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The Official 6502 Versus Z80 Religious War Thread. - Page 2 — Parallax Forums

The Official 6502 Versus Z80 Religious War Thread.

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  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2013-12-22 14:31
    Heater. wrote: »
    Z80 -> CP/M -> boring green screens and Excel.

    For CP/M SuperCalc, then VisiCalc, as I recall. (VisiCalc came first to the 6502.) Don't think Excel ever was available for CP/M. I thought it was MS/PC-DOS / Windows.

    My recollection was that both Excel and Word ran under a p-code interpreter, and 64K just couldn't cut it. I may be mis-remembering this, though.
  • potatoheadpotatohead Posts: 10,261
    edited 2013-12-22 14:53
    http://en.wikipedia.org/wiki/Multiplan

    That is the pre-excel application Microsoft did release for CP/M.

    Hmmm, I'll have to get a spiffy CP/M card for my Apple... That way I would have a Z80 in house.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-12-22 16:10
    There are many FORTH kernels for both the 6502 and the Z80, and all their variants. There is no loser in this war. :)
  • 4x5n4x5n Posts: 745
    edited 2013-12-22 21:24
    Actually of the 8bit micros the 6809 was without question beats all the rest hands down!!! In the early days of the mcu the 68hc11 reigned supreme!! :-)
  • Martin_HMartin_H Posts: 4,051
    edited 2013-12-23 06:47
    4x5n wrote: »
    Actually of the 8bit micros the 6809 was without question beats all the rest hands down!!! In the early days of the mcu the 68hc11 reigned supreme!! :-)

    I quite liked the 6809 too as we used it in RPI's microprocessor classes. But I made a living for a year writing 6502 assembly code, so it will always be my top choice of microprocessors from that era.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-12-23 08:08
    I don't have an opinion re: 6502 vs. 8080/Z80. The reason I picked my first PCs (Poly88, TRS80, Otrona Attache), which just happened to use the Intel/Zilog-family processors, was for the screen resolution (64 char/line vs. 40 char/line for the color computers). Resolution mattered more to me than color, and the 2x3-pixel graphics characters of the Poly88 and TRS80 yielded finer on-screen images than those of the color computer offerings of that era.

    -Phil
  • Martin_HMartin_H Posts: 4,051
    edited 2013-12-23 10:21
    Resolution mattered more to me than color, and the 2x3-pixel graphics characters of the Poly88 and TRS80 yielded finer on-screen images than those of the color computer offerings of that era.

    The Atari initially had a 40x24 full color screen, but it had a number of undocumented video modes useful for higher resolution monitors. I bought a replacement ROM that provided 80x24 video and a debugger. It was a pretty sweet setup at the time.
  • potatoheadpotatohead Posts: 10,261
    edited 2013-12-23 11:44
    Yes, I had an 80 comumn software driver for my Atari. Worked very reasonably on a composite monitor. Eventually got an Apple for better software and 80 column screen. My favorite was the CoCo 3, which offered a 16 color 80 column screen. :)

    Early on, I wrote a lot of 6502 code on a 40 column screen. Wasn't bad on the Atari. I had a cartridge assembler MAC/65 and a great ROM debugger / monitor. Made that machine almost as sweet as the Apple was.
  • Martin_HMartin_H Posts: 4,051
    edited 2013-12-24 08:10
    In case this thread didn't offer enough evidence of the 6502's awesome factor. Here are neat 6502 and Propeller projects:

    http://propeddle.com

    http://www.brielcomputers.com/wordpress/?p=290

    The propeddle looks neat, but it looks like he's out of pcb 's.
  • jac_goudsmitjac_goudsmit Posts: 418
    edited 2014-01-15 06:34
    Martin_H wrote: »
    The propeddle looks neat, but it looks like he's out of pcb 's.

