Microprocessor favourites?

[SiriusHardware]

I see that elsewhere (in the steam section) there's a thread devoted to 'valves we have hated', or words to that effect. I thought I'd follow on logically (yes, pun intended) by asking if you have any particular favourite microprocessor families or architectures -

If you're old school , then traditionally you fall into either the 6502 or the Z80 camp, and that largely stems from which computer you had when your interest in micro programming was at its zenith.

I've been playing with my Maplin Z80 system (which is being discussed elsewhere in another thread) and I'm really struck by how luxurious the instruction set was for an old 8-bit microprocessor. It's also the first time in years that I have directly programmed anything in HEX, and I find that the opcodes are all coming flooding back to me quite easily.

I have to say I never had the same fondness for the 6502, although I did gain some experience on it because a friend over the road had a BBC B.

[lastx33]

I'm the other way around - my fondness is for the 6502 having learned on a Rockwell AIM65 and used them in industrial controllers later.

[julie_m]

6502 will always have a special place in my heart for being what I learned first, having had bad experiences trying to talk to the Z80 in a ZX81. I then went back to the Z80 with a renewed interest, having learned enough of the underlying principles along with the easier (for me) assembly language.

[Radio Wrangler]

I was involved with a design team using the 4004 to start with, which quickly became the 4040 then 6800. Neighbours were working with 8008s, later, for me it was the 6809 then 68000. Some of the questions on my master's finals were about the comparison of Z80, 6502 and 6800, so I had to bone up on them. A colleague designed the Wireless World 'Forth Computer' for a bit of fun so we had a number of them kicking around.

In the CSC world, it was the 6809 that I liked.

David

[G6Tanuki]

My first contact with microprocessors was with the |D|I|G||I|T|A|L| LSI11/02 and LSI11/23 series, interfaced to a CAMAC crate for instrumentation control. Programmed in assembler, running under RT/11. It got quite interesting when you had several similar CAMAC crates linked together over a distance of several hundred yards on a length of pre-Ethernet coax, and you had to manage timing clashes.

After that I had a brief dalliance with the AMD2900-series of bit-slice processors doing real-time signal processing for various applications I'm still not allowed to talk about.

"Consumer" microchips never really excited me - the closest I got to playing that game was writing my own monitor/assembler package for the "Elektor" Junior Computer - and having to burn every byte of it into a pair of 2708 EPROMs by setting address and data on thumbwheel switches then stabbing the "Burn" button.

[GMB]

Yes, the 6502 was a nice little processor and certainly my first favourite.

Then the 68000 came along and that was really nice, just like a proper computer.

These days I would say the 16-bit PIC machines, e.g. the dsPIC33 series. They are cheap, powerful, still made in DIP, and again are like a proper computer and are easy to use.

[DragonForce]

Z80 all the way. Brought up on a ZX81/ZX Spectrum, a brief foray into the realms of the Commodore C-16 left me wondering how anybody could program for that particular CPU - no 16-bit address modes, 2MHz clock? What was that all about?

Then came the Amiga with its' MC68000 CPU and that just about blew everything else out of the water at the time.

Still have a fondness for the Z80...

DI
HALT

[G8HQP Dave]

My favourite has to be the J-11 - a PDP-11 on a chip (well, actually I think it was two chips on one carrier). In a box it becomes an 11/73 or 11/83, depending on clock speed. Nice orthogonal instruction set, with an architecture which looks rather like a parent of the 68000 series.

[cmjones01]

I'm going to vote for the ARM - an enormously clever piece of design which has endured and prospered like few others. In my collection I've got an original Acorn 'ARM Evaluation System' which was basically the first version of the chip to be available to the public. This was in 1985, I think. Now the design has become part of the fabric of modern life: there are literally billions of them out there. It's still technically elegant, too, and British to boot.

Chris

[julie_m]

I had experience of the 68000 at uni. One thing I don't like about it, is the way it stores its numbers the wrong way around. The units should be first! That's the order in which you do arithmetic!

[GMB]

One thing I don't like about it, is the way it stores its numbers the wrong way around.

Those of us from the mainframe era might be inclined to say that they store them the right way round.

When you write a number down you start with the big end!

[G6Tanuki]

Big-endian vs Little-Endian was always good for an enduring argument back in the 1970s/1980s. And woe-betide anyone who tried to transfer a 32-bit binary file from a PDP11 to anything-else without realising its odd byte-swapped storage mode.

