dmp (12/03/82)
I am looking for any information, books or personal experience with the ZX81 computer. (Also any information on the Timex sinclair 1000, assuming there are almost identical machines.) Preferably information or documentation on: 1) The hardware characteristics: a) keyboard scanning b) load and save machine level operation c) I/O port addresses(ing) 2) Info on the ROM (monitor - operating system): a) a dissasembly (hopefully !!!!) b) use of ROM subroutines c) *-> any INFO <-* 3) Any info that would make it possible to better understand the the Z80A's machine level programming particular to the ZX81 or Sinclair. I have been searching book stores, and my associate workers minds for readily available info, (with little luck). Any pointers or info will be greatly appreciated. Please send mail or call Thanx in advance. Dave Plaisted (ariel!dmp) Bell Laboratories Holmdel, NJ 201-949-4437
schwager (12/05/82)
#R:ariel:-14600:uiucdcs:10500010:000:1319 uiucdcs!schwager Dec 5 00:11:00 1982 If you dont mind going mailorder, try the back of Computer Electronics or Radio-Electronics for ads of places selling ZX-81 stuff. I have a catalog from Gladstone Electronics and they might have some books covering some of the info you're looking for. I know there are two volumes out that give a complete disassembly of the 8k ROM: "zx81 ROM Disassembly, Part A" and "zx81 ROM Disassembly, Part B", by Dr. Logan (whoever he is). Part A covers 000H to 0F54H (this excludes the floating point calculator). Part B covers 0F55H to 1DFFH (includes all routines used in the floating point calculator). They have another book, "The Explorers Guide to the zx81" that looks like it carries a lot of general info. The description says it covers programming aids for BASIC, some macihine language topics. Also, "ROM routines, ROM tables, load & save instructions, display file info, and keyboard scanning are all discussed in (sic) The Hardware Chapter gives informationon how to connect an external keyboard, connecting a monitor, hooking up a speaker for listening while saving or loading, and gives circuit diagrams of 1-4k RAM, 24 line I/O, 16k RAM, and more." Hopefully Santa Claus will bring me that book. Send me some mail after Christmas and maybe I will have some more detailed info for you. Hope this helps.
will@sri-unix (12/07/82)
Concerning the earlier reply to this: Dr. Ian Logan is kindof #2 in the Sinclair Industry, although he has no connection with the company. He seems to know as much about the machines as Uncle Clive (or was it Clide?) himself. He writes regularly for SYNC and others. On the other hand, what do we care? The Explorers Guide to the ZX81 is supposed to be excellent. It gives not only pointers on programming, but programming style and how to effectively use machine code. Also, 'Mastering Machine Code on your ZX81' is also supposed to be good, taking people from BASIC to machine code. Will D.