CZ80CPU
8-Bit Microprocessor
Megafunction
General Description
Implements a fast, fully-functional, single-chip, 8-
bit microprocessor with the same instruction set
as the Z80.
The core has a 16-bit address bus capable of
directly accessing 64kB of memory space. It has
252 root instructions with the reserved 4 bytes as
prefixes, and accesses an additional 308
instructions.
The microcode-free design was developed for
reuse in ASIC and FPGA implementations. It is
strictly synchronous, with no internal tri-states
and a synchronous reset.
Features
Programming features contain 208 bits of
read/write memory that are accessible to the
programmer. The internal registers include an
accumulator and six 8-bit registers that can be
paired as three 16-bit registers. In addition to
general registers, a 16-bit stack-pointer, 16-bit
program-counter, and two 16-bit index registers
are provided.
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Control Unit
o
8-bit Instruction decoder
Arithmetic-Logic Unit
o
8-bit arithmetic and logical
operations
16-bit arithmetic operations
Boolean manipulations
Symbol
o
o
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Register File Unit
o
o
Duplicate set of both general
purpose and flag registers
Two 16-bit index registers
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Interrupt Controller
o
o
Three modes of maskable interrupts
Non maskable interrupt
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External Memory interface
o
o
o
Can address up to 64 KB of program
memory
Can address up to 64 KB of data
memory
Can address up to 64 KB of
input/output devices
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On-core dynamic memory refresh counter
CAST, Inc.
April 2004
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