    I'm not out of PCB's... I wish the problem was that simple :-)

    The latest PCB I designed and ordered from Oshpark (Rev 7 (EDIT: Oops, I meant Rev 8)) was for the Propeller Expo 2012 (yes 2012). But I had made a mistake and had forgotten to run an ERC/DRC check so there's a missing connection on it. It can be made to work pretty easily but you have to short two (almost adjacent) pins to each other. I still have a number of kits available; if you want one, send me a PM and we can work something out.

    Another problem is that the most recent Propeddle PCB was designed to be used with the Propeller Platform which pretty much died after the QuickStart board was introduced. Also, because of timing restraints, I had to use non-standard pins for video so even if you got a video board for the Propeller Platform it was still necessary to modify it to use the different pins. I really should design a new PCB that has everything on it (Propeller, 6502, glue logic, connectors) but I can't use Eagle for it anymore because it would take up too much space. Besides, it's a commercial product now, so I can't use the free version of Eagle anymore, and they charge so much for their cheapest commercial license that I'll never be able to recoup the costs. I started learning Kicad but I just haven't had enough time.

    I did a quick test a while ago to see if the circuit would fit on a Propeller USB project board (#32810) and it does. I've been wanting to do a wire-wrap project for a while and I figured I should make a wire-wrapped version of Propeddle as a proof-of-concept to show that it will fit on a Propeller Project board, and I should take pictures and make e.g. an Instructable out of it, so that others can make their own without having to wait until I finally get a PCB done.

    At Propeller Expo 2013 I had a little demo set up, but Potatohead was sitting right next to me and he totally stole the show with his FPGA board running Prop2 demos :-). I was also scheduled to do a presentation but just before the Expo my boss threw a metric boatload of work at me so I ran out of time to prepare the presentation and had to cancel. Hopefully this year will be better, but don't hold your breath :-)

    By the way Martin_H you pasted a link to Vince Briel's Replica 1, but his OSI Superboard project (on which I had the honor to co-operate) has much more Propeller involvement: In the Replica 1, the Propeller merely acts as serial terminal (I think), but in the OSI project, the Propeller emulates the ROM, the video hardware and the serial port (and perhaps in the future, the floppy drive). The concept is pretty much a specialized version of my Propeddle project. It's a work in progress and it may take a while before he's done, but I'm pretty excited about it.

    ===Jac
  • potatoheadpotatohead Posts: 10,261
    edited 2014-01-15 09:04
    "At Propeller Expo 2013 I had a little demo set up, but Potatohead was sitting right next to me and he totally stole the show with his FPGA board running Prop2 demos :-)"

    Aww man! I didn't know this. Regrettable, because I would have spent some time chatting with you. Dang! My mind did not make the mental connections. Let's make sure and get some time to talk this year.
  • Heater.Heater. Posts: 21,230
    edited 2014-01-15 11:11
    So where is the 6502 emulator that runs on the Propeller?
  • potatoheadpotatohead Posts: 10,261
    edited 2014-01-15 13:07
    We have one written initially by Eric Ball and it's been used in the NES Emulator posted here a long time ago.
  • AleAle Posts: 2,363
    edited 2014-01-16 03:13
    When I started working as a developer (19 years ago) I had to write 6801/6809 (not that much) and 68HC11 assembler (plenty), for a couple of years. I thought in those days that the Z80 was better. Now, I know that at least for the 6809, it wasn't.
    I wrote a verilog 6809 core recently, and that thing is quite slow. Yes, it has fancy addressing modes but they are very expensive...
    The 68000 is not related to the 6800 or to the contemporary 6809, it borrows very heavily from the pdp-11. Already in '75 it was recognized that 16 bit processors were obsolete, at least the ones that could only address 64 k... if not, we wouldn't have had the vax :)
  • Martin_HMartin_H Posts: 4,051
    edited 2014-01-16 04:38
    So I bought one of the Propeddle kits. I plan to use it to blink an LED in 6502 assembly and general noodling.
  • Heater.Heater. Posts: 21,230
    edited 2014-01-16 07:28
    Ale,

    I was wondering how this adds up. 19 years ago was 1994 and the 6809 was already 16 years old. Why would anyone have still been using it then?

