From: nailed_barnacle@junkfree.hotmail.com (barnacle) Newsgroups: alt.folklore.computers Subject: Anyone remember the predecessor to the ZX80? Followup-To: alt.folklore.computers Date: Tue, 03 Nov 1998 22:07:20 GMT Organization: [posted via] Easynet UK Lines: 21 Message-ID: <71nuro$a8v$1@apple.news.easynet.net> NNTP-Posting-Host: nbarnes.easynet.co.uk X-Newsreader: News Xpress 2.01 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.belnet.be!newsgate.cistron.nl!het.net!newsfeed.wirehub.nl!easynet-tele!easynet-apple!egbert Showing my age now...but the first processor I ever used (mid/late 70s?) was a Sinclair MK14...a huge 512 bytes of memory and a processor (8060?) which had no jump instruction. Input and output were through a calculator keys/LED display, but at least it came with a list of the instruction set for the cpu and entry points to the monitor program...I never managed to make it do anything useful! Another one I had later was a Tangerine. I only ever once saw any code published for it, but it was a delightful machine using a Eurobus variant on a rack frame - It used a 6502 which was a lovely chip, and came with a most professionally produced set of manuals, including monitor listings and circuit diagrams. I designed and built video, memory, audio, and co-processor cards for that beast, and ripped off the design several times for real time systems used in broadcasting - remote controls, program timers etc. One of the program timers is still running without a shutdown after ten years... Ah the days of my youth! Barnacle nailed-barnacle.home.ml.org ###### From: ard@p850ug1.demon.co.uk (Tony Duell) Newsgroups: alt.folklore.computers Subject: Re: Anyone remember the predecessor to the ZX80? Date: 4 Nov 1998 20:56:27 -0000 Organization: P850 User Group Message-ID: <71qf1r$pc@p850ug1.demon.co.uk> References: <71nuro$a8v$1@apple.news.easynet.net> NNTP-Posting-Host: p850ug1.demon.co.uk X-NNTP-Posting-Host: p850ug1.demon.co.uk:158.152.97.199 X-Trace: news.demon.co.uk 910221936 nnrp-07:9714 NO-IDENT p850ug1.demon.co.uk:158.152.97.199 X-Complaints-To: abuse@demon.net X-Newsreader: TIN [version 1.2 PL2] Lines: 32 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!isdnet!newsfeed.wirehub.nl!bullseye.news.demon.net!demon!news.demon.co.uk!demon!p850ug1.demon.co.uk!not-for-mail barnacle (nailed_barnacle@junkfree.hotmail.com) wrote: : Showing my age now...but the first processor I ever used (mid/late 70s?) was a : Sinclair MK14...a huge 512 bytes of memory and a processor (8060?) which had : no jump instruction. Input and output were through a calculator keys/LED : display, but at least it came with a list of the instruction set for the cpu : and entry points to the monitor program...I never managed to make it do : anything useful! I still have my MK14, although the 7805 regulator shorted years ago and cooked many of the chips. One day when I've got nothing better to do I'll dig it out and fix it. It was my first machine as well. I've got a spare SC/MP (INS 8060) CPU in stock. I think you've mis-remembered some things. The standard ROM was 512 bytes, containing the monitor program. Standard RAM was only 256 bytes, but you could expand that with either another 256 bytes in 2111 RAMs (256*4 bit chips) or using an INS8154 RAM+I/O chip (128 bytes RAM, 16 I/O lines). There was a jump instruction. Like all other instructions that needed an address, the address was specified by an 8-bit displacement from one of 4 'pointer registers' in the CPU. The PC counted as one of the pointers. I am really digging in my memory now, but I think 90h was the opcode of a jump relative to the PC, and 90 FE was the simplest endless loop. It not only came with a list of entry points, but also a full schematic and a commented source for the monitor. The updated monitor came with a source listing as well. -tony ###### From: "Geoff Phillips" Newsgroups: alt.folklore.computers References: <71nuro$a8v$1@apple.news.easynet.net> <71qf1r$pc@p850ug1.demon.co.uk> Subject: Re: Anyone remember the predecessor to the ZX80? Date: Thu, 5 Nov 1998 08:55:30 -0000 Lines: 55 X-Newsreader: Microsoft Outlook Express 4.72.3155.0 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3155.0 NNTP-Posting-Host: 195.60.6.19 Message-ID: <36416a69.0@news.power.net.uk> X-Trace: 5 Nov 1998 09:05:45 GMT, 195.60.6.19 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.belnet.be!newsfeed.wirehub.nl!btnet-peer!btnet-feed2!btnet!news.power.net.uk!195.60.6.19 I came across the manual for the MK14 the other day when moving house. I eventually had 1 and 3/4 K of ram, all stacked up vertically. I found a picture of my system the other day, a huge rats nest of wiring, with an electrostatic printer