AN2645 datasheet(22/36 Pages) STMICROELECTRONICS

Part #	AN2645

Description	Migration and compatibility guidelines for STM8S microcontroller applications

PDF	36 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

22 / 36 page

Block-by-block compatibility analysis

AN2645

22/36

3.1.6

Alternate functions and package pinout

The main purpose of the alternate feature concept is to keep the microcontroller

configurable for different user and application needs. This is especially important and useful

in low pin-count packages.

Default alternate functions can be enabled on dedicated pins by settings in the peripheral

registers. A large number alternate functions can be remapped to other pins by

programming the option bytes in data EEPROM memory. So many functions that would

otherwise be lost by migrating to a smaller package size are preserved by remapping

alternate functions to the remaining pins.

The pin layout remapping is controlled by setting the AFRi bits in option byte OPT2. There

are differences in the settings between STM8S sub-families. In the STM8S103x sub-family

there are even differences in the settings between the pin-counts used. In this sub-family

some AFR bits have different meanings for "K" and "F" packages. Refer to the relevant

datasheet to check the correct control and all the differences.

AN2645 Datasheet(PDF) 22 Page - STMicroelectronics