At 05:42 PM 6/7/02 -0500, you wrote:
>Didn't see anyone else mention this story, though it isn't exactly
>front-page news...
>
>China bans toxic American computer junk:
> http://www.guardian.co.uk/international/story/0,3604,725756,00.html
>
>Maybe this will help save just a few systems...
>
>-Toth
Yes, but I fear we'll soon be swimming in computer scrap. The amount of scrap that we've been exporting is tremendous.
Joe
On Jun 7, 13:05, Richard Erlacher wrote:
> You may be confused about this. I don't know of a single NMOS 6502 that
> didn't adhere to the MOS-technology instruction set. There's no telling
> whether that included the undocumented opcodes, but since Synertek and
> Rockwell used the MOS mask set, I suspect there was no difference. The
later
> Synertek parts may have been different since they shrank the die and got
a bit
> more speed, offering a 4 MHz 6502-C, which was an NMOS part and worked
> perfectly in NMOS-targeted systems that didn't work with the later CMOS
parts.
There certainly were differences between the sets of undocumneted opcodes
>from different manufacturers of 2MHz 6502A parts. I remember one or two
"clever" bits of software that failed on some BBC Micros for that very
reason. Sean is absolutely right to avoid undocumented codes.
--
Pete Peter Turnbull
Network Manager
University of York
Richard,
Does anyone have a PDF copy of the Motorola 6800
chip datasheet? I downloaded a copy from somewhere
yesterday and the strangest thing happens. When viewing
the PDF, it shows on the screen as a positive image but
when printing, it prints as a negative.
On the print page make sure 'Print as image' is ticked.
This should fix the -ve image.
Lee.
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>From: ard(a)p850ug1.demon.co.uk
>
>> >Not on the 6800 but I believe some FORTH chips have that problem.
>
>Incidentally, some Xilinx FPGAs will spectacularly overheat if fed bogus
>configuration data. You can get 2 internal buffers driving the same line
>in oposite directions. The CAD software is supposed to never generate
>such a configuration file, of course, but if there's a bug in the
>software, or the data is corrupted on download to the chip, it can
>happen. Don't ask how I found that out.
>
>
>> Instructions that would continuously increment the address
>> are vary useful for debugging address decoding problems.
>
>True...
>
>> On an 8080, about the only useful sequence is to have
>> a pop and jmp, using 4 locations.
>
>What's wrong with forcing a NOP (00) onto the databus. That should make
Hi
This does require that you have full control of the bus. I have
used the 00H as well as the 0FFH. When you have a partially working
bus, running code is prefered because simply pulling the ROM
may not always work Some broken device may inject
and instruction and break the loop. It is good to have all
three methods of running addresses in your tool box.
It is too bad that the simple 00 and 0FFH codes don't work for all
processors, like the 8080's.
Dwight
>the PC increment from 0 to 0xFF. Or force RST38 (0xFF) onto the databus.
>That will cause repeated fetches from location 0x38 with memory writes of
>39 00 to every 16 bit word of memory in decreasing address order -- it's
>pushing the return address (0x38+1 onto the stack, of course). Both
>instructions are easy to force and have very recognisable effects on the
>bus lines.
>
>One of the tests for the TRS80 Model 1 (Z80 based) is to pull the ROMs.
>The databus is pulled high, so the CPU should execute RST38s. It writes
>the return address to the video memory (as well as user RAM, of course),
>giving a display of alternate '9's (0x39) and '@'s (0x00 -- the TRS-80
>video display circuit ignores bit 6 IIRC).
>
>-tony
>
>
>Hey, you know what? I missed the beginning of this thread, but this is
>exactly the sort of behavior you get from a modem which requires a 9V AC
>power supply, when you run it with a 9V _DC_ supply.
Interesting. The wall wart I used with the modem is the one that was in
the box along with all the other assorted parts. The wart has a label
marking it as the same manufacturer as the modem, so I didn't even think
about the fact that it might not be the RIGHT wart. Maybe it is really
>from a different model modem.
I didn't persue the issue much since the modem is a Global Village for a
Mac. They are great modems... IF you have the right software. Without it,
they tend to be a pain in the ass. Since I don't have the exact software
that shipped with this model, and since the firmware claims it is a
French-Canadian modem, and I only have US-English software... I didn't
waste much time working on it.
But maybe I will do a little more research and see if it really should
have an AC adaptor, not a DC one.
