> On Mon, 15 Jan 2018 16:22:19 -0800 (PST), tedj121@gmail.com wrote:
>
>>> http://www.ti.com/lit/ds/symlink/sn74lvc1g86.pdf
>>
>> I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
>
> There are a number of us who do prototype stuff with SMT parts.
I'd say nearly all of us.
> ... John
> Larkin has shown a lot of examples of the "dead bug" school of
> prototyping. You really should get the proper tools and leave
> thru-hole behind. You're really limiting yourself - thru-hole is
> dead.
>
Absolutamente. Ted would be missing out on most of the good stuff these
days. I adopted SMT in 1986 and never looked back. It's actually easier
to hand-solder than through-hole, no constant turning around of the
board, nothing falls back out because the wires weren't bent sideways
enough. Another nice thing is that resistors and capacitors can be
stacked for trimming experiments or when the correct value is not at hand.
Ted: You can get what is often called "surfboards" that adapt SMT to
through-hole. You could also just use those "copper-striped" boards and
cut or score out a center line in each strip which would give you the
0.05" spaing of SO packages. It's easy once you get the hang of it. For
soldering fine stuff the ETS tip for Weller irons works great.
Horror story that really happened: A friend was soldering a digital
through-hole board, didn't immediately notice that one IC had slipped
out when turning the board, the phone rang, he got up, pushing himself
off the table with one hand .... YOOOUUUWWEEE ... all IC pins were
solidly embedded in his palm. He had sort of a DIP-16 tattoo for a long
time.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by Joerg●January 16, 20182018-01-16
On 2018-01-15 22:02, rickman wrote:
> tedj121@gmail.com wrote on 1/15/2018 7:01 PM:
>>> A simple approach is to use a FF to hold a state set by the MCU and
>>> the XOR
>>> to detect edges on the incoming pulse. The pulse edge rises, the XOR
>>> wakes
>>> the CPU, the CPU changes the FF and the wakeup pulse ends. In
>>> essence the
>>> CPU becomes your delay element.
>>
>> I like the idea. No RC. Just an XOR. The CPU is powered exactly as
>> long as it needs to be. Should work for both edges. I'll try it with
>> some of those 'extra' XOR gates. :-) Ted
>
> Unless your MCU can remember and hold an output pin when powered down
> (not entirely unlikely) you will need some FF external to the MCU in
> addition to the XOR.
>
>> Doesn't the CPU support a hibernate mode with wake on change for
>> certain pins? Even if it was only for one edge transition then a
>> pair of those pins and a single inverter would get you what you
>> want.
>>
>> It seems a bit brute force and crude to start up from cold every
>> time.
>
> See reply to Mike. Looking into the Enerlib library posted at the
> Arduino website. Also, I'm not locked into the Bee (hosting the
> ATMEGA168), which is for ease of development even as I see that it's
> time to choose that final uC at this stage.
I had a quick look at the ATM168 datasheet and not only does it support
several decent power saving modes it also supports interrupt on any
transition for certain pins whilst in a low power state.
You will have to write an interrupt handler but that need not be a very
complex one just something that does whatever you want to do and returns
to sleep mode again. You might need to deal with the situation where the
down transition occurs whilst you are processing the up transition or
vice-versa (but that would be a problem for a hardware one shot too).
>
>> It probably isn't worth getting average quiescent current much
>> below the self discharge rate of typical alkaline batteries (ie
>> <5uA). If you were running it off a tiny battery then it might be
>> worth trying harder.
>
> I just have this shweet touch sensor that only consumes 5nA and
> actually works (with a little shielding).
So long as you keep the overall power consumption under 5uA you will
find that in service battery life pretty much depends on ambient
temperature and how badly stored the battery was before you bought it.
--
Regards,
Martin Brown
Reply by rickman●January 16, 20182018-01-16
tedj121@gmail.com wrote on 1/15/2018 7:01 PM:
>> A simple approach is to use a FF to hold a state set by the MCU and the XOR
>> to detect edges on the incoming pulse. The pulse edge rises, the XOR wakes
>> the CPU, the CPU changes the FF and the wakeup pulse ends. In essence the
>> CPU becomes your delay element.
