Tag Archives: Tips&Tricks

About things you might not know, or could make your life easier.

“No source available”, or how to Debug Multiple Binaries with GDB and Eclipse

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When working and debugging a bootloader, debugging can be a challenge: During debugging the bootloader, a new binary gets loaded into the microcontroller address space which is unknown to the debugger. As soon as I step into the newly loaded binary, I only see assembly code, with that ugly “No source available” in Eclipse:

No Source Available, debugging in assembly

No Source Available, debugging in assembly

But wait: GDB is able to do pretty much everything you can imagine, so here is how to debug multiple binaries with GDB and Eclipse, and to turn the above into something which is easy to debug:

Debugging with Symbolics

Debugging with Symbolics

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Reprogramming the Mikroelektronika Hexiwear Dockingstation

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The Hexiwear docking station would have a nice feature: it has embedded a debug circuit (OpenSDA). That way I would not need an external debug probe to debug the Hexiwear. However, a debug probe is required to reprogram the docking station itself:

Repgrogramming the Mikroelektronika Docking Station

Repgrogramming the Mikroelektronika Docking Station

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Debugging ARM Cortex-M0+ HardFaults

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To me, one of the most frustrating things working with ARM Cortex-M cores are the hard fault exceptions. I have lost several hours this week debugging and tracking an instance of a hard fault on an ARM Cortex-M0+ device.

Next assembly step will cause a hard fault
Next assembly step will cause a hard fault
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Building the NXP BLE Stack with Open Source GNU and Eclipse Tools

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One of the biggest road blocks (beside of closed source) using the BLE (Bluetooth Low Energy) stack from NXP is that it requires expensive tools to compile and build the stack. The good news is that I have now the NXP BLE stack for the Mikroelektronika Hexiwear ported to Eclipse and GNU gcc build tools for ARM 🙂

NXP BLE Stack in Eclipse

NXP BLE Stack in Eclipse

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Using Python, Gatttool and Bluetooth Low Energy with Hexiwear

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Now I can use the data on the Hexiwear over BLE with the gatttool (see “Tutorial: Hexiwear Bluetooth Low Energy Packet Sniffing with Wireshark” and “Tutorial: BLE Pairing the Raspberry Pi 3 Model B with Hexiwear“). This article is taking things a step further and uses a Python script on Linux to access the sensor data on the BLE device:

Accessing Hexiwear Sensor Data with Python

Accessing Hexiwear Sensor Data with Python

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DIY IKEA Wireless Qi Charging for the Hexiwear

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The Achilles Heel of the Mikroelektronika Hexiwear is its charging: the charging and USB connector are only designed for a limited number of plug-unplug cycles, and it does not have a wireless charging capability like the Apple iWatch. Until now! I have built a DIY wireless charging system for the Hexiwear 🙂 :

Wireless Qi Charging the Hexiwear

Wireless Qi Charging the Hexiwear

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VNC Server on Raspberry Pi with Autostart

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The Raspberry Pi is a versatile mini computer: as such I can use it with USB keyboard, mouse and HDMI LCD monitor. But having multiple keyboards and mouse on my desktop is not my thing: somehow I always grab the wrong one. So what I prefer is to run the Raspberry with VNC (Virtual Network Computing). That way I have the Linux GUI as a window on my normal desktop, and no messing up with keyboards and mouse 🙂 :

Raspberry Pi on my Dekstop

Raspberry Pi on my Dekstop

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Hexiwear with Raspberry Pi and OpenHAB Home Automation

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This is yet another milestone on my journey to combine the Hexiwear with the Raspberry Pi: now I can send take over control of the Hexiwear with openHAB running on the Raspberry Pi:

Controlling Hexiwear with OpenHAB

Controlling Hexiwear with openHAB

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Tutorial: Hexiwear Bluetooth Low Energy Packet Sniffing with Wireshark

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For a university reasearch project I try to pair the Raspberry Pi 3 with a Mikroelektronika Hexiwear using BLE (Bluetooth Low Energy). Most of things worked after a lot of trial and error, but at a certain point I was stuck trying to write to send data from the Raspy to the BLE device.The Hexiwear BLE protocol description is very thin, so I ended up using a BLE sniffer to reverse engineer the protocol with Wireshark.

Sniffing BLE Packets between Raspy and Hexiwear

Hardware setup between Raspy and Hexiwear

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Disabling EzPort on NXP Kinetis to Solve Power-On Issues

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I’m using the NXP FRDM-K64F board in several projects: it is reasonably prices, has USB, Ethernet, micro SD card socket and connectors for Bluetooth classic and Nordic Semiconductor nRF24L01+ 2.4 GHz transceiver:

NXP FRDM-K64F Board

NXP FRDM-K64F Board

But one issue I have faced several times is that the board works fine while debugging and connected and powered by a host machine, but does not startup sometimes if powered by a battery or started without a debugger attached. I have found that the EzPort on the microcontroller is causing startup issues.

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