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chip swelling up and getting fried

T

Tom Del Rosso

Jan 1, 1970
0
John Larkin said:
I loved the 286 ("brain damaged CPU" to quote Bill Gates) trick to get
out of protected mode back into real mode. The CPU designers forgot to
allow an instruction to do this, so somebody patented the idea of
sending a command to the keyboard controller to reset the CPU. I think
early versions of Windoze actually used this technique.

Well, sure they used it. IBM designed the AT to do that, with the
keyboard controller connected to drive CPU reset, and programmed to
assert reset on I/O command, so of course Windows used it. They were
indended to.

I don't think anybody forgot to include an instruction. They just
assumed that if any system used virtual memory mode then that system
would only have to switch modes one way, during initialization. They
just didn't figure on running legacy 8086 code that was aware of
segments but assumed they were consecutive in real memory. Maybe it
would have worked in protected mode running 8080 code that wasn't even
aware of segments.
 
T

Tom Del Rosso

Jan 1, 1970
0
Bill Bertram said:
Motorola didn't make the 6502, I think you mean the 6800.

Right, the 6502 was made by Rockwell. They didn't put that feature in
their CPU. Just the space shuttle.
 
D

DJ

Jan 1, 1970
0
Hi Mr Watters
1.Yes it requires the 3v3 to come up before 1v comes up.That is proper.
2.I need to check up the unprotected I/O's
regards
DJ
 
D

DJ

Jan 1, 1970
0
No the chip is not 5 v tolarent.
but yes it was definitly working for sometime, before it blew up.

thanks
DJ
 
D

DJ

Jan 1, 1970
0
Can it be an unrecognised floating Pin?because I have many TP's which
we have left unconnected.Can that be an Issue?
Thanks
regards
 
D

DJ

Jan 1, 1970
0
Can it be an unrecognised floating Pin?because I have many TP's which
we have left unconnected.Can that be an Issue?
Thanks
regards
 
R

Rich Grise

Jan 1, 1970
0
Tom said:
Right, the 6502 was made by Rockwell. They didn't put that feature in
their CPU. Just the space shuttle.

I played with some 6502s once. I remember I really liked them.
I just went and looked up the instruction set, and now I
remember - page zero. Essentially, a set of 256 registers. :)
And two, count'em, two, index registers.

The 256-byte (IIRC) stack never seemed to be a limit. I remember
thinking, "This is very orthogonal."

And I remember the 6800 opcode as HCF (halt & catch fire) - but
I remember it as just turning all the address and data lines
into a big free-running binary counter.
 
D

DJ

Jan 1, 1970
0
Ok guys,
I have some more observation.The chip starts heating up only when
the reset is deasserted.
The BGA Chip has only one reset which is the reset for its PCI
interface also,
Now the moment I de assert the PCI interface it starts heating up, the
device is connected to a PCI host.So the power sequencing issues are
laid to rest.
regards
DJ
 
S

Sir Charles W. Shults III

Jan 1, 1970
0
Yes, it certainly could. On nearly any device today, any and all unused
inputs must be tied to a terminal through a pullup or pulldown resistors.
This even applies to pins that are bidirectional in most cases, because on
reset (or execution of certain instructions) those pins can become inputs
and if not tied somewhere, they float.

Cheers!

Sir Charles W. Shults III, K. B. B.
Xenotech Research
321-206-1840
 
E

Ed Price

Jan 1, 1970
0
Tom Del Rosso said:
Right, the 6502 was made by Rockwell. They didn't put that feature in
their CPU. Just the space shuttle.

Rockwell only second-sourced the 6502.

The 6502 originated with MOS Technology (later bought and merged into
Commodore).
The MOS guys were mostly from Motorola, and went out to do their own thing.

Do the names KIM, AIM-65, SYM-1, PET, Apple II, VIC-20, C-64, Atari &
Nintendo remind you of anything?
I believe the 6502 was the most-sold microprocessor ever.

Ed
 
J

John Woodgate

Jan 1, 1970
0
Do the names KIM, AIM-65, SYM-1, PET, Apple II, VIC-20, C-64, Atari &
Nintendo remind you of anything? I believe the 6502 was the most-sold
microprocessor ever.

You can add 'BBC Micro' to that list.
 
M

Mjolinor

Jan 1, 1970
0
I believe the 6502 was the most-sold microprocessor ever.
Surely that woud be the Z80 and it's derivatives
 
K

Keith Williams

Jan 1, 1970
0
Surely that woud be the Z80 and it's derivatives
Depending on how/what you count, surely x86 (8088?) or perhaps 8051 and
their derivatives have to be most sold microprocessors. There are
something like 2E9 (~100M/year over 20 years) x86 processors sold so
far. Embedded '51s? Who knows!
 
M

Mike

Jan 1, 1970
0
Do the names KIM, AIM-65, SYM-1, PET, Apple II, VIC-20, C-64, Atari &
Nintendo remind you of anything? I believe the 6502 was the most-sold
microprocessor ever.

You can add 'BBC Micro' to that list.[/QUOTE]

.... And Oric-1 and Oric Atmos!
 
K

Ken Taylor

Jan 1, 1970
0
Mike said:
You can add 'BBC Micro' to that list.

... And Oric-1 and Oric Atmos!
--[/QUOTE]
I have a chess computer here at home that uses a 6502. Plays a crap game,
and mighty slowly, but a chess computer it is!

Ken
 
T

Tom Del Rosso

Jan 1, 1970
0
Ken Taylor said:
I have a chess computer here at home that uses a 6502. Plays a crap
game, and mighty slowly, but a chess computer it is!

In '78-'79 Popular Electronics had a computer chess project with a
"2650", which I remember noticing was a 6502 with the digits rearranged.
Apparently it was a completely different CPU.
 
K

Ken Taylor

Jan 1, 1970
0
Tom Del Rosso said:
In '78-'79 Popular Electronics had a computer chess project with a
"2650", which I remember noticing was a 6502 with the digits rearranged.
Apparently it was a completely different CPU.
Yeah, I built my first computer with that CPU, way back when, probably
around the same timeframe. An 'Electronics Australia' project.

Ken
 
T

Tom MacIntyre

Jan 1, 1970
0
In '78-'79 Popular Electronics had a computer chess project with a
"2650", which I remember noticing was a 6502 with the digits rearranged.
Apparently it was a completely different CPU.

That was the heart of the KIM unit which I used in EET school, when I
learned machine code.

Tom
 
R

Rich Grise

Jan 1, 1970
0
Tom said:
That was the heart of the KIM unit which I used in EET school, when I
learned machine code.

Tom

My Gawd! You people are children! The machine I first learned machine
language on had t00bZ!

Cheers!
Rich
 
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