On the ESP8266 ESP-01, CH_PD must be pulled HIGH at boot for the chip to work. Some variants of the ESP-01 module do not require this, but it does not hurt to have it so. The connection can be done directly or via a 10K resistor.
Author Archives: E Y
Remember, C# does not have an exponent operator
This is a cautionary tale for developers who switch between programming languages often. Whilst reviewing some logs, I noticed that durations of pauses between API requests were incorrect. They were expected to double on every subsequent attempt, starting from a fixed base interval; for example, 5 seconds, 10 seconds, 20 seconds, 40 seconds, and so …
Continue reading “Remember, C# does not have an exponent operator”
Convert a value from scientific notation to decimal in T-SQL
A VARCHAR value that is in scientific notation can be converted to a DECIMAL value by first converting it to a REAL value, then to the DECIMAL value. For example: This also works with CAST.
Avoiding time drift in virtual machines
If you use a virtual machine, you might have noticed that its system time starts to lag after it has been in the ‘powered on’ state for some time. To address this, it is useful to run an NTP (Network Time Prococol) client within the VM to have its time synchronised regularly. On Windows, this …
Caveat with AddInitialRequestCultureProvider() in ASP.NET Core
AddInitialRequestCultureProvider() in ASP.NET Core localisation seems to have an undefined behaviour when it is used in both services and application builder configurations to add a custom RequestCultureProvider. If you want to use a custom RequestCultureProvider to customise how the applicable culture is determined for an incoming HTTP request (for example, by looking up the chosen …
Continue reading “Caveat with AddInitialRequestCultureProvider() in ASP.NET Core”
How can you minimize the impact of the persistence layer on your domain models?
This is a blog response to the question ‘How can you minimize the impact of the persistence layer on your domain models?’ posted on reddit /r/dotnet, showing how I would have implemented the solution in the purest form of OOP that is possible with C#. (Note: The implementation of the factory and persistence classes is …
Continue reading “How can you minimize the impact of the persistence layer on your domain models?”
Solving vfprintf.c:(.text.avr-libc+0xc8): undefined reference to ‘__mulqi3’ linking error
If you encounter the above linking error with an ATmega328p and your code uses sprintf, set your LIBRARY_PATH or the linker argument -L to /usr/lib/avr/lib/avr5 instead of /usr/lib/avr/lib.
.vimrc
rg.exe is part of ripgrep.
Disabling Bluetooth auto-suspend with module options
In my previous post I showed how to restart Bluetooth on Debian Linux. Here I explain how to disable Bluetooth auto-suspend by using a kernel module option. Kernel modules can be passed parameters that affect how they work. The parameters accepted by a module can be identified with the command modinfo. In the example below …
Continue reading “Disabling Bluetooth auto-suspend with module options”
Restarting Bluetooth on Debian Linux
On my laptop I use a Bluetooth keyboard and a Bluetooth mouse. Occasionally the Bluetooth adapter in the laptop shuts off completely, which means that it is not even possible to restart the Bluetooth service with sudo systemctl restart bluetooth.service. My troubleshooting points to powersaving as the cause of this, but the TLP setting that …