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Rising and Falling Edge triggered one-shot
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ted...@gmail.com
Jan 11, 2018, 1:23:18 PM1/11/18
to
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
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
Phil Hobbs
Jan 11, 2018, 1:26:45 PM1/11/18
to
plan to use?
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
https://hobbs-eo.com
Martin Brown
Jan 11, 2018, 1:37:46 PM1/11/18
to
--
Regards,
Martin Brown
John Larkin
Jan 11, 2018, 1:51:52 PM1/11/18
to
Or even a PCB trace!
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Message has been deleted
ted...@gmail.com
Jan 11, 2018, 3:57:22 PM1/11/18
to
Hi and thanks for responding.
I have a touch sensor. Goes on when touched and off when not. I want my uC to do a service operation at each edge of that (possibly long) 'pulse'. My uC needs about a second or so from power up to the beginning of program start. The uC is energized by that sensor signal being ON. At program start it immediately asserts another bit that controls whether to continue power to itself and other circuits. So the one-shot duration is just long enough to wake up the uC, which then services the event and then goes back to sleep.
I plan to use a four cell (or possibly six) penlight pack for power. I'm hoping to tolerate battery decay to just above 3.3 volts from a max of about 6 or 9.
So the one-shots are about a second or so in duration and the spacing between the sensor signal edges is typically several seconds. Most one-shots I've found assume a trigger pulse much shorter than the one-shot itself and I need the reverse. An input that initiates an identical pulse at either edge would be ideal.
Price is a consideration - a cheap timer and few external components is a plus.
I want to implement a sleep mode whose quiescent current only powers the touch sensor (at ~ 5nA) to maximize battery life with all else being off.
Thanks, Ted
I have a touch sensor. Goes on when touched and off when not. I want my uC to do a service operation at each edge of that (possibly long) 'pulse'. My uC needs about a second or so from power up to the beginning of program start. The uC is energized by that sensor signal being ON. At program start it immediately asserts another bit that controls whether to continue power to itself and other circuits. So the one-shot duration is just long enough to wake up the uC, which then services the event and then goes back to sleep.
I plan to use a four cell (or possibly six) penlight pack for power. I'm hoping to tolerate battery decay to just above 3.3 volts from a max of about 6 or 9.
So the one-shots are about a second or so in duration and the spacing between the sensor signal edges is typically several seconds. Most one-shots I've found assume a trigger pulse much shorter than the one-shot itself and I need the reverse. An input that initiates an identical pulse at either edge would be ideal.
Price is a consideration - a cheap timer and few external components is a plus.
I want to implement a sleep mode whose quiescent current only powers the touch sensor (at ~ 5nA) to maximize battery life with all else being off.
Thanks, Ted
Message has been deleted
ted...@gmail.com
Jan 11, 2018, 4:24:12 PM1/11/18
to
Chips like:
CD4538 - https://media.digikey.com/pdf/Data%20Sheets/Fairchild%20PDFs/CD4538BC.pdf
74123 - http://www.ti.com/lit/ds/symlink/sn74lvc1g123.pdf
TPL5110 - http://www.ti.com/lit/ds/symlink/tpl5110.pdf
seem promising, but I'd like to spice test whether any can do the job but can find no models. Hoping I might happen upon a guru.
Could only find:
HC4538_JT.zip - http://www.analog-innovations.com/subcircuits.html
but it doesn't appear to work.
CD4538 - https://media.digikey.com/pdf/Data%20Sheets/Fairchild%20PDFs/CD4538BC.pdf
74123 - http://www.ti.com/lit/ds/symlink/sn74lvc1g123.pdf
TPL5110 - http://www.ti.com/lit/ds/symlink/tpl5110.pdf
seem promising, but I'd like to spice test whether any can do the job but can find no models. Hoping I might happen upon a guru.
Could only find:
HC4538_JT.zip - http://www.analog-innovations.com/subcircuits.html
but it doesn't appear to work.
mike
Jan 11, 2018, 4:25:47 PM1/11/18
to
Message has been deleted
Phil Hobbs
Jan 11, 2018, 4:48:19 PM1/11/18
to
On 01/11/2018 03:49 PM, ted...@gmail.com wrote:
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
> want my uC to do a service operation at each edge of that (possibly
> long) 'pulse'. My uC needs about a second or so from power up to the
> beginning of program start. The uC is energized by that sensor
> signal being ON, at which point it immediately asserts another bit
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
> want my uC to do a service operation at each edge of that (possibly
> long) 'pulse'. My uC needs about a second or so from power up to the
> beginning of program start. The uC is energized by that sensor
> that controls whether to continue power to itself and other circuits.
