On Thu, 15 Dec 2016 12:17:30 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>On 12/15/2016 04:11 PM, John Larkin wrote:
>> On Thu, 15 Dec 2016 11:55:29 -0800 (PST), koder
>> <ptmisiewicz@gmail.com> wrote:
>>
>>> jmariano, could you upload your corrected SPI and AD`s library?
>>
>> The SPI interface of AD7793 is hopelessly trashed. Use ADS1247.
>>
>>
>
>I notice that you're piling in the extra chromosomes there. Kudos.
>
>Cheers
>
>Phil Hobbs
If there are enough bad google links, maybe they will actually fix the
stupid part.
(But we know they won't.)
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by John Larkin●December 15, 20162016-12-15
On Thu, 15 Dec 2016 11:55:29 -0800 (PST), koder
<ptmisiewicz@gmail.com> wrote:
>jmariano, could you upload your corrected SPI and AD`s library?
The SPI interface of AD7793 is hopelessly trashed. Use ADS1247.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Reply by koder●December 15, 20162016-12-15
jmariano, could you upload your corrected SPI and AD`s library?
Reply by Steve Goldstein●July 26, 20142014-07-26
On Sat, 26 Jul 2014 07:20:49 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
...snippage...
>
>112 pages is impressive, but it suggests that the part is very complex. In some
>mixed-signal parts, like ADCs, they are way too complex. I don't need an ADC to
>have a complex internal calibration subsystem; I will do calibrations in the uP
>or FPGA. It's crazy to have a DAC that has pages and pages of (typically
>confusing) documentation about dozens of internal registers.
Yes, it is a complex part, two chips in a single package that play as
one from the customer's view. Both die are accessible via the
(single) SPI, and there is situation-dependent information exchange
between them. There are no ADCs, but a lot of interesting pure-analog
functionality, quite a few DACs, and registers and state machines to
control it all. The die are not small.
Often nowadays you _do_ need an ADC to have a complex internal
calibration subsystem, though you may not realize it. Modern ADC
architectures, especially those using fine-line processes, are often
not even usable without a lot of internal self-calibration. This
requires intimate knowledge of their powerful internal magic that the
manufacturers are not about to divulge. Fortunately, transistors in
these processes are small and cheap, so the cal engine can be put
on-chip. Given everything else the cal machine does, the incremental
cost of gain and offset calibration is often trivial. Of course, such
calibration often only takes care of the ADC errors alone and you're
still left with the rest of the signal channel to worry about, so I
can understand why you don't value the cal engine very highly.
As far as DACs and other things with a bazillion registers, the
economics of chip design and manufacturing often come into play. You
want to make a few parts that will capture as many sockets as
possible; development cost is now too high to do otherwise. I agree
the manufacturers certainly could spend a little more time and money
(a pittance in the grand scheme of things) to de-confuse datasheets
and make them actually useful. This has been my personal crusade
since I first got hosed by a datasheet back around 1985. You can bet
that the datasheets for my parts are as clear, accurate, and
well-written as I can make them, whether I do the actual writing or,
more usually, a significant amount of rewriting. It's what I would
expect if I were the customer.
Reply by Tim Williams●July 26, 20142014-07-26
"rickman" <gnuarm@gmail.com> wrote in message
news:lr1dl7$emv$1@dont-email.me...
> The point is that you turn your head one way to read the dimensions and
> turn your head the other way to read the labels. The convention is to
> turn the text counter clock wise or not at all, not to turn anything
> clockwise. Some times this happens because an image is drawn the
> correct way but then rotated to fit on the page better. The choices
> then are to have some text rotated clockwise or to have some text upside
> down. I guess the clockwise text is preferred. In this case the labels
> did not need to be rotated at all. Also the dimensioning lines are not
> drawn properly... I expect this was drawn by someone inexperienced using
> conventional drawing tools.
Yes, clarity would include a leader to indicate the connection between the
number and the dimension. And calling it "5.0" would be even better --
makes it obvious it's not a pin number or something.
I don't actually mind the colors, but the traditional complaint would be,
they won't always come through e.g. on photocopies (yes, those things
still exist). If it's clear in monochrome, you don't have to worry about
anything else.
Tim
--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com
><krw@attt.bizz> wrote in message
>news:fjp7t956dub6gpciinaromqocihvc0borq@4ax.com...
>> If you think that's bad, try their RF chips. They intentionally hide
>> the innards so they have to do pretty much everything. TI has been
>> known to have undocumented registers, too. The designers don't even
>> know what they do ("try all the combinations").
>
>Most people boggle their mind over the NSA/GHCQ's demilling of The
>Guardian's laptops (the ones they had Snowden docs on), the obscure chips
>they ground away -- PSU controllers and stuff.
>
>Doesn't seem strange to me. Many of those have low-functionality
>registers (i.e., poking bits into them doesn't put 5V on the CPU core or
>something drastic like that), that are easily acessible (via SMBus, etc.),
>which could be used to store information in a somewhat obscure way. Not
>much of course, but enough for a key at least. And taken over the whole
>system, probably enough for a message.
>
>As for undocumented registers, certainly there are things the
>manufacturers put in there for their own purposes; whether they're locked,
>invisible, functional or what, who knows; but it's likely the NSA has some
>ideas.
Undocumented, sure. We had registers the users knew nothing about but
none were user accessible. That's not what I was talking about,
though.
>Easily possible the NSA even has them synthesizing extra bits, or
>allocating otherwise-unused corners of array memory, for clandestine
>purposes.
