W65C832_1 Datasheet, PDF (12/64 Pages) –

WDC
THE WESTERN DESIGN CENTER, INC.
W65C832
1.10 Program Bank Register (PBR)
The 8-bit Program Bank Register holds the bank address for all instruction fetches.
The 24-bit address consists of the 16-bit instruction effective address and the
8-bit Program Bank address. The register value is multiplexed with the data value
and presented on the Data/Address lines during the first half of a program memory
read cycle. The Program Bank Register is initialized to zero during Reset. The PHK
instruction pushes the PBR register onto the Stack.
1.11 Program Counter (PC)
The 16-bit Program Counter Register provides the addresses which are used to step
the microprocessor through sequential program instructions. The register is
incremented each time an instruction or operand is fetched from program memory.
1.12 Stack Pointer (S)
The Stack Pointer is a 16-bit register which is used to indicate the next available
location in the stack memory area. It serves as the effective address in stack
addressing modes as well as subroutine and interrupt processing. The Stack Pointer
allows simple implementation of nested subroutines and multiple-level interrupts.
During the Emulation mode, the Stack Pointer high-order byte (SH) is always equal to
one. The bank address for all stack operations is Bank zero.
MARCH 1990
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