> So the one-shot duration is just long enough to wake up the uC, which
> then services the event and then goes back to sleep.
>
> I plan to use a four cell (or possibly six) penlight pack for power.
> I'm hoping to tolerate battery decay to just above 3.3 volts from a
> max of about 6 or 9.
>
> So the one-shots are about a second or so in duration and the spacing
> between the sensor signal edges is typically several seconds. Most
> one-shots I've found assume a trigger pulse much shorter than the
> one-shot itself and I need the reverse. An input that initiates an
> identical pulse at either edge would be ideal.
>
> Price is a consideration - a cheap timer and few external components
> is a plus.
>
> I want to implement a sleep mode whose quiescent current only powers
> the touch sensor (at ~ 5nA) to maximize battery life with all else
> being off.
>
> Thanks, Ted
>
> On Thursday, January 11, 2018 at 1:23:18 PM UTC-5, ted...@gmail.com
> wrote:
> So the one-shot duration is just long enough to wake up the uC, which
> then services the event and then goes back to sleep.
>
> I plan to use a four cell (or possibly six) penlight pack for power.
> I'm hoping to tolerate battery decay to just above 3.3 volts from a
> max of about 6 or 9.
>
> So the one-shots are about a second or so in duration and the spacing
> between the sensor signal edges is typically several seconds. Most
> one-shots I've found assume a trigger pulse much shorter than the
> one-shot itself and I need the reverse. An input that initiates an
> identical pulse at either edge would be ideal.
>
> Price is a consideration - a cheap timer and few external components
> is a plus.
>
> I want to implement a sleep mode whose quiescent current only powers
> the touch sensor (at ~ 5nA) to maximize battery life with all else
> being off.
>
> Thanks, Ted
>
> On Thursday, January 11, 2018 at 1:23:18 PM UTC-5, ted...@gmail.com
> wrote:
half of an MC14538A or CD14538A with the long pulse capacitively coupled
into both trigger inputs (separately). That's one chip and three RCs,
and will work over your supply range.
The CD4047 is sort of a monostable/astable toolkit, with a separate pin
to control retriggerability. Looks like you'd still need two RCs though.
But before somebody else says it, you can do all this and more with a
very small microcontroller such as an ATtiny5 (20 cents) and a
micropower voltage regulator.
mike
Jan 11, 2018, 5:25:54 PM1/11/18
to
On 1/11/2018 1:33 PM, ted...@gmail.com wrote:
> Bluetooth Bee Standalone v1
I only spent a few minutes with google, but going from
bluetooth bee to the chip specs
http://electronut.in/atmega168-power-save-mode-and-pin-change-interrupt/
I'm a PIC person, so have no direct experience here.
> Bluetooth Bee Standalone v1
I only spent a few minutes with google, but going from
bluetooth bee to the chip specs
http://electronut.in/atmega168-power-save-mode-and-pin-change-interrupt/
I'm a PIC person, so have no direct experience here.
George Herold
Jan 11, 2018, 5:55:08 PM1/11/18
to
and some RC high passes.
George H.
Jasen Betts
Jan 11, 2018, 8:01:19 PM1/11/18
to
On 2018-01-11, ted...@gmail.com <ted...@gmail.com> wrote:
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
want my uC to do a service operation at each edge of that (possibly
long) 'pulse'. My uC needs about a second or so from power up to the
beginning of program start. The uC is energized by that sensor signal
being ON. At program start it immediately asserts another bit that
controls whether to continue power to itself and other circuits. So
the one-shot duration is just long enough to wake up the uC, which
then services the event and then goes back to sleep.
how much of that interconection is non-negotiable?
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
want my uC to do a service operation at each edge of that (possibly
long) 'pulse'. My uC needs about a second or so from power up to the
beginning of program start. The uC is energized by that sensor signal
being ON. At program start it immediately asserts another bit that
controls whether to continue power to itself and other circuits. So
the one-shot duration is just long enough to wake up the uC, which
then services the event and then goes back to sleep.
why do you need the one-shot when the sensor turns on?
> So the one-shots are about a second or so in duration and the
> spacing between the sensor signal edges is typically several seconds.
> Most one-shots I've found assume a trigger pulse much shorter than the
> one-shot itself and I need the reverse. An input that initiates an
> identical pulse at either edge would be ideal.
> Price is a consideration - a cheap timer and few external components is a plus.
> I want to implement a sleep mode whose quiescent current only powers the touch sensor (at ~ 5nA) to maximize battery life with all else being off.