>
> I like the idea. No RC. Just an XOR. The CPU is powered exactly as long as it needs to be. Should work for both edges. I'll try it with some of those 'extra' XOR gates. :-) Ted
Unless your MCU can remember and hold an output pin when powered down (not
entirely unlikely) you will need some FF external to the MCU in addition to
the XOR.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
Reply by ●January 15, 20182018-01-15
On Tue, 16 Jan 2018 01:05:51 +0000, Mike Perkins <spam@spam.com>
wrote:
>On 16/01/2018 00:51, krw@notreal.com wrote:
>> On Mon, 15 Jan 2018 16:22:19 -0800 (PST), tedj121@gmail.com wrote:
>>
>>>> http://www.ti.com/lit/ds/symlink/sn74lvc1g86.pdf
>>>
>>> I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
>>
>> There are a number of us who do prototype stuff with SMT parts. John
>> Larkin has shown a lot of examples of the "dead bug" school of
>> prototyping. You really should get the proper tools and leave
>> thru-hole behind. You're really limiting yourself - thru-hole is
>> dead.
>
>Through hole still lives where you want mechanical resilience for items
>like connectors. Otherwise I entirely agree.
Oh, certainly. PTH capacitors may have lower ESL and ESR, as well. We
often use PTH capacitors, inductors, and of course, connectors.
Reply by Mike Perkins●January 15, 20182018-01-15
On 16/01/2018 00:51, krw@notreal.com wrote:
> On Mon, 15 Jan 2018 16:22:19 -0800 (PST), tedj121@gmail.com wrote:
>
>>> http://www.ti.com/lit/ds/symlink/sn74lvc1g86.pdf
>>
>> I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
>
> There are a number of us who do prototype stuff with SMT parts. John
> Larkin has shown a lot of examples of the "dead bug" school of
> prototyping. You really should get the proper tools and leave
> thru-hole behind. You're really limiting yourself - thru-hole is
> dead.
Through hole still lives where you want mechanical resilience for items
like connectors. Otherwise I entirely agree.
--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk
Reply by ●January 15, 20182018-01-15
On Mon, 15 Jan 2018 16:22:19 -0800 (PST), tedj121@gmail.com wrote:
>> http://www.ti.com/lit/ds/symlink/sn74lvc1g86.pdf
>
>I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
There are a number of us who do prototype stuff with SMT parts. John
Larkin has shown a lot of examples of the "dead bug" school of
prototyping. You really should get the proper tools and leave
thru-hole behind. You're really limiting yourself - thru-hole is
dead.
Reply by Lasse Langwadt Christensen●January 15, 20182018-01-15
Den tirsdag den 16. januar 2018 kl. 01.22.28 UTC+1 skrev ted...@gmail.com:
> > http://www.ti.com/lit/ds/symlink/sn74lvc1g86.pdf
>
> I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
I find surface mount to be easier, no messing around with constantly flipping
the board and trying to hold in parts before soldering, just align part and
tack one pin and solder
I'm drooling, but still stuck in the 'through hole' world just now until everything is proven. I'm just basement entrepreneurial with an eye toward quantity in the future. Surface mount is a challenge in development. Gotta solder those little suckers on manually. Ted
Reply by Joerg●January 15, 20182018-01-15
On 2018-01-11 10:23, tedj121@gmail.com wrote:
> Hi,
>
> I'd like to take a long input pulse and trigger a much shorter
> one-shot pulse at its rising and falling edges. Ideally, only a
> single input should be required (i.e. the one long pulse) for minimal
> part count. I've looked over several timer ics and none seem to fit
> the bill or are too pricey like the 6993s. Can anyone suggest an
> appropriate ic? I would think it a common enough function to warrant
> a dedicated chip. Thanks, Ted
>
Since price is so important you probably don't want a discrete solution
with lots of parts because of the pick & place machine charges.
Consider an external watchdog timer (WDT) chip. Often they come in the
same package with a power supply supervisor. They are cheap and used by
people (like myself) who do not trust on-chip supervisor functions on
micro controllers.
The way these work: Their output goes high for a certain time after
either a rising or falling edge on the input signal. If no such
transition occurs for a while their output goes low (meant to issue a
micro controller reset) and this time would be your one-shot pulse
length. You'd just have to pick one with the desired number of seconds.
Some also have a voltage supervisor in there which keops the outut low
until the supply is above a certain threshold. If you don't want that
use one without or one with a low enough voltage threshold.
Another method is to take the cheapest micro controller you can find and
program its internal timer so it will trigger a one-shot period after a
"state change", thus after a falling as well as a rising edge.
--
Regards, Joerg
http://www.analogconsultants.com/