Low-cost low-pin count MCU with USB Host support

marți, 14 iunie 2016, 23:19:02 UTC+3, rickman a scris:
> On 6/14/2016 2:09 PM, Simon Clubley wrote:
> > On 2016-06-14, Espo <spam@spam.com> wrote:
> >> Xmega is interesting too, and cheaper than SAM.
> >> 8 bit CPU, but rich and powerful peripherals.  I've been using it
> >>  recently and it's quite nice.
> >>
> >> By the way, just a quick warning: "Full speed" USB2.0 is not
> >>  actually full speed but only 12Mbps.  I got caught out by this at
> >>  first.
> >
> > Yes, that can be confusing if you are not used to the fact the USB
> > standards group redefined the meaning of the word "full" in the
> > presence of 480Mbps USB. When the latter came along they called it
> > high speed USB and kept the full speed description for 12Mbps USB.
> >
> > I remember comments at the time saying people would find it confusing.
> 
> Yeah, I found it confusing.  But it is a name and names are not always 
> descriptive.  It would have been more confusing if they called 480 Mbps 
> "full" speed.  I suppose they could have given it some other name like 
> "not quite full speed" or "a bit less than full speed".  ;-)
> 
> -- 
> 
> Rick C

I don't know why it is confusing.
"Full speed" always refers to 12Mbps.
"High speed" always refers to 480Mbps.
It's quite clear, noone says full speed to 480Mbps, or high speed to 12Mbps.
Maybe "USB2.0" is confusing, because sometimes a manufacturer doesn't
support high speed, only full speed, but it may still say "USB2.0".
However, they specify the max. speed, for example "USB2.0 full speed" :)

On 2016-06-15, raimond.dragomir@gmail.com <raimond.dragomir@gmail.com> wrote:
>
> I don't know why it is confusing.

It was more confusing when high speed USB was new to people because
people unfamiliar with the history of USB might think "full speed"
meant they were getting a top of the line product when it came to speed.

IOW, in those days, then they saw a product described as "full speed",
did they think they were getting a 480Mbps product or a 12Mbps product ?

Simon.

-- 
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world

On 2016-06-15, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
> On 2016-06-15, raimond.dragomir@gmail.com <raimond.dragomir@gmail.com> wrote:
>>
>> I don't know why it is confusing.
>
> It was more confusing when high speed USB was new to people because
> people unfamiliar with the history of USB might think "full speed"
> meant they were getting a top of the line product when it came to speed.
>
> IOW, in those days, then they saw a product described as "full speed",
> did they think they were getting a 480Mbps product or a 12Mbps product ?

Yup.  Great scam. Truley a triumph of marketing over the forces of
truth and honesty.  There are, what, 4 different speeds of USB? And
"full speed" is second slowest?

-- 
Grant Edwards               grant.b.edwards        Yow! I have seen these EGG
                                  at               EXTENDERS in my Supermarket
                              gmail.com            ... I have read the
                                                   INSTRUCTIONS ...

> Yup.  Great scam. Truley a triumph of marketing over the forces of
> truth and honesty.  There are, what, 4 different speeds of USB? And
> "full speed" is second slowest?
> 
Do you think so? I may say it's technology advancing. With backward 
compatibilities. I am, for example, very happy that my USBASP dongle
(a "low speed" 1.5Mbps) still works, even on USB3.0 ports...

On 6/15/2016 7:19 AM, raimond.dragomir@gmail.com wrote:
> marți, 14 iunie 2016, 23:19:02 UTC+3, rickman a scris:
>> On 6/14/2016 2:09 PM, Simon Clubley wrote:
>>> On 2016-06-14, Espo <spam@spam.com> wrote:
>>>> Xmega is interesting too, and cheaper than SAM.
>>>> 8 bit CPU, but rich and powerful peripherals.  I've been using it
>>>>  recently and it's quite nice.
>>>>
>>>> By the way, just a quick warning: "Full speed" USB2.0 is not
>>>>  actually full speed but only 12Mbps.  I got caught out by this at
>>>>  first.
>>>
>>> Yes, that can be confusing if you are not used to the fact the USB
>>> standards group redefined the meaning of the word "full" in the
>>> presence of 480Mbps USB. When the latter came along they called it
>>> high speed USB and kept the full speed description for 12Mbps USB.
>>>
>>> I remember comments at the time saying people would find it confusing.
>>
>> Yeah, I found it confusing.  But it is a name and names are not always
>> descriptive.  It would have been more confusing if they called 480 Mbps
>> "full" speed.  I suppose they could have given it some other name like
>> "not quite full speed" or "a bit less than full speed".  ;-)
>>
>> --
>>
>> Rick C
>
> I don't know why it is confusing.
> "Full speed" always refers to 12Mbps.
> "High speed" always refers to 480Mbps.
> It's quite clear, noone says full speed to 480Mbps, or high speed to 12Mbps..
> Maybe "USB2.0" is confusing, because sometimes a manufacturer doesn't
> support high speed, only full speed, but it may still say "USB2.0".
> However, they specify the max. speed, for example "USB2.0 full speed" :)

