone implemented it, but has not published it? Only what I have found on the internet are many others asking for the same kind of thing “running MQTT on lwip with TLS”, but there was no answer? So I have to answer my question, which seems to be a good thing anyway: I can learn new things the hard way :-).
Block diagram MQTT Application with TLS using lwip
In the area of IoT (Internet of Things), one obvious need is to have a way to send and receive data with an internet protocol. MQTT (or Message Queue Telemetry Transport) is exactly like that: a light-weight Machine-to-Machine communication protocol. With the MQTT protocol a microcontroller (or ‘client’) can send data and/or subscribe to data. For example to the Adafruit.IO:
Adafruit MQTT IO Feed
For me, the available software and tools are the primary key decision factor why I select a particular silicon vendor. Without good software and tools, a microcontroller only ‘sand in plastic case’, even if it is the best microcontroller in the world. I do have several probably excellent microcontroller boards, and they are only getting touched by more durst over the months and years.
Undusted LPC824 Board
There are many mergers going on in the industry, and one of the largest one was in 2016 the integration of Freescale Semiconductor with NXP Semiconductors, with both providing Eclipse based IDE’s to their customer base. Consequently, the company merger triggered a merger of the IDE’s, and last week NXP has released the result: the MCUXpresso IDE.
MCUXpresso IDE
Space is a hostile environment. Sending hardware to space means putting it under irradiation tests: exposing the object to radiation and see what happens :-). For this, under the lead of the ETHZ (Mathematical and Physical Geodesy), we had the opportunity to put the CubETH payload board under a proton beam. The test facility is at the Paul Scherrer Institute (PSI) in Villigen, Switzerland:
Control Room at PSI
MCU on Eclipse 