/
/> I ought to have pointed out that most times doing what i do wastes a
> little time, and in fact it owuld heen fine just to plug the board in and
> power up. But this is amply compensted for by the time saved when thigns
> go very wrong.
Yeah and when you've gone through all the steps, learned what all the chips
are for, plugged them in one by one and finally the whole thing does actually
work, the satisfaction is much bigger.
> Do I conclude from this that the first byte read --- in fact all bytes
> read -- are always 0?
Exactly. And I just figured that they all are framing errors. Here's my test
program that should exit when it reads a byte that has no framing error:
LDAA #%00010000 ; like in jbug (8bit, np, 2stop, no divide)
STAA $8008 ; acia control reg
READ LDAA $8008 ; acia status reg
ASRA
BCC READ ; branch unless data ready
BITA #%00001000 ; check framing error
BNE READ ; branch if framing error
SWI
It never exists no matter what audio file. The only thing that does work is
that the data ready bit stays cleared as long as there is no audio at all.
So it at least reacts to the fact that there is audio or not.
> I assume this ACIA is a 6850. What does the data input do when you play
> the audio file? Where does the Rx Clock signal come from, and is it correct?
Yes, it's a 6850. I measured with a volt meter, I don't have a scope (yet).
RxD and RxC are high when no audio and they both drop to around 2V when audio is
supplied, so I guess there's at least some signal. Also RTS is low as it should.
Something weird that I don't understand is that simply adjusting the audio volume,
the apparent voltage measured on the RxD changes more or less proportionally...
this is supposed to be digital and FM ?
Wim.
Dave writes:
> On 11/22/10 4:12 PM, Tony Duell wrote:
>>> I have a S100 board that is said to be a math processor board
>>> that has a single 2901 on it. I have the manual as well.
>>
>> I find that strange. A single 4 bit slice is not that useful. I asusme
>> there arten;t 2903s as well :-)
> Well, 2901s were fairly expensive chips in those days, and it's
> certainly possible to do wider-than-four-bit math in a four-bit CPU. :)
>> Althoguh AFAIK DEC never used them in a PDP11 CPU. There were, of
>> course, used i nteh floating point processors for some PDP11s, and in the
>> VAX11/730
> And the KS10 as well. I wonder if there are any others; I don't
> think so offhand.
> One of my favorite uses of Am2901s is in the FPF11 floating-point
> processor. For the non-PDP11-savvy, the FPF11 is a strange board that
> can be used in both Qbus and Unibus systems by changing jumpers near the
> card-edge connectors. It uses a 40-pin ribbon cable to plug into a
> microm DIP socket in an F11-based PDP-11 (11/23 or 11/24).
Off the top of my head... DEC also has 2901's in the CI780, and the UDA50, and probably
A bunch of other peripherals/interconnects/host adapters I cannot recall at the moment.
Tim.
A while back, part of an AMD 2900 development
system showed up on eBay. My copies of the software
surfaced today, so the .imd images are up under
http://bitsavers.org/bits/AMD
They are CP/M 1.4, as I recall.
Hi all,
I suspect some folk here have done this before.... :-)
My desktop CRT (over 10 years, but not what I'd consider vintage!) has been
ailing for some time, with the picture getting darker and darker despite
having the brightness at 100%. It's still good for high-contrast stuff such as
black text on white background, but forget trying to pull details out of most
photos, for instance.
Heater voltage seems good at 6.4VDC / 350mA (it's derived from the PSU in this
monitor rather than the flyback section), but I'm considering boosting it a
little and see if it improves things, obviously shortening the life of the
tube in the process.
Question is, what's a sensible amount to over-run things by? Say I aimed for
around 10%, is that too much and going to kill the heaters in next to no time,
or so little that unlikely to really make any useful difference?
cheers
Jules
>Message: 14
>Date: Mon, 22 Nov 2010 15:41:05 -0800 (PST)
>From: Fred Cisin <cisin at xenosoft.com>
>Subject: RE: possible ic source
>
>On Mon, 22 Nov 2010, John Foust wrote:
>> Even today, Google Maps says the difference in Chicago's favor is
>> 13 hours 9 minutes versus 13 hours 32 minutes, but I bet you can drive
>> at a higher speed from El Paso than you can from Chicago.
>
>In the mid 20th century, Texans would brag, "You can ride a train all day
>and still be in Texas"
>Pennsylvania: We used to have a slow train, also.
>Alaska (1958): ?Quit bragging, or we'll cut Alaska in half, and then Texas
>will be the THIRD largest state.
>
There is a story I have heard that there was a WWII POW camp in Texas?for captured German pilots. The captured pilots were trucked from the ship in port to the camp. ?They thought that they were being driven around in circles to break them, because they could not believe that someone could drive so long and still be in the same country, let alone state.
Bob
Hallo
Do you have HP64000 5 1/4 diskettes with Assembler / Lindker 6809 and
also Emulator software 6809 ?
Do you send such dikettes ?
I there any other way to get HP64000 compatible disks ?
thanks in advance
schoch alfred
medatec austria
/
/> I ought to have pointed out that most times doing what i do wastes a
> little time, and in fact it owuld heen fine just to plug the board in and
> power up. But this is amply compensted for by the time saved when thigns
> go very wrong.
Yeah and when you've gone through all the steps, learned what all the chips
are for, plugged them in one by one and finally the whole thing does actually
work, the satisfaction is much bigger.
> Do I conclude from this that the first byte read --- in fact all bytes
> read -- are always 0?
Exactly. And I just figured that they all are framing errors. Here's my test
program that should exit when it reads a byte that has no framing error:
LDAA #%00010000 ; like in jbug (8bit, np, 2stop, no divide)
STAA $8008 ; acia control reg
READ LDAA $8008 ; acia status reg
ASRA
BCC READ ; branch unless data ready
BITA #%00001000 ; check framing error
BNE READ ; branch if framing error
SWI
It never exists no matter what audio file. The only thing that does work is
that the data ready bit stays cleared as long as there is no audio at all.
So it at least reacts to the fact that there is audio or not.
> I assume this ACIA is a 6850. What does the data input do when you play
> the audio file? Where does the Rx Clock signal come from, and is it correct?
Yes, it's a 6850. I measured with a volt meter, I don't have a scope (yet).
RxD and RxC are high when no audio and they both drop to around 2V when audio is
supplied, so I guess there's at least some signal. Also RTS is low as it should.
Something weird that I don't understand is that simply adjusting the audio volume,
the apparent voltage measured on the RxD changes more or less proportionally...
this is supposed to be digital and FM ?
Wim.
