User’s Manual
C166S V1 SubSystem
System Overview
User’s Manual
2-7
V 1.6, 2001-08
2.2
The C166S System Resources
The C166S based subsystem provides a number of powerful system resources
designed around the CPU. The combination of CPU and these resources results in the
high performance of the members of this controller family.
2.2.1
Memory Areas
The memory space of the C166S is configured in a Von Neumann architecture which
means that code memory, data memory, registers and I/O ports are organized within the
same linear address space which covers up to 16 MBytes. The entire memory space can
be accessed bytewise or wordwise. Particular portions of the on-chip memory have
additionally been made directly bit addressable.
An up to 3 KByte 16-bit wide internal DPRAM provides fast access to General
Purpose Registers (GPRs), user data (variables) and system stack. The DPRAM may
also be used for code. A unique decoding scheme provides flexible user register banks
in the internal memory while optimizing the remaining RAM for user data.
The CPU has an actual register context consisting of up to 16 wordwide and/or bytewide
GPRs at its disposal, which are physically located within the on-chip RAM area. A
Context Pointer (CP) register determines the base address of the active register bank to
be accessed by the CPU at a time. The number of register banks is only restricted by the
available DPRAM space. For easy parameter passing, a register bank may overlap
others.
A system stack is provided as a storage for temporary data. The system stack is also
located within the on-chip RAM area, and it is accessed by the CPU via the stack pointer
(SP) register. Two separate SFRs, STacK OVerflow (STKOV) and STacK UNderflow
(STKUN), are implicitly compared against the stack pointer value upon each stack
access for the detection of a stack overflow or underflow.
Hardware detection of the selected memory space is placed at the internal memory
decoders and allows the user to specify any address directly or indirectly and obtain the
desired data without using temporary registers or special instructions.
For Special Function Registers 1024 Bytes of the address space are reserved. The
standard Special Function Register area (SFR) uses 512 bytes, while the Extended
Special Function Register area (ESFR) uses the other 512 bytes. (E)SFRs are wordwide
registers which are used for controlling and monitoring functions of the different on-chip
units. Unused (E)SFR addresses are reserved for future members of the C166 family
with enhanced functionality.
An optional Local Memory is provided for both code and data storage. This memory
area is connected to the CPU via a 32-bit-wide local memory bus. Program execution
from Local Memory is the fastest of all possible alternatives.
The type of the on-chip Local Memory (Flash/ROM/SRAM/DRAM/none) depends on the
chosen derivative.
Содержание C166S V1 SubSystem
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Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
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