STM8S903K3 STM8S903F3
Product overview
4
Product overview
The following section intends to give an overview of the basic features of the device functional
modules and peripherals.
For more detailed information please refer to the corresponding family reference manual
(RM0016).
4.1
Central processing unit STM8
The 8-bit STM8 core is designed for code efficiency and performance.
It contains 6 internal registers which are directly addressable in each execution context, 20
addressing modes including indexed indirect and relative addressing and 80 instructions.
Architecture and registers
Harvard architecture
•
3-stage pipeline
•
32-bit wide program memory bus - single cycle fetching for most instructions
•
X and Y 16-bit index registers - enabling indexed addressing modes with or without offset
and read-modify-write type data manipulations
•
8-bit accumulator
•
24-bit program counter - 16-Mbyte linear memory space
•
16-bit stack pointer - access to a 64 K-level stack
•
8-bit condition code register - 7 condition flags for the result of the last instruction
•
Addressing
20 addressing modes
•
Indexed indirect addressing mode for look-up tables located anywhere in the address
space
•
Stack pointer relative addressing mode for local variables and parameter passing
•
Instruction set
80 instructions with 2-byte average instruction size
•
Standard data movement and logic/arithmetic functions
•
8-bit by 8-bit multiplication
•
16-bit by 8-bit and 16-bit by 16-bit division
•
Bit manipulation
•
Data transfer between stack and accumulator (push/pop) with direct stack access
•
Data transfer using the X and Y registers or direct memory-to-memory transfers
•
4.2
Single wire interface module (SWIM) and debug module (DM)
The single wire interface module and debug module permits non-intrusive, real-time in-circuit
debugging and fast memory programming.
DocID15590 Rev 8
11/116
STMICROELECTRONICS [ ST ]
