Programming

STM32 Minimal Development Environment

Tags: ARM, Embedded, Programming

In the past I have written on the advantages of minimal development environments (read: Makefiles and GCC, no IDE, minimal abstraction layers) for ARM processors. One of the advantages of working this way is easy integration with existing processes such as build systems, production line, testing, etc. Using this in a virtualized environment also allows one to make sure every developer uses the same tools, and that the tools are tested and qualified for the intended project with a ready made virtual image available for each developer. They can then add their favorite editor and user interface, but the underlying build environment is fixed for everyone and archived as such on a per-project basis. This means that if a customer comes back a year or two later and wants to make a change, all the tools are there as we left them ready to make the change. In this blog post I'll write down a possible scenario for a typical STM32 project, in this case using a NUCLEO-L152RE board as a target. It should be easy to adapt to other STM32 boards/chips, and in general other ARM microcontrollers as well.

Programmer on chair

Some Thoughts on Securing IoT Devices

Tags: Cryptography, Embedded, Programming, Security

Security in the Internet of Things (IoT) leaves much to be desired. Some of the recent DDoS attacks such as those through Mirai on DNS provider Dyn or on popular security site KrebsonSecurity have been possible due to weak security measures in things like network connected cameras. There are many reasons why the situation is what it is today, but that will not be the topic of this entry. While we have seen some initiatives, notably the security guidelines (PDF) by NIST and some comments made by Bruce Schneier, I feel that this leaves a lot of people wondering what practical measures to take to secure their devices. Many companies in the IoT are start-ups lacking a proper understanding of what security in the embedded field entails, and might lack (or didn't plan for) the budget to hire dedicated security people. The goal of this blog entry are to (hopefully) lift the veil on some of the methodologies that should be employed to create more secure IoT systems from a very practical point of view.

IOT

Standard Peripherals Library vs CMSIS vs HAL vs Low Level Library

Tags: ARM, C, Electronics, Embedded, Programming

The STM32 line of microcontrollers offer a bunch of features in a nice package at reasonable cost, something I like. What I don't like as much are the development libraries around it provided by ST. For this reason, most of the time I stick to writing code using the 'Cortex Microcontroller Software Interface Standard' (CMSIS) and the datasheet, and this works nicely but can be slow to develop. While it's still my personal favorite, I recently checked out the other options to see where things are going to do the prep work for some ports of older projects built using the 'Standard Peripherals Library' to newer processors such as the STM32L4.

 

Microcontroller

 

Anyone Can Code...

Tags: Other, Programming

Every time I hear the "everybody can/should/has to code" line...

Anyone Can Code

Flashing STM32L15X EEPROM with STLink under Linux

Tags: Embedded, Linux, Programming

For a while now I've been evaluating some 32-bit micro controllers for a future product. One of them was the STM32L15x series. There are some handy development boards available such as the Nucleo boards. Since we need to have the ability to program processors from Linux for our small production line, tool support is one of the checkboxes that need to be ticked.

For the STM32 series, flashing the microcontroller can be done through GDB, OpenOCD, and the STLink tool. One issue that arose however was the need to program the EEPROM available on the STM32L series. This requirement comes from need to generate and program different EEPROM content on a per board basis at the production line. Doing that requires a few tweaks that are documented below...

Solutions