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General => General Chat => Topic started by: rexxar on May 13, 2015, 03:49:05 am

Title: Worst datasheet I've ever seen
Post by: rexxar on May 13, 2015, 03:49:05 am
Just look at this mess, it's like it was thrown together by an unpaid child intern at 4:45 on their last day. link (http://www.mouser.com/ds/2/470/rfd22301.data.sheet.11.24.13_11.38pm-272240.pdf)

The electrical specifications are okay, but it doesn't show peak current draw. Want to know where that figure is? It's 4 pages down in the section about using coin cell batteries. WTF, that's an important spec! Put it in the table with everything else!  :wtf: I looked at this datasheet forever just trying to figure out if I need local bypassing. Again it's in the battery section. WHY?!

There's also no information at all about protocols or software, other than "Oh, just use Arduino!". What does the "factory" pin do? Who knows, it's a mystery! At least they included all their FCC certifications. The last half of the document is possible board layout examples. A lot of them seem redundant, and are arranged almost at random. Whoever laid this out was very fond of primary colors.

At first I thought this was some sort of wanky "datasheet" that adafruit and the like have, with just enough information for a user to get started. But no, this datasheet is also what Mouser gives you, it seems that this is the official datasheet. I especially like that they shoved two pages of advertising there in the middle.
Title: Re: Worst datasheet I've ever seen
Post by: Fsck on May 13, 2015, 03:56:12 am
the advertising is the best touch. I don't mind the colours, at least they're high contrast so the point is clear.

the datasheet would make me avoid their company like the plague though.
Title: Re: Worst datasheet I've ever seen
Post by: T3sl4co1l on May 13, 2015, 04:05:27 am
"Transmit Current 12mA"

Seems fairly straightforward to me.  Most of the table looks like it's cribbed from the ARM datasheet (stuff like RC oscillator, SPI timing, etc.), which shouldn't be a surprise; they likely have done little to nothing "new", just packaged a chip someone else made.

For power supply purposes, you can reasonably suppose it'll draw no more than twice that (i.e., 24mA), and have plenty of capacity to spare for whatever else you might plug in.  Making similar allowances there too, of course.

I'm convinced *all* IoT devices are crap, so don't be surprised.

The most important thing to remember about all embedded circuitry: even if it looks like some hard coded module, chances are, there's code inside.  And their code is shit.  Software is one thing you can count on being bad; good, solid, bug-free code is the exception, not the rule.

I'm especially puzzled by the manufacturer's use of the F-22 Raptor's visage on their front page; are they suggesting that their products are used in defense applications as well?  (If so, where are their certifications?)  God help us.

Tim
Title: Re: Worst datasheet I've ever seen
Post by: amyk on May 13, 2015, 04:23:38 am
That's less of a datasheet and more of an advert...

Look up FCC's certification info on their ID and you get a nice "internal picture" which shows they are just a packaged nRF51822. Google the latter to find some more documentation... the funny thing is, the nRF51 full manual is a smaller file than that "datasheet"!
Title: Re: Worst datasheet I've ever seen
Post by: Len on May 13, 2015, 05:33:29 am
I'm especially puzzled by the manufacturer's use of the F-22 Raptor's visage on their front page; are they suggesting that their products are used in defense applications as well?  (If so, where are their certifications?)  God help us.

That's an F-15 not an F-22. So, 40-year-old technology. :)
Title: Re: Worst datasheet I've ever seen
Post by: T3sl4co1l on May 13, 2015, 05:59:11 am
Gah!  The vertical fins threw me for a loop.  I need to read up on my fighter jets  :-[
Title: Re: Worst datasheet I've ever seen
Post by: jt on May 17, 2015, 03:49:28 am
Funny coincidence; I was just looking at this module from its use on this open EEG platform:
http://www.openbci.com/ (http://www.openbci.com/)

Doing some research, it does seem like there is a decent community following for it (see below).  Maybe that helps offset datasheet deficiencies. 
http://forum.rfduino.com/index.php?PHPSESSID=v1qog45c0bf2n9v76gbnn18657& (http://forum.rfduino.com/index.php?PHPSESSID=v1qog45c0bf2n9v76gbnn18657&)

I'm hoping it could be used as a simple wireless UART bridge for wireless terminal access without causing headaches.
Title: Re: Worst datasheet I've ever seen
Post by: andersm on May 17, 2015, 12:59:08 pm
What does the "factory" pin do? Who knows, it's a mystery!
It's hardly unusual for devices to have marked test mode pins, though the datasheets usually tell you to leave them unconnected.
Title: Re: Worst datasheet I've ever seen
Post by: calexanian on May 18, 2015, 02:04:16 am
Not the best looking datasheet for sure. Looks like it was made with old freeware cad software.
Title: Re: Worst datasheet I've ever seen
Post by: VK3DRB on May 18, 2015, 10:21:37 am
Sounds like they might just buy them in from China.

As far as component datasheets go:

Worst is stuff out of the People's Republic of China. It appears there is always important information missing from their datasheets. With programmer's reference data, forget it.

Best is Scandinavian and American devices... usually always very informative, detailed and useful. And if there are protocols or software commands, you get the full story. I personally think both Atmel and Microchip do a wonderful job with their datasheets. Sure, they are several hundred pages long, but it is pretty much all there.  Rarely does one even find a mistake in them, but always read the errata!.

Bottom line... you get what you pay for.
Title: Re: Worst datasheet I've ever seen
Post by: Psi on May 18, 2015, 10:25:23 am
You know things are going to be bad when the datasheet contains an Arduino screenshot
Title: Re: Worst datasheet I've ever seen
Post by: rob77 on May 18, 2015, 12:34:15 pm
You know things are going to be bad when the datasheet contains an Arduino screenshot

exactly ! ;) but on the other hand the datasheet is adequate for that product and it's targeted audience.  >:D