attached, and a more or less sensible keyboard acquired from a junk shop. I must put this onto my web page at some point. Anyone here a member of the MK14 users group? I used to run this, a circulating newsletter (which inevitably would get stuck at an address) with snippets of code and circuit diagrams being mailed around the country. A lot of the people were in their early teens, I guess they'd all be early thirties now.. enough rambling for today. Geoff Tony Duell wrote in message <71qf1r$pc@p850ug1.demon.co.uk>... >barnacle (nailed_barnacle@junkfree.hotmail.com) wrote: >: Showing my age now...but the first processor I ever used (mid/late 70s?) was a >: Sinclair MK14...a huge 512 bytes of memory and a processor (8060?) which had >: no jump instruction. Input and output were through a calculator keys/LED >: display, but at least it came with a list of the instruction set for the cpu >: and entry points to the monitor program...I never managed to make it do >: anything useful! > >I still have my MK14, although the 7805 regulator shorted years ago and >cooked many of the chips. One day when I've got nothing better to do I'll >dig it out and fix it. It was my first machine as well. I've got a spare >SC/MP (INS 8060) CPU in stock. > >I think you've mis-remembered some things. The standard ROM was 512 >bytes, containing the monitor program. Standard RAM was only 256 bytes, >but you could expand that with either another 256 bytes in 2111 RAMs >(256*4 bit chips) or using an INS8154 RAM+I/O chip (128 bytes RAM, 16 I/O >lines). > >There was a jump instruction. Like all other instructions that needed an >address, the address was specified by an 8-bit displacement from one of 4 >'pointer registers' in the CPU. The PC counted as one of the pointers. I >am really digging in my memory now, but I think 90h was the opcode of a >jump relative to the PC, and 90 FE was the simplest endless loop. > >It not only came with a list of entry points, but also a full schematic >and a commented source for the monitor. The updated monitor came with a >source listing as well. > > >-tony > ###### From: nailed_barnacle@junkfree.hotmail.com (barnacle) Newsgroups: alt.folklore.computers Subject: Re: Anyone remember the predecessor to the ZX80? Date: Thu, 05 Nov 1998 19:58:43 GMT Organization: [posted via] Easynet UK Lines: 30 Message-ID: <71t02o$drq$1@apple.news.easynet.net> References: <71nuro$a8v$1@apple.news.easynet.net> <71qf1r$pc@p850ug1.demon.co.uk> NNTP-Posting-Host: nbarnes.easynet.co.uk X-Newsreader: News Xpress 2.01 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!feed1.news.luth.se!luth.se!news-peer-europe.sprintlink.net!news.sprintlink.net!Sprint!howland.erols.net!news-peer.gip.net!news-lond.gip.net!news.gsl.net!gip.net!easynet-tele!easynet-apple!egbert In article <71qf1r$pc@p850ug1.demon.co.uk>, ard@p850ug1.demon.co.uk (Tony Duell) wrote: >barnacle (nailed_barnacle@junkfree.hotmail.com) wrote: ---snip--- >I think you've mis-remembered some things. The standard ROM was 512 >bytes, containing the monitor program. Standard RAM was only 256 bytes, >but you could expand that with either another 256 bytes in 2111 RAMs >(256*4 bit chips) or using an INS8154 RAM+I/O chip (128 bytes RAM, 16 I/O >lines). my mistake - I had 512 bytes cos I saved up and bought that extra 256 bytes. The day I bought it a chap rode into the shop on a monocycle, looked around, and left without a word...strange days indeed! > >There was a jump instruction. Like all other instructions that needed an >address, the address was specified by an 8-bit displacement from one of 4 >'pointer registers' in the CPU. The PC counted as one of the pointers. I >am really digging in my memory now, but I think 90h was the opcode of a >jump relative to the PC, and 90 FE was the simplest endless loop. > I'd forgotten the offset - I seem to remember putting the address into the register and then changing registers to jump - was a long time ago though! >It not only came with a list of entry points, but also a full schematic >and a commented source for the monitor. The updated monitor came with a >source listing as well. Mine never had the schematic. But then, I had to send a letter to Uncle Clive threatening legal action if he didn't deliver *soon*... barnacle ###### From: ard@p850ug1.demon.co.uk (Tony Duell) Newsgroups: alt.folklore.computers Subject: Re: Anyone remember the predecessor to the ZX80? Date: 6 Nov 1998 00:36:19 -0000 Organization: P850 User Group Message-ID: <71tga3$1bm@p850ug1.demon.co.uk> References: <71nuro$a8v$1@apple.news.easynet.net> <71qf1r$pc@p850ug1.demon.co.uk> <71t02o$drq$1@apple.news.easynet.net> NNTP-Posting-Host: p850ug1.demon.co.uk X-NNTP-Posting-Host: p850ug1.demon.co.uk:158.152.97.199 