The HD64180 is a
Z80
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...
-based embedded
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...
developed by
Hitachi with an integrated
memory management unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit having all memory references passed through itself, primarily performing the translation of virtual memory addresses to physical a ...
(MMU) and on-chip peripherals. It appeared in 1985. The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the
Zilog Z180
The Zilog Z180 eight-bit processor is a successor of the Z80 CPU. It is compatible with the large base of software written for the Z80. The Z180 family adds higher performance and integrated peripheral functions like clock generator, 16-bit coun ...
.
Overview
The HD64180 has the following features:
* Execution and bus access clock rates up to 10 MHz.
* Memory Management Unit supporting 512K bytes of memory (one megabyte for the HD64180 packaged in a PLCC)
* I/O space of 64K addresses
* 12 new instructions including 8 bit by 8 bit integer multiply, non-destructive AND and illegal instruction trap vector
* Two channel
Direct Memory Access
Direct memory access (DMA) is a feature of computer systems and allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU).
Without DMA, when the CPU is using programmed input/output, it is ...
Controller (DMAC)
* Programmable wait state generator
* Programmable
DRAM refresh
* Two channel Asynchronous Serial Communication Interface (ASCI)
* Two channel 16-bit Programmable Reload Timer (PRT)
* 1-channel Clocked Serial I/O Port (CSI/O)
* Programmable Vectored Interrupt Controller
The HD64180 has a pipelined execution unit which processes most instructions in fewer clock cycles than the
Z80
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...
. The most improved instruction group comprises the block instructions; for example those such as LDIR, CPIR, INIR and OTDR. This instruction type takes 21 transition states to execute per iteration; on the HD64180 it takes 14 t-states.
The on-chip DMAC makes block memory transfers possible at a rate faster than the LDIR/LDDR instructions. The on-chip generator for wait states makes it possible to access too-slow hardware on a selective basis using a device filter, as is done for the
TRS-80 Model 4
The TRS-80 Model 4 is the last Z80-based home computer family by Radio Shack
RadioShack, formerly RadioShack Corporation, is an American retailer founded in 1921.
At its peak in 1999, RadioShack operated over 8,000 worldwide stores named Rad ...
's balky keyboard. The on-chip ASCI makes it possible to implement additional RS-232 serial ports.
The HD64180 will not execute the "undocumented" Z80 instructions, particularly the ones that access the index registers IX and IY as 8-bit halves. The Hitachi CPU treats them as illegal instructions and accordingly executes the illegal instruction trap, redirecting the PC register to address zero.
The Micromint SB180, SemiDisk Systems DT42
CP/M computers, and Olivetti CWP 1 and ETV 210s videotypewriters (also running ROM based CP/M 2.2) were based on the Hitachi HD64180. The XLR8er upgrade board for the
TRS-80 Model 4
The TRS-80 Model 4 is the last Z80-based home computer family by Radio Shack
RadioShack, formerly RadioShack Corporation, is an American retailer founded in 1921.
At its peak in 1999, RadioShack operated over 8,000 worldwide stores named Rad ...
also used it. On the Victor HC-90 and HC-95
MSX2
MSX is a standardized home computer architecture, announced by Microsoft and ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, then vice- ...
computer, the HD64B180 was used for its turbo mode next to the regular Z80.
See also
*
Zilog Z180
The Zilog Z180 eight-bit processor is a successor of the Z80 CPU. It is compatible with the large base of software written for the Z80. The Z180 family adds higher performance and integrated peripheral functions like clock generator, 16-bit coun ...
References
Further reading
External links
HD64180 High Integration CMOS Microcontrollers Family DatasheetHD64180 8-Bit High Integration CMOS Microprocessor User ManualHD64180 8-Bit High Integration CMOS Microprocessor Data BookArthur-PC, homemade HD64180 based computer
Hitachi products
Embedded microprocessors
8-bit microprocessors
{{compu-hardware-stub