I was referring to when 2.0 came out.  Calling the mid speed "full 
speed" is of course confusing if you take the term at all at its face 
value.

-- 

Rick C

On Wed, 15 Jun 2016 13:24:22 +0000 (UTC), Grant Edwards
<invalid@invalid.invalid> wrote:

>On 2016-06-15, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
>> On 2016-06-15, raimond.dragomir@gmail.com <raimond.dragomir@gmail.com> wrote:
>>>
>>> I don't know why it is confusing.
>>
>> It was more confusing when high speed USB was new to people because
>> people unfamiliar with the history of USB might think "full speed"
>> meant they were getting a top of the line product when it came to speed.
>>
>> IOW, in those days, then they saw a product described as "full speed",
>> did they think they were getting a 480Mbps product or a 12Mbps product ?
>
>Yup.  Great scam. Truley a triumph of marketing over the forces of
>truth and honesty.  There are, what, 4 different speeds of USB? And
>"full speed" is second slowest?


Arguably they should have picked better names for low-speed (1.5mbps)
and full-speed (12mbps) for USB 1.0, but given that the names existed,
and were in very widespread use when USB 2.0 became a thing, what
could you do?  Depreciate the name on most of the gear out there?
Redefine it?  Those don't really sound like more palatable choices.

On 2016-06-15, Robert Wessel <robertwessel2@yahoo.com> wrote:
> On Wed, 15 Jun 2016 13:24:22 +0000 (UTC), Grant Edwards
>>
>>> IOW, in those days, then they saw a product described as "full
>>> speed", did they think they were getting a 480Mbps product or a
>>> 12Mbps product ?

They thought they were getting the fastest speed available.

>>Yup.  Great scam. Truly a triumph of marketing over the forces of
>>truth and honesty.  There are, what, 4 different speeds of USB? And
>>"full speed" is second slowest?
>
> Arguably they should have picked better names for low-speed
> (1.5mbps) and full-speed (12mbps) for USB 1.0,

Well, I would have chosen "1.5 meg" and "12 meg".  But that's just me
be silly.

> but given that the names existed, and were in very widespread use
> when USB 2.0 became a thing, what could you do?

I know: I shouldn't attribute to malice that which can be explained by
stupidity and incomptetence. It's just a happy coincidence that the
stupid mistake turned out so that it fooled 99% of the population into
thinking old, slow junk was top-of-the line gear.

--
Grant

On Thu, 16 Jun 2016 04:59:40 +0000 (UTC), Grant Edwards
<invalid@invalid.invalid> wrote:

>On 2016-06-15, Robert Wessel <robertwessel2@yahoo.com> wrote:
>> On Wed, 15 Jun 2016 13:24:22 +0000 (UTC), Grant Edwards
>>>
>>>> IOW, in those days, then they saw a product described as "full
>>>> speed", did they think they were getting a 480Mbps product or a
>>>> 12Mbps product ?
>
>They thought they were getting the fastest speed available.
>
>>>Yup.  Great scam. Truly a triumph of marketing over the forces of
>>>truth and honesty.  There are, what, 4 different speeds of USB? And
>>>"full speed" is second slowest?
>>
>> Arguably they should have picked better names for low-speed
>> (1.5mbps) and full-speed (12mbps) for USB 1.0,
>
>Well, I would have chosen "1.5 meg" and "12 meg".  But that's just me
>be silly.


