SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 68

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

4.4
The time to execute an instruction depends primarily on where the instruction is fetched
from, and where the possible operands are read from or written to. The fastest
processing mode of the C164CM is execution of a program fetched from the internal
code memory. In this case, most of the instructions can be processed within just one
machine cycle, which is also the general minimum execution time.
All external memory accesses are performed by the C164CM’s on-chip External Bus
Controller (EBC), which works in parallel with the CPU.
This section provides a very condensed summary of the execution times. A detailed
description of the execution times for the various instructions and the specific exceptions
can be found in the “C166 Family Instruction Set Manual”.
Table 4-1
instruction fetched from the internal code memory, the internal RAM, or from external
memory. These execution times apply to most of the C164CM instructions - except for
some of the branches, the multiplication, the division, and a special move instruction. In
case of internal ROM program execution, there is no execution time dependency on the
instruction length except for some special branch situations. The numbers in the table
are in units of CPU clock cycles and assume no waitstates.
Table 4-1
Memory Area
Internal code memory
Internal RAM
16-bit Demux Bus
16-bit Mux Bus
8-bit Demux Bus
8-bit Mux Bus
Execution from the internal RAM provides flexibility in terms of loadable and modifyable
code on the account of execution time.
Execution from external memory is heavily dependent on the selected bus mode and the
programming of the bus cycles (waitstates).
User’s Manual
shows the minimum execution times required to process a C164CM
Instruction State Times
Minimum Execution Times
Instruction
Word
Instruction Fetch
2
6
2
3
4
6
4-11
Doubleword
Instruction
12
2
8
4
6
8
Central Processing Unit (CPU)
Read from
Word Operand Access
0/1
2
2
3
4
6
C164CM/C164SM
Derivatives
V1.0, 2002-02
Write to
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0
2
3
4
6