C164CM_2 Datasheet, PDF (58/470 Pages) Infineon Technologies AG – 16-Bit Single-Chip Microcontroller

C164CM/C164SM
Derivatives
Central Processing Unit (CPU)
4
Central Processing Unit (CPU)
Basic tasks of the Central Processing Unit (CPU) are to fetch and decode instructions,
to supply operands for the Arithmetic and Logic unit (ALU), to perform operations on
these operands in the ALU, and to store the previously calculated results. As the CPU is
the main engine of the C164CM microcontroller, it is also affected by certain actions of
the peripheral subsystem.
Because a four stage pipeline is implemented in the C164CM, up to four instructions can
be processed in parallel. Most instructions of the C164CM are executed in one machine
cycle (2 CPU clock periods) due to this parallelism.
This chapter describes how the pipeline works for sequential and branch instructions in
general, and the hardware provisions which have been made to speed up execution of
jump instructions in particular. General instruction timing is described including standard
and exceptional timing.
While internal memory accesses are normally performed by the CPU itself, external
peripheral or memory accesses are performed by a particular on-chip External Bus
Controller (EBC) which is invoked automatically by the CPU whenever a code or data
address refers to the external address space.
Figure 4-1 CPU Block Diagram
User’s Manual
4-1
V1.0, 2002-02