X-Trace: news.demon.co.uk 910313464 nnrp-09:1438 NO-IDENT p850ug1.demon.co.uk:158.152.97.199 X-Complaints-To: abuse@demon.net X-Newsreader: TIN [version 1.2 PL2] Lines: 18 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.belnet.be!news-raspail.gip.net!news-lond.gip.net!news.gsl.net!gip.net!dispose.news.demon.net!demon!news.demon.co.uk!demon!p850ug1.demon.co.uk!not-for-mail barnacle (nailed_barnacle@junkfree.hotmail.com) wrote: : I'd forgotten the offset - I seem to remember putting the address into the : register and then changing registers to jump - was a long time ago though! You're thinking of the 'Exchange PC with pointer ' instruction. It was sort-of a non-reentrant CALL - the _updated_ PC was stuck into the specified pointer and the old contents of the pointer stuck into the PC. This mean that the program went to the subroutine (the address of which you'd put into the pointer), and at the end of the subroutine you did the same instruction to restore the address of the instruction after the 'call' to the PC. IIRC the revised monitor used pointer 3 in this way to execute user programs. Which means that exchanging PC with P3 was a return to monitor if you'd not used P3 for anything. -tony ###### From: autismuk@aol.com (AutismUK) Newsgroups: alt.folklore.computers Subject: Re: Anyone remember the predecessor to the ZX80? Lines: 41 NNTP-Posting-Host: ladder03.news.aol.com X-Admin: news@aol.com Date: 13 Nov 1998 20:54:54 GMT References: <71tga3$1bm@p850ug1.demon.co.uk> Organization: AOL, http://www.aol.co.uk X-Newsreader: AOL Offline Reader Message-ID: <19981113155454.19597.00000527@ngol03.aol.com> Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!newsfeed.cwix.com!152.163.199.19!portc03.blue.aol.com!audrey03.news.aol.com!not-for-mail In article <71tga3$1bm@p850ug1.demon.co.uk>, ard@p850ug1.demon.co.uk (Tony Duell) writes: >You're thinking of the 'Exchange PC with pointer ' instruction. It was >sort-of a non-reentrant CALL - the _updated_ PC was stuck into the >specified pointer and the old contents of the pointer stuck into the PC. >This mean that the program went to the subroutine (the address of which >you'd put into the pointer), and at the end of the subroutine you did the >same instruction to restore the address of the instruction after the >'call' to the PC. > >IIRC the revised monitor used pointer 3 in this way to execute user >programs. Which means that exchanging PC with P3 was a return to monitor >if you'd not used P3 for anything. This is not quite accurate. The SC/MP had a wierd CPU cycle ; virtually every machine does its fetch as read memory/increment PC. However, the SC/MP does a increment PC/read memory. There were 4 16bit registers P0,P1,P2,P3, P0 was the program counter. They were identical except you couldn't do an auto-indexed on P0, that was the immediate instruction. So if you reset it , the first instruction is at $0001 ; you can only execute $0000 by wrapping round from $FFFF. This made writing a TASM table for it somewhat difficult. If you want to know more, visit http://users.aol.com/mk14emu/ - emulators, portable source code, software, BASIC, tech stuff etc. Paul Robson Yes, I know it is completely mad, but I learnt to program on one of these - well not exactly, but the SC/MP Introkit which was the same thing, but wirewrapped and with a better keypad (not saying much...). Now all I want is a ROM image from a Camputers Lynx - any offers ? ###### From: autismuk@aol.com (AutismUK) Newsgroups: alt.folklore.computers Subject: Re: Anyone remember the predecessor to the ZX80? Lines: 15 NNTP-Posting-Host: ladder03.news.aol.com X-Admin: news@aol.com Date: 13 Nov 1998 20:54:55 GMT References: <71qf1r$pc@p850ug1.demon.co.uk> Organization: AOL, http://www.aol.co.uk X-Newsreader: AOL Offline Reader Message-ID: <19981113155455.19597.00000528@ngol03.aol.com> Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!newscore.univie.ac.at!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.cwix.com!152.163.199.19!portc03.blue.aol.com!audrey03.news.aol.com!not-for-mail In article <71qf1r$pc@p850ug1.demon.co.uk>, ard@p850ug1.demon.co.uk (Tony Duell) writes: >I think you've mis-remembered some things. The standard ROM was 512 >bytes, containing the monitor program. Standard RAM was only 256 bytes, >but you could expand that with either another 256 bytes in 2111 RAMs >(256*4 bit chips) or using an INS8154 RAM+I/O chip (128 bytes RAM, 16 I/O >lines). You could do both. By a judicious bit of track cutting you could disable 3 of the 4 monitor images ($200-$7FF) and install another 1.5k of RAM. However it would be a nightmare to code for this 2.125k arrangement ; it's hard enough using TASM because you have no absolute jumps....