[Of course then you also get into the various ways in which alphabetic characters are represented - Baudot, BCD, EBCDIC, ASCII, RAD50, FIELDATA - and then in turn how these are stuffed into native 8- 12- 16- 24- 32- 36- or 60-bit-long machine-words].

Oh what fun!

[woodchips]

8085, not perfect but wrote a lot of assembler for that, including a BASIC. For home use the 6800 and 6809. Most elegant must have been the 11/23 with RSX11M operating system, ahh.

Ah, the byte ordering conundrum, at least you never used a TI9900 where they decided the most significant bit in the word was zero, yes, really, and then 32 bits came along!!!!

Note that no one likes the 8086, correctly, evil piece of junk. If IBM had used a 68008 in the PC then now no one would remember the 8086, at all.

[lesmw0sec]

Made a good living out of Z80's in various bits of kit and really loved the 68000.
Retired now, but messing around with PIC's. The reduced instruction set is a bit of a pain compared to the Z80, but they really fly. Never quite grasped the point of using C for them, rather than assembler. The C examples I've seen are so obscure, you might as well do it with bits and bobs.

Les.

[hysteresis]

Originally Posted by GMB

... the 6502 was a nice little processor ...

It still is - now manufactured by The Western Design Center and sold, by the likes of Mouser, for £4.87.

[Gulliver]

Originally Posted by DragonForce

Z80 all the way. Brought up on a ZX81/ZX Spectrum, a brief foray into the realms of the Commodore C-16 left me wondering how anybody could program for that particular CPU - no 16-bit address modes, 2MHz clock? What was that all about?

The C64 was just as difficult to program. I maintain that is why the UK spawned a generation of programmers and the US a generation of gamers. The Sinclair and BBC computers were designed to be programmed as well as to perform the tasks of a computer. The Commodore line of home computers was emphatically never designed to be programmed by the user. Horrid machines to code on or for. I tried and gave up.

[Marconi_MPT4]

Has to be 8080/8085/Z80 series of 8 bit microprocessors. Probably has something to with low level programming in hex code or assembler, the whole program had to be designed and structured before coding.

Z80 was extensively used in products and to this day still recoil at having to sit around in code review meetings reviewing assembler printed on reams of 132 column fanfold paper! Sometimes for a week at a time....

Assembler code development took place on a Rank Xerox green screen computer running CP/M operating system with 256k memory and two 8" Shugart floppy drives.

Happy Days!

Cheers
Rich

[mole42uk]

I started with the 4004, followed by SC/MP, then got into Z80, then I blagged a Nascom II which settled it. Programming in machine code was quite easy with Z80, we had to do that because we were using code that optimised clock cycles on the limited-speed processor. Assembly language couldn't cope especially when we had to build everything into multiples of 8k EPROM.

Richard

[SiriusHardware]

Originally Posted by mole42uk

I started with the 4004, followed by SC/MP, then got into Z80

As a matter of interest what were you running an SC/MP in? An MK14? Or something else (the Elektor system maybe? - a friend of mine built that).

[SiriusHardware]

Originally Posted by lesmw0sec

The C examples I've seen are so obscure, you might as well do it with bits and bobs.

Ah, this was me until just a few years ago.

I used to describe C as a 'write only' language because C code is so horrible to read, unless you wrote it yourself of course.

But actually, PICs were the reason I finally persevered with 'C' - I couldn't stand some of the hardware quirks of the PICs, such as the inadequate program counter which made it dangerous to let subroutines or lookup tables fall across page boundaries - and don't get me started on all that tedious bank switching stuff to get in and out of the various RAM banks and special function registers. 'C' compilers for PIC hide all that by handling it all silently in the background, but you can still write the code, as I do, in assembly language-like fashion so that each line of code only performs one action, thereby making it much more human-readable.

That said, there's still no substitute for assembly language even on PIC if you have something that has to be done very, very, very quickly with no unnecessary code overhead. I've just done something which required a PIC to emulate a static RAM, whereby the PIC had to respond to a /CE pulse, read 16 address lines and present the corresponding data (stored in PIC internal RAM) to an 8-bit bus all in less than 2uS. I only managed it by raising the PIC clock speed to 40Mhz and writing the code in pure assembly language.