Thanks
-chris
<http://www.mythtech.net>
Hello everyone;
I have noticed that OpenVMS 7.2 doesn't seem to recognize all
of the physical memory in my vaxstation 4000/60; I am sure
that I have 32 MB (8MB mainboard + 6 x 4MB modules) and
in fact it is recognized by the prom:
KR46-A V1.1-31E-V4.0
08-00-2B-2A-F8-AB
32MB
|||||||||||||||||||||||||||||||||||||||
OK
85 RESTART SYS
>>>
>>> show config
KR46-A V1.1-31E-V4.0
08-00-2B-2A-F8-AB
32MB
DEVNBR DEVNAM INFO
------ -------- -------------------------------
1 NVR OK
2 LCG OK
HR - 8PLN FB - V1.1
3 DZ OK
4 CACHE OK
5 MEM OK
32MB = SY=8MB, S0/1=8MB, S2/3=8MB, S4/5=8MB
6 FPU OK
7 IT OK
8 SYS OK
9 NI OK
10 SCSI OK
0-ST31200 5-TZ30 6-INITR 7-CD-ROM
11 AUD OK
>>>
Similarly, the TEST 100 command tests all of the hardware and
there aren't any errors. So, as far as the diagnostics in the
Prom are concerned, the system has 32MB of memory and it tests OK.
But, this is what I get under OpenVMS:
$ show memory
System Memory Resources on 6-JUN-2000 16:25:53.84
Physical Memory Usage (pages): Total Free In Use Modified
Main Memory (16.00Mb) 32768 8459 22775
1534
Virtual I/O Cache Usage (pages): Total Free In Use Maximum
Cache Memory 11 0 11 51649
Slot Usage (slots): Total Free Resident Swapped
Process Entry Slots 48 25 21
2
Balance Set Slots 43 23 19
1
Dynamic Memory Usage (bytes): Total Free In Use Largest
Nonpaged Dynamic Memory 1359360 103552 1255808 12480
Paged Dynamic Memory 717824 435488 282336 434448
Paging File Usage (pages): Free Reservable Total
DISK$VAX4000SYS:[SYS0.SYSEXE]SWAPFILE.SYS
6240 6240
7200
DISK$VAX4000SYS:[SYS0.SYSEXE]PAGEFILE.SYS
55557 15536 65536
Of the physical pages in use, 10827 pages are permanently allocated to
OpenVMS.
So, what is happening here? Does anybody have some suggestions
as to why OpenVMS doesn't see/want to use the remaining 16MB?
Best regards,,
Carlos.
________________________________________
Acceso r?pido a Internet con Epm.Nethttp://www.epm.net.co
>Two 84-key AT keyboards sold on eBay yesterday for $122.50 and $127.50.
>Now I know how I'm going to pay the house note next month.
Cripes, and I just gave away two of them to go with the two ATs and
matching CGA monitors I gave away.
Good thing I still have a supply of them I can sell
-chris
<http://www.mythtech.net>
This is off topic, since the wall wart is only a few years old, but there
are some great electrical people here, so I am asking because I know
someone will know the answer.
I have a wall wart to a modem. I got the modem and wart in a box of used
stuff (ooh, some of which was more than 10 years old, so at least there
is a reference to on-topicness).
The modem failed to work from the day I got it. Today, someone that has
the same modem asked if I had a power supply they could have. I planned
to give them mine, since I have no real use for it.
But before I mailed it to them, a voice went off in my head telling me to
stick it on a meter first. It's label says it is a 9vDC, 400mA Pos-tip
wart. But when I hook it up to a meter, I get 15v DC off it.
That seems a little high, even for something under no load. Should I
safely assume the wart is no good, and point the person elsewhere (Rat
Shack sells a usuable unit for only about $14, so it isn't like the
person has no other choice). Or is it normal for a 9v supply to put out
15 volts? Any that I have measured in the past have not been THAT far off
(I was expecting to maybe get 10 or 12 volts, but not 15).
If this thing has been pumping too much voltage, that might explain the
dead modem I have (or the modem could have been used as a soccer ball,
who knows, it was dead when I got it). I just don't want to send the
person a bad supply, and have them fry their modem when they try to use
it.
-chris
<http://www.mythtech.net>
Hello, all:
Does anyone have a PDF copy of the Motorola 6800 chip datasheet? I
downloaded a copy from somewhere yesterday and the strangest thing happens.
When viewing the PDF, it shows on the screen as a positive image but when
printing, it prints as a negative.
Thanks.
Rich
Rich Cini
Collector of classic computers
Build Master for the Altair32 Emulation Project
Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/
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