Yes!

I've been sourcing 68000s from multiple places online, but it occurred to me I have no way to test them as they arrive, as I have no actual components to EPiC set up yet. To fix that, I needed a simple tester which could put the chips in "free run" mode.

The ideal tester would have a ZIF socket to allow you to painlessly swap multiple chips without wear and have a variety of clocks which would be selectable to test the chip's performance at varying speeds. An external clock connection would be helpful too, for future expansion. It would be able to be powered from a simple ATX power supply (since I have tons of those lying around and they do a great job of providing simple clean power at 3.3V, 5V and 12V) and would have an array of LEDs to show processor activity on the address bus, along with indicators for the FCx lines of the 68000.

In other words, something like this...

Looks like good stuff,
I've building 68xxx machines since 1985, bought my first one from Jameco. Had to pay import tax
( bugger ). Wire wrap is a no no at these speeds, but you have a pcb now. I have been using 6U
style eurocard, random wiring in Kynar 0.30 point to point, can't remember the website but with
high speed busses auto routed side by side crosstalk is a big problem.
Currently running a Coldfire MCF5208 @ 200Mc/s, that's how old I am, don't use hertz.
Bus speed 100 megs, don't use dram. Whats the point in using memory that forgets, you might as
well use a goldfish.
For your interface logic 74AC is plenty fast enough, and as a general rule 68xxx can be overclocked
by 25%
Go for a 68EC075 overclock it and get a big heatsink, if you need an FPU 68882's can be got up
to 50+ Mc/s.
Don't forget to tie your TDO TDI to GND or VCC otherwise it will go into JTAG mode and unless you've
got a simulator. Can't remember offhand what's high and low, but if you reply I'll lookup what works.
One more point don't apply 5V to the 68060 it will destroy the chip.It's 3.3V only with 5V tolerant I/O
( i.e. Address and Data lines )
ASC do static ram 512kx8 55nS access 4 off give you 2 Meg enough to be going on with
Why do you need an MMU, I realise you are a software guy, the whole thing grinds to a halt when you
get page fault. Simple don't access non-existant memory.
Plus you have DTACK or DSACK0 DSACK1 on the 060 put that ORed signal into a counter say 16 ticks
then generate an interrupt from the overflow of the counter.
Keep going I know its quite steep learning curve at first

Best Regards
Ian Hughes ( carronjack)
Computer Hardware Engineer ( Retd. )

To what would that roughly equate in MHz?







That applies to the entire family?



What is the 68075? Never heard of that one.



I'd appreciate that!



Thanks for the input!

Hi re your questions
Mc/s = Mhz
so roughly MCF5208 is doing 160 MIPS
sorry about the typo I meant MC68EC060RC75
There are 2 signals MDIS bar, CDIS bar or -MDIS -CDIS i.e.active when they are low 0V
tie these low until your program is running to your satisfaction, then bring them up to Vcc 3V
via a 1k resistor.The cache branch predictor can be very indeterminanistic.
meaning a different # of clock cycles between one run and the next.
I will look up the pin settings for you tomorrow for the JTAG interface and post them here.
These were derived after much pain and heartache.
RE the the clock speed, yep pretty much I've run 16Mhz ST68000 @ 28Mhz no probs
ran a MC68882 at 60mhz till my power supply failed
Interface logic keep it simple, no CPLD's or PALS you can build anything you need out of 74AC logic
Keep the faith It's there to be done, 'cos we can

Best Regards
Ian Hughes ( carronjack )

Good info, thank you!

Have you ever got a 68060 to freerun? I've been looking into what needs held high and low to make it happen. Here's what I've worked out so far:

Right found my 060 circuit diagrams in my very cluttered shed
TDI and TDS tied together up to Vcc via 1K resistor.
-TRST TCK -JTAG put to GND
- in front of the signal says it's active low.
That will stop it going into boundry scan.
I need to look at the -RSTI and -RSTO circuit to see what the hell I was doing
but I remember I had problems with it.
Will keep you posted.

Best Regards
Ian Hughes ( carronjack )

P.S. your code looks fine but if using the EC part
the Transparent Translation Registers are all zero i.e. no mmu

Found some more stuff,
following signals all pulled up via 1K resistor pack
-BGR,-TEA,-BB,-BR,-TR,-TA,-ILP0,-IlP1,-ILP2
next 1K resistor pack
-TIP,-TRA,-TS,-BTT,-CLA,-SNOOP
seem to remember had trouble when -BR was floating, 060 was waiting for an external bus master.
FOREVER!!
In answer to your last, no never had it free running, just checked and checked connections, and my
old 68000 system monitor came up first time.
Used AS assembler it doesn't support the 060, but if you define
as one of the first lines as PROC = 68040
its as near as dammit and you can use DC.W for writing to the regs not in the 040

If you can see light at the end of the tunnel
order more tunnel

Best Regards
Ian Hughes ( carronjack )

Thank you! Yes, most the 68060s I find for sale are EC models, so that'll be good.



Good to know, I'll add these assignments to my list.



Do these get tied high or low?



So the 68060 was running an unmodified 68000 monitor? Nice! Would you happen to have a copy of this monitor lying about? Or know of a better one I can find somewhere?



More tunnel it is! I love it!

Yes; thanks, Ian, and welcome.

In case anyone's wondering, c/s (or cps) means cycles per second. This self-descriptive unit got a new name ("Hertz") in the 1960's as I recall, but it still means cycles per second. And Mcps means MHz.

cheers
Jeff

Without looking at the 400+ page 060 manual,which I will do again
-RSTI is the reset to to the 060 -RST0 becomes active after 512 clock cyles
to reset external devices.
Yes in answer 2nd resistor pack all tied to 3.3V
I will find a copy of my quick and dirty 68K monitor for you and post it here!
If I can ever work out this internet of everything
Also find a copy of my very quick subroutine threaded FORTH
for 060 and ported to COLDFIRE
No I'm telling porkies, it was painfully tranposed over many weeks, by brute force
and ignorance. use CFASM excellent and freeware.

Best regards
Ian Hughes ( carronjack )

I worked on core store 32K ( huge) look it up

> Currently running a Coldfire MCF5208 @ 200Mc/s, that's how old I am, don't use hertz.
> I worked on core store 32K ( huge) look it up
Excellent - welcome! I've seen a core store up close, but never worked on one.

As I remember it was on a DEC system PDP
either an 11/03 or 11/23, the magnetic rings never went wrong it was always
the X,Y, or sense transistors which were BFY51's which were driving 1 amp plus
which was borderline according to transistor specs
Remember Towers International Transistor Selector?

Best Regards
Ian Hughes ( carronjack )

> Remember Towers International Transistor Selector?
Afraid not - either before my time, or not my area. I got into chip design about 1984, that was my start. Since then I've developed a progressively greater interest in the history of computers and computation, and taken to visiting museums like the one in Cambridge and the one on Bletchley Park.

Yes know of it, but never been it's a long way from the wilds of Scotland
But my mate also ex engineer, helped rebuild/restore the ELLIOT 603 ( GEC ).
He had some old hardware in his loft, and a complete bootloader on paper tape.
I know it's sort of before your time, but we were still using paper tape and ASR33
teletypes in 1988.

Best Regards
Ian Hughes ( carronjack )

Definitions :- Turnaround time
The time between feeding punched cards into an IBM 1200 card reader
and getting back the remains.

In what? A homebrew?