    But it seems the 6809 was still in use, at least by Motorola in their radio systems, into the early 2000s. Also it seems the 6809 found it's way into traffic light controllers, in which case I bet there is still a load of them working for us out there.
  • potatoheadpotatohead Posts: 10,261
    edited 2014-01-16 08:49
    Lots of people built their own 6809 embedded development systems too. They would run things like FLEX or OS/9, FORTH, etc... as part of a small, well controlled development / service tech environment.

    The guy who taught me the 6809 did this and had quite the niche business and ran a multi-user OS/9 system in his home with various terminals and such.
  • Heater.Heater. Posts: 21,230
    edited 2014-01-16 08:54
    My home made 6809 board was old school, HEX keypad, seven segment displays and only 2K or so of RAM.
  • potatoheadpotatohead Posts: 10,261
    edited 2014-01-16 09:06
    Double post.

    So, let's take this post and talk some 6502 / 6809.

    Ale mentioned the 6809 was slow, due to expensive and fancy addressing modes. Well, if used in the most direct fashion, the 6809 was a little cycle hungry, but really comfy to program in. It had things like program counter relative, plus index register X with auto increment! Spiffy! One could chew up 12-14 cycles doing that kind of luxurious programming. X is 16 bit too, just because.

    A 6502 was a lot dumber, but it peaks out at 7, maybe 8 cycles for something complicated, and it's got a lot of 3-5 clock workhorse instructions that get stuff done.

    Both chips have some nice code density / speed trade-offs, but the 6809 really had more "dynamic range" in this respect. One could author some really small, tight code that wasn't exactly the fastest code, but often very smart, relocatable, reentrant, etc... Or, one could stick with the simpler, shorter, faster instructions and reach a much closer parity with the 6502 in terms of size / cycle count / throughput.

    It's that property that people really liked and used IMHO. A 6809 can actually be abused and move memory fast. Faster than pretty much any other 8 bitter. (use the stack and push pull through as many registers as you can spare) Or, it can run code packed into little, tiny places. That and a nice MMU made for a nice, powerful system, all of which led to FLEX, OS/9 type OS software being developed, first by Moto to show off, and then later by others to continue on.

    BTW: 6809's were great Forth machines. The one guy I knew doing that did amazing things in very little RAM, fast. Two stacks, one system, one user, and all that smart indexing really played well in Forth land.

    6502 ended up embedded all over the place, and still is. WDC sells a 14Mhz version that can be coupled with fast RAM made today. I have always kind of wanted to build a system up. 14Mhz 6502 is quick. Not too smart, but really quick! :)
  • DaveJensonDaveJenson Posts: 375
    edited 2014-01-16 09:25
    My first microprocessor design used a 6502. I chose that one because I could run the clock from a pushbutton. That way I could examine exactly what was happening at each clock. The 6502 used memory-mapped I/O (no dedicated/specific I/O pins). I wire-wrapped the entire thing. Had Forth in EPROM, I think 2K RAM, video out on a separate (wire-wrapped) board. Had a full qwerty keyboard (with 8051 embedded). I even had a hardware multiply board that used a ROM lookup table and produced a result in 16 clocks.

    I went on to use a 6809 (running Forth again) to display Korean characters on a CRT for a CP/M computer produced by Novell Data Systems (before they became Novell).

    Ah "the good old days"!
  • jac_goudsmitjac_goudsmit Posts: 418
    edited 2014-01-16 14:23
    potatohead wrote: »
    "At Propeller Expo 2013 I had a little demo set up, but Potatohead was sitting right next to me and he totally stole the show with his FPGA board running Prop2 demos :-)"

    Aww man! I didn't know this. Regrettable, because I would have spent some time chatting with you. Dang! My mind did not make the mental connections. Let's make sure and get some time to talk this year.

