Xilinx CAST CZ80CPU - Manual

October 2012
CZ80CPU
8-Bit Microprocessor
Core
The CZ80CPU 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 implementa-
tions. It is strictly synchronous, with no internal tri-states and a synchronous reset.
Applications
The CZ80CPU is suitable for many embedded controller applications, including:
• industrial control systems
• point-of-sale terminals
• automotive controls
Block Diagram
 Programming features contain
208 bits of read/write memory
that are accessible to the pro-
grammer.
 The internal registers include an
accumulator and six 8-bit regis-
ters 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.
 Control Unit
o
8-bit Instruction decoder
 Arithmetic-Logic Unit
o
8-bit arithmetic and logical
operations
o
16-bit arithmetic operations
o
Boolean manipulations
 Register File Unit
o Duplicate set of both general
purpose and flag registers
o Two 16-bit index registers
 Interrupt Controller
o
Three modes of maskable in-
terrupts
o
Non maskable interrupt
 External Memory interface
o
Can address up to 64 KB of
program memory
o
Can address up to 64 KB of
data memory
o
Can address up to 64 KB of
input/output devices
 On-core dynamic memory re-
fresh counter
Benefits
 The core can be used as an
equivalent of the Zilog™ Z80,
which due to its popularity has a
variety of industry certified
software ready to be used
 Easy implementation in SoC
designs targeted to FPGAs or
ASICs
 Guarantees independence from
chip vendors