>
>Even if they don't have design information from the manufacturer (or from
>decapping and inspecting the chip), it's probably enough that it's a
>possibility, even if they don't have it as a capability.
>
>As for destruction, even if the registers are SRAM or DRAM, they can
>retain info between power cycles, so they might go out of their way to
>destroy anything stateful, just in case.
All completely irrelevant.
Reply by rickman●July 26, 20142014-07-26
On 7/26/2014 6:18 PM, Jasen Betts wrote:
> On 2014-07-26, Tim Williams <tmoranwms@charter.net> wrote:
>> <krw@attt.bizz> wrote in message
>> news:lfb7t9pd3f0mldv7kladtoel4nbjm5n6cr@4ax.com...
>>> Anyone else notice that Asian and European datasheets are particularly
>>> bad? Content free. It's not just the translation (but that's a part
>>> of it).
>>
>> Here's an amusing example I ran across recently:
>> http://www.adafruit.com/datasheets/WS2812B.pdf
>> Note the power supply voltage: remind you of a certain Sandra Bullock
>> movie? What happens when it drops below ...
>>
>> The formatting is just janky, clearly a novice writing in Word.
>
>
>> The mech / layout drawings have text going every which way; the "VDD 5
>> DOUT" with the 5 backwards, especially.
>>
>> Good luck with those timings.
>
> "VDD DOUT" are pin labels "5" is a dimension (5mm)
The point is that you turn your head one way to read the dimensions and
turn your head the other way to read the labels. The convention is to
turn the text counter clock wise or not at all, not to turn anything
clockwise. Some times this happens because an image is drawn the
correct way but then rotated to fit on the page better. The choices
then are to have some text rotated clockwise or to have some text upside
down. I guess the clockwise text is preferred. In this case the labels
did not need to be rotated at all. Also the dimensioning lines are not
drawn properly... I expect this was drawn by someone inexperienced using
conventional drawing tools.
--
Rick
Reply by Jasen Betts●July 26, 20142014-07-26
On 2014-07-26, Tim Williams <tmoranwms@charter.net> wrote:
><krw@attt.bizz> wrote in message
> news:lfb7t9pd3f0mldv7kladtoel4nbjm5n6cr@4ax.com...
>> Anyone else notice that Asian and European datasheets are particularly
>> bad? Content free. It's not just the translation (but that's a part
>> of it).
>
> Here's an amusing example I ran across recently:
> http://www.adafruit.com/datasheets/WS2812B.pdf
> Note the power supply voltage: remind you of a certain Sandra Bullock
> movie? What happens when it drops below ...
>
> The formatting is just janky, clearly a novice writing in Word.
> The mech / layout drawings have text going every which way; the "VDD 5
> DOUT" with the 5 backwards, especially.
>
> Good luck with those timings.
"VDD DOUT" are pin labels "5" is a dimension (5mm)
--
umop apisdn
--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Reply by rickman●July 26, 20142014-07-26
On 7/26/2014 9:40 AM, krw@attt.bizz wrote:
> On Sat, 26 Jul 2014 09:11:30 -0400, Steve Goldstein
>
>> Writing a good datasheet is surprisingly hard work. It's a pity that
>> more companies (and engineers) don't recognize the importance of the
>> task and treat it with the respect it deserves.
>
> Apparently, it's often done after the part is cooked. That never
> works out.
>
> Anyone else notice that Asian and European datasheets are particularly
> bad? Content free. It's not just the translation (but that's a part
> of it).
I was working with one of the Atmel MCUs and realized they had no spec
on the crystal. So I had nothing to provide to the crystal company to
make sure I got a crystal that would work. I asked the FAE for info on
this and it ended up with some data added to the data sheet. However,
they gave the info for four specific frequencies in the range without
specifying which values should be used between those frequencies. lol
Once they made a change to the data sheet, I guess it was enough work
that they weren't going to fill in the blanks. They probably have to go
through a review process that means a 5 minute change to the document
takes many man hours of work.
--
Rick
Reply by Tim Williams●July 26, 20142014-07-26
<krw@attt.bizz> wrote in message
news:fjp7t956dub6gpciinaromqocihvc0borq@4ax.com...
> If you think that's bad, try their RF chips. They intentionally hide
> the innards so they have to do pretty much everything. TI has been
> known to have undocumented registers, too. The designers don't even
> know what they do ("try all the combinations").
Most people boggle their mind over the NSA/GHCQ's demilling of The
Guardian's laptops (the ones they had Snowden docs on), the obscure chips
they ground away -- PSU controllers and stuff.
Doesn't seem strange to me. Many of those have low-functionality
registers (i.e., poking bits into them doesn't put 5V on the CPU core or
something drastic like that), that are easily acessible (via SMBus, etc.),
which could be used to store information in a somewhat obscure way. Not
much of course, but enough for a key at least. And taken over the whole
system, probably enough for a message.
As for undocumented registers, certainly there are things the
manufacturers put in there for their own purposes; whether they're locked,
invisible, functional or what, who knows; but it's likely the NSA has some
ideas.
Easily possible the NSA even has them synthesizing extra bits, or
allocating otherwise-unused corners of array memory, for clandestine
purposes.
Even if they don't have design information from the manufacturer (or from
decapping and inspecting the chip), it's probably enough that it's a
possibility, even if they don't have it as a capability.
As for destruction, even if the registers are SRAM or DRAM, they can
retain info between power cycles, so they might go out of their way to
destroy anything stateful, just in case.
Tim
--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com