Datasheet

C161S
Functional Description
Data Sheet 14 V1.0, 2003-11
A system stack of up to 1024 words is provided as a storage for temporary data. The
system stack is allocated in the on-chip RAM area, and it is accessed by the CPU via the
stack pointer (SP) register. Two separate SFRs, STKOV and STKUN, are implicitly
compared against the stack pointer value upon each stack access for the detection of a
stack overflow or underflow.
The high performance offered by the hardware implementation of the CPU can efficiently
be utilized by a programmer via the highly efficient C161S instruction set which includes
the following instruction classes:
• Arithmetic Instructions
• Logical Instructions
• Boolean Bit Manipulation Instructions
• Compare and Loop Control Instructions
• Shift and Rotate Instructions
• Prioritize Instruction
• Data Movement Instructions
• System Stack Instructions
• Jump and Call Instructions
• Return Instructions
• System Control Instructions
• Miscellaneous Instructions
The basic instruction length is either 2 or 4 bytes. Possible operand types are bits, bytes
and words. A variety of direct, indirect or immediate addressing modes are provided to
specify the required operands.