Heath8080A — Site Map

Page last updated

home   release   support   design   resources   legal   site map




describes the project scope and background


the current release and a set of useful hdos material available for free download


current release


hdos utilities


contact information, host requirements, product release notes and an overview of emulator limitations


contacting the author


macintosh host system requirements


emulator limitations


release notes


emulator design details


system architecture

an overview of the system architecture describing the three major control flows through the software modules


instruction flow


time distribution


macintosh events



describes the variables that affect performance, the measurement of performance, and analyzes the results of a number of benchmark tests


performance variables







defines 'time' in the context of the emulator and describes how timing information is generated and distributed through the emulator


defining time


time creation


processor pacing


time distribution


h8 processing

describes how the 8080a "chip" is "glued" into the emulator architecture: how memory is initialized, how interrupts are scheduled, and how processor speed is managed


processor initialization


interrupt dispatch


8080a emulation

describes the internal operation of the generic 8080a module, and details a few of the more interesting topics: instruction dispatch, i/o interfacing, memory write protection, registers and flags


instruction dispatch


in/out handling


memory write protection


register design


flag handling


i/o package

describes emulator i/o interfacing, both generically and with pam/8 specifics, and details how the 8250 and 8251 chips are emulated




8250 emulation


8251 emulation


pam/8 port handling


pam/8 gui

describes the three main areas of the gui: keypad and keyboard event handling, front-panel led drawing, and sound feedback generation


keypad events


led drawing




h-17 disk system

describes both the physical and emulated h-17 disk systems in detail, with an emphasis on the procedural aspects of the low-level disk driver's use of the h-17 i/o ports to access the disk system


h-17 physical disk format


disk label format


directory format


date format


i/o port operation


emulator internal disk structure


uninitialized disk handling


h-17 driver notes




h-19 terminal

discusses the emulator's implementation of the h-19 terminal in detail, with an emphasis on keyboard mapping, key translation, and output escape sequence processing


h-19 overview


keyboard mapping


h-19 graphics character generation


character pacing


output character processing


cursor display


serial i/o

describes three of the four serial applications: access to the macintosh printer, file transfer to/from the macintosh, and access to the macintosh modem


print page layout


print handler design


file transfer design


modem design


tape i/o

describes the implementation and operation of pam/8 "cassette tape" load and dump


tape file format


tape implementation


operating instructions


provides links to additional technical resources, other heathkit and h8 related sites, and names the individuals who contributed greatly to the successful implementation of the emulator


technical reference material


other heathkit links


credits and contributions


details my copyrights and the copyrights of other project contributors


web site and emulator copyright


pie text editor notices


hug sy: driver notices


heathkit software copyright status

go to top

home   release   support   design   resources   legal   site map