    No biggie. It was an honor to sit in your shadow :-)

    I didn't really have a good setup anyway (it was basically the same as the year before, only I was using a tiny black and white TV instead of a serial port to my PC; all because the Big Time Window that I had planned on using for writing some software, had been slammed shut by my boss)

    I really have to write some software that looks interesting from a distance (lots of colors and blinking 7-segment fonts and stuff) and show it on my 13" color TV or my 21" flat screen instead of using a tiny 4" black and white CRT or that pocket TV that I got from Parallax that doesn't really work all that well.

    Something that says: Hey, come see this, if you give this to your kids instead of that iPad, they can learn how a microprocessor works and eventually design and build their own computers.

    ===Jac
  • jac_goudsmitjac_goudsmit Posts: 418
    edited 2014-01-16 14:25
    Martin_H wrote: »
    So I bought one of the Propeddle kits. I plan to use it to blink an LED in 6502 assembly and general noodling.

    Thanks for ordering!

    Of course, blinking an entire video screen using 6502 assembly is much more fun than just blinking an LED :-)

    ===Jac
  • potatoheadpotatohead Posts: 10,261
    edited 2014-01-16 19:55
    You could get a video capture device. I use this with my laptop to great effect. It's nice, can fill the screen, and it all just sort of works well on composite. That's been my goto solution almost since the beginning. I do use various displays, but the primary way I like to do it is with the video capture. On P2 we can stuff a lot into a composite display in a window, even when it's intended for HD. Display it anyway, and have that window right there on the computer with the code. :)

    In any case, let's make sure and catch up this year. I want one of your kits. May order soon, time and resource allowing. Nicely done.
  • TonyDTonyD Posts: 210
    edited 2014-01-17 05:56
    Heater. wrote: »
    I was wondering how this adds up. 19 years ago was 1994 and the 6809 was already 16 years old. Why would anyone have still been using it then?

    But it seems the 6809 was still in use, at least by Motorola in their radio systems, into the early 2000s. Also it seems the 6809 found it's way into traffic light controllers, in which case I bet there is still a load of them working for us out there.

    In the late 80's & early 90's our local college was using 6809 & 68000 for teaching low level programming.

    Also don't forget a lot of pin ball machines and one-arm bandits used the 6809 and you still see them in pubs and clubs today :-)
  • jac_goudsmitjac_goudsmit Posts: 418
    edited 2014-01-17 06:12
    potatohead wrote: »
    You could get a video capture device. I use this with my laptop to great effect. It's nice, can fill the screen, and it all just sort of works well on composite. That's been my goto solution almost since the beginning. I do use various displays, but the primary way I like to do it is with the video capture. On P2 we can stuff a lot into a composite display in a window, even when it's intended for HD. Display it anyway, and have that window right there on the computer with the code. :)

    I know a video capture device is a great way to work on the project without the monitor taking up space. Especially since my main development system is the laptop which is usually on a tray where there's not a lot of leftover space for things like monitors :-)

    The point I was trying to make is that I realized that at an event like the Parallax Expo (or the Bring A Hack Dinner after the 2013 Bay Area Maker Faire), a small circuit board and a text window on the screen of a laptop or a 4" B/W TV is not going to get much attention. At the next opportunity to show the project, I'll definitely put some more effort into presentation. But first I really need to get a PCB done that has everything on it. I was hoping I would have some time during the recent Christmas/New Year vacation but I ended up spending even less time on electronics/software projects than usual :-(
    In any case, let's make sure and catch up this year. I want one of your kits. May order soon, time and resource allowing. Nicely done.

    If there is an Expo again, I'll try to make it again too. My wife has some family living in Northern CA so it's fun to combine a family visit with the Expo and the Bay Area Maker Faire. But I understand that Ken only wants to do an Expo this year if the Propeller 2 will be ready.

    Thanks!

    ===Jac
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