--
This email has not been checked by half-arsed antivirus software
Martin Brown
Jan 12, 2018, 3:28:44 AM1/12/18
to
On 11/01/2018 20:57, ted...@gmail.com wrote:
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
> want my uC to do a service operation at each edge of that (possibly
> long) 'pulse'. My uC needs about a second or so from power up to the
> beginning of program start. The uC is energized by that sensor
> signal being ON. At program start it immediately asserts another bit
> that controls whether to continue power to itself and other circuits.
> So the one-shot duration is just long enough to wake up the uC, which
> then services the event and then goes back to sleep.
Doesn't the CPU support a hibernate mode with wake on change for certain
> Hi and thanks for responding.
>
> I have a touch sensor. Goes on when touched and off when not. I
> want my uC to do a service operation at each edge of that (possibly
> long) 'pulse'. My uC needs about a second or so from power up to the
> beginning of program start. The uC is energized by that sensor
> signal being ON. At program start it immediately asserts another bit
> that controls whether to continue power to itself and other circuits.
> So the one-shot duration is just long enough to wake up the uC, which
> then services the event and then goes back to sleep.
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.
The sleep and hibernate modes are worth studying (as is figuring out the
minimum clock rate you can operate at and still be just fast enough).
32kHz watch crystals are cheap and plenty fast enough for a user
interface or slowish mechanical event timing. Rough and ready RC clock
timing is even cheaper and you can have a turbo mode if you need one by
having the CPU alter the resistor if it needs a burst of speed.
It seems a bit brute force and crude to start up from cold every time.
> I plan to use a four cell (or possibly six) penlight pack for power.
> I'm hoping to tolerate battery decay to just above 3.3 volts from a
> max of about 6 or 9.
push them that far. Duracells these days seem particularly prone to
leaking if used in low voltage tolerant low current drain LCD devices.
I notice in passing that Everyready are advertising their latest
alkaline offering as "leak free" - that *is* a brave claim.
>
> So the one-shots are about a second or so in duration and the spacing
> between the sensor signal edges is typically several seconds. Most
> one-shots I've found assume a trigger pulse much shorter than the
> one-shot itself and I need the reverse. An input that initiates an
> identical pulse at either edge would be ideal.
>
> Price is a consideration - a cheap timer and few external components
> is a plus.
>
> I want to implement a sleep mode whose quiescent current only powers
> the touch sensor (at ~ 5nA) to maximize battery life with all else
> being off.
It probably isn't worth getting average quiescent current much below the
> So the one-shots are about a second or so in duration and the spacing
> between the sensor signal edges is typically several seconds. Most
> one-shots I've found assume a trigger pulse much shorter than the
> one-shot itself and I need the reverse. An input that initiates an
> identical pulse at either edge would be ideal.
>
> Price is a consideration - a cheap timer and few external components
> is a plus.
>
> I want to implement a sleep mode whose quiescent current only powers
> the touch sensor (at ~ 5nA) to maximize battery life with all else
> being off.
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 find on very low current draw devices <10uA the battery life is more
dependent on the ambient temperature than the load.
--
Regards,
Martin Brown
Phil Hobbs
Jan 12, 2018, 12:33:55 PM1/12/18
to
Jim Thompson
Jan 12, 2018, 1:48:32 PM1/12/18
to
On Thu, 11 Jan 2018 10:23:09 -0800 (PST), ted...@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
The "standard" approach...
>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
<http://www.analog-innovations.com/SED/PulseOnBothEdges.png>
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
Jasen Betts
Jan 12, 2018, 3:31:22 PM1/12/18
to
On 2018-01-12, Jim Thompson <To-Email-Use-Th...@On-My-Web-Site.com> wrote:
> On Thu, 11 Jan 2018 10:23:09 -0800 (PST), ted...@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
>
> The "standard" approach...
>
><http://www.analog-innovations.com/SED/PulseOnBothEdges.png>
>
> ...Jim Thompson
I guess that's always good for a pulse wide enough to clock a
> On Thu, 11 Jan 2018 10:23:09 -0800 (PST), ted...@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
>
> The "standard" approach...
>
><http://www.analog-innovations.com/SED/PulseOnBothEdges.png>
>
> ...Jim Thompson
flip-flop.
Jasen Betts
Jan 12, 2018, 3:31:22 PM1/12/18
to
unpopular part, but TI is still making them.
Jim Thompson
Jan 12, 2018, 3:43:25 PM1/12/18
to
the 'HC74 and pin-2 of the'HC86.
ted...@gmail.com
Jan 13, 2018, 11:47:15 AM1/13/18
to
Hi, thanks for the responses. Give me a moment to study them and I'll respond to every post. In the meantime, if you know of any good repositories for spice .SUBCKTs or .MODELs or Eagle files or LTCSpice schematics, please point me to em. thx Ted
ted...@gmail.com
Jan 13, 2018, 12:07:12 PM1/13/18
to
