The Longan Nano is a new contestor in the area of affordable RISC-V development boards. The Longan Nano’s form factor and price puts it up against the Arduino Nano and all other varieties of STM32-based “nano boards”, which can be found abundantly on Ebay and AliExpress.
In the past I used USBtiny and USBasp programmers to flash Atmel microcontrollers. Under Windows 10 the programmers did not work, even though Windows 10 seemed to detect them correctly.
It turns out Windows 10 does not use/fetch the correct drivers.
To make things work again most folk use Zadig a tool which automatically installs some legacy drivers typically used for USB programmer dongles.
After the drivers are installed Windows 10 finally detects my USBasp programmer dongle as it should.
When tasked with the implementation of a rather complex function, e.g. a polynomial of higher order, the resource utilization quickly shoots through the roof if implemented straight forward (also called the naïve implementation).
To avoid this it is often easier, simpler and faster to use a lookup table (LUT) solution.
For the STM32 family of microcontrollers a number of different support libaries are available: Cortex Microcontroller Software Interface Standard (CMSIS), Standard Peripheral Library (SPL), Hardware Abstraction Layer (HAL).
Unfortunately Windows 10 does not accept the standard drivers for the USBasp programmer. The reason is that the drivers have no valid signature from Microsoft (as required by Windows 10).
The only way around this problem seems to be to temporarily disable signature checking and then install the drivers (if you are fine with the security risk). This is described in detail here.