The first STM8 microcontrollers were released by STMicroelectronics to replace the ST7 family in early 2008. At the same time, a sixfold increase in productivity was declared compared to the previous family. The main emphasis was placed on crystals high reliability and their protection from static voltage. This meant they were used in the automotive industry mostly and in the cases required high reliability with low power consumption. Somewhere in the middle of 2010, these controllers appeared on a wide sale, and attracted our attention by the price, a wide range and completely unrealistic prices for Atmel products. Let's take a closer look at  STMicroelectronics offer.
General overview of architecture.
The core is built according to the Harvard architecture when the address space of commands and data are divided, but this division is internal. For the programmer, it is a  von Neumann  processor that allows you to use a single address space. Maximum core frequency - up to 24 MHz for older models

- from 4 to 128 KB, SRAM size - from 1 to 6 KB.
The core and periphery of the microcontroller operate on 1.8 V supply voltage, the power supply of a controller depends on its series. The STM8 family is divided into three subfamilies:
- STM8L is a family of low power microcontrollers for battery powered devices. Supply voltage ranges from 1.65 to 3.6 V.
- STM8S - general purpose microcontrollers. Supply voltage ranges from 2.95 to 5.5 V.
- STM8A - highly reliable microcontrollers.

STM8L Series

STM8AL Series

STM8AF Series