Probably my first choice too, but probably hard to get past marketing.
OTOH, that's not without its own problems.  First "1.5", "12", "480",
"5" and "10" makes for a pretty ugly set of names, and second, it's
hardly as future proof as you'd like.  Consider Ethernet, which
basically does follow that naming scheme (ignoring the plethora of
PHYs at each speed), plenty of 10Gb Ethernet cannot connect at 100Mb,
so if you happen to plug a fast Ethernet device into a 10GBb port, you
going to get a 10Mb connection (at best).  Try to condense that into a
simple label...

Devices that draw relatively large amounts of power from USB make even
more of a mess.

And trying to simplify things too much, or at least to the point where
many of your users will understand it is a common problem.

I was helping someone buy an air compressor a couple of weeks ago.
Air-powered tools have two parameters for the compressed air source -
a required pressure, and a required volume of (compressed) air
(usually PSI and SCFM in the US).  Likewise most compressors also have
those two ratings, usually at several different points (5.0scfm at
40psi, 3.0scfm at 90psi).  Pressures is usually not an issue, but the
SCFM rating is a long-standing bafflement to many people, especially
seeing as it varies with the output pressure on most compressors.  So
I've started seeing people selling air tools with a "rating" related
to the size of the compressor's tank - IOW, "needs 10 gallon
compressor".  (And yes, I know that a large tank may permit
intermittent operation, even if the compressor does not produce enough
air for continuous operations).  Worse they've simultaneously started
hiding the "real" ratings...  Grrrr...

I can sympathize with the manufacturers - they're not wanting people
to buy tools that won't work, but there doesn't appear to be a simple
(enough) way to communicate the requirements, that remains reasonably
accurate.


>> but given that the names existed, and were in very widespread use
>> when USB 2.0 became a thing, what could you do?
>
>I know: I shouldn't attribute to malice that which can be explained by
>stupidity and incomptetence. It's just a happy coincidence that the
>stupid mistake turned out so that it fooled 99% of the population into
>thinking old, slow junk was top-of-the line gear.


I don't think the problem was nearly that bad, 95% can barely find the
letters "USB" on the packaging.

On 17/06/16 02:27, Robert Wessel wrote:
> On Thu, 16 Jun 2016 04:59:40 +0000 (UTC), Grant Edwards
> <invalid@invalid.invalid> wrote:
>> Well, I would have chosen "1.5 meg" and "12 meg".  But that's just me
>> be silly.

Was another name even needed? They're already called USB 1, 2, 3, so why 
not just refer to the speed by the standard version that introduced it?

> I was helping someone buy an air compressor a couple of weeks ago.
> Air-powered tools have two parameters for the compressed air source -
> a required pressure, and a required volume of (compressed) air
> (usually PSI and SCFM in the US).

Yep, that is dopey. Should be power (watts) at pressure, for continuous 
use, since that reflects the actual requirement.

> I can sympathize with the manufacturers - they're not wanting people
> to buy tools that won't work, but there doesn't appear to be a simple
> (enough) way to communicate the requirements, that remains reasonably
> accurate.

Clifford Heath

On 6/16/2016 7:14 PM, Clifford Heath wrote:
> On 17/06/16 02:27, Robert Wessel wrote:
>> On Thu, 16 Jun 2016 04:59:40 +0000 (UTC), Grant Edwards
>> <invalid@invalid.invalid> wrote:
>>> Well, I would have chosen "1.5 meg" and "12 meg".  But that's just me
>>> be silly.
>
> Was another name even needed? They're already called USB 1, 2, 3, so why
> not just refer to the speed by the standard version that introduced it?

That is a problem we still have.  Saying a device supports USB 2.0 does 
not mean 480 Mbps.  It may be 12 Mbps or even 1.5 Mbps.  Each revision 
of the standard provides for multiple speeds which each have names.


>> I was helping someone buy an air compressor a couple of weeks ago.
>> Air-powered tools have two parameters for the compressed air source -
>> a required pressure, and a required volume of (compressed) air
>> (usually PSI and SCFM in the US).
>
> Yep, that is dopey. Should be power (watts) at pressure, for continuous
> use, since that reflects the actual requirement.

Except if you are building and using these things you can measure PSI 
and perhaps airflow, it's harder to measure the output in watts.


>> I can sympathize with the manufacturers - they're not wanting people
>> to buy tools that won't work, but there doesn't appear to be a simple
>> (enough) way to communicate the requirements, that remains reasonably
>> accurate.
>
> Clifford Heath
>


-- 

Rick C