Viewing ARM CPU activity in real time


Jeremy Bentham writes:

In previous blog posts, I have described how an FTDI USB device can be programmed in Python to access the SWD bus of an ARM microprocessor. This allows the internals of the CPU to be accessed, without disrupting the currently running program.
In this blog I take the process one step further, and add a graphical front-end, that shows the CPU activity in real time

More details on Iosoft blog. Source files are available on GitHub.

Regaining debug access of NXP i.MX RT1064-EVK executing WFI


Erich Styger writes:

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.

More details on MCU on Eclipse blog.

The ARM chip that wont cost an arm and a leg

2018-09-18T16 25 43.036Z-board

A small ARM developmentboard from SMDprutser, that is available on GitHub:

Searching the prerequisite Chinese websites to satisfy my shopping fetish I came across a neat little ARM Cortex-M0 chip which is an extremely good bang for buck. I believe it is the smallest chip available in a reasonable hand-solderable package (TSOP8). This board gives you everything to explore this marvel of this Chinese Semiconductor.

Project info at It’s also up on Tindie.

Building a USB bootloader for an STM32


Kevin Cuzner writes:

As my final installment for the posts about my LED Wristwatch project I wanted to write about the self-programming bootloader I made for an STM32L052 and describe how it works. So far it has shown itself to be fairly robust and I haven’t had to get out my STLink to reprogram the watch for quite some time.
The main object of this bootloader is to facilitate reprogramming of the device without requiring a external programmer.

More details on Projects & Libraries’ homepage.

STM32F103 vs GD32F103 round 4: SPI master


Sjaak writes, “This is part 4 in the series where we compare the STM32F103 with its Chinese counterpart the GD32F103. Both are ARM Cortex M3 microcontrollers which are mostly pin, peripheral and register compatible. Now we compare the SPI master peripheral of both chips.”

More details at

Check out the video after the break. 

LoRa module in DIL form


Mare writes:

Murata produces LoRa module CMWX1ZZABZ-xxx based on SX1276 transceiver and STM32L072CZ microcontroller. The soldering of the LGA module is not very hobby-friendly. I constructed small breakout PCB for this module with additional buck/boost switcher and place for SMA connector. The transceiver features the LoRa®long-range modem, providing ultra-long-range spread spectrum communication and high interference immunity, minimizing current consumption. Since CMWX1ZZABZ-091 is an “open” module, it is possible to access all STM32L072 peripherals such as ADC, 16-bit timer, LP-UART, I2C, SPI and USB 2.0 FS (supporting BCD and LPM), which are not used internally by SX1276.

More details on Mare & Gal Electronics site. Project files are available at Github.

STM32F103 vs GD32F103 round 3: UART


Here’s the part 3 of Sjaak’s post comparing the GD32 to the STM32:

Since the GD32F103 can run as fast as 108MHz but has not a proper USB clock divider to provide a 48MHz clock for USB communication we need another way to communicate with the outside world. Since the early days of computing the easiest way to go is a asynchronous serial interface using the UART peripheral. I can try to explain how this protocol works, but here is a better write-up.

If you missed part 1 and part 2, be sure to check it out.

More info at

STM32F103 vs GD32F103 round 2: Blink a LED


A follow-up to the STM32F103 vs GD32F103 round 1- Solderability post, Sjaak writes:

The defacto ‘hello world’ for microcontrollers is blink a LED at a steady rate. This is exactly what I’m going to do today. I made a small 5×5 development board, soldered it up and started programming. In this first example we not gonna use fancy IRQs or timers to blink at a steady rate, but we insert NOPsas delay. This would give an idea of the RAW performance of the chip. The used code is simple; set up the maximum available clock available and then toggle RA0 for ever.

More details at

STM32F103 vs GD32F103 round 1: Solderability


Sjaak writes:

I locked myself into the basement with a couple of PCBs, chips and fresh flux for a couple of days. For the STM32F103 vs GD32F103 challenge I needed to have two identical boards with a different microcontroller. As far as I could judge both chips are legit and not counterfeits as we bought both chips from (different) reputable sellers. The used chips are GD32F103CBT6 and STm32F103CBT7. The STM32F103CBT7 is the industrial rated part of the STM32F103CBT6 and is identical except for the temperature range.

More details at

STM8 Microcontrollers


Here’s a three-part series of posts by Shawon Shahryiar detailing the STM8 microcontrollers:

STM8 microcontrollers are 8-bit general purpose microcontrollers from STMicroelectronics (STM). STM is famous mainly for its line of 32-bit ARM Cortex microcontrollers – the STM32s. STM8 microcontrollers are rarely discussed in that context. However, STM8 MCUs are robust and most importantly they come packed with lots of hardware features. Except for the ARM core, 32-bit architecture, performance and some minor differences, STM8s have many peripheral similarities with STM32s.

Read the full post at Embedded Lab’s blogPart 1 and Part 2 are also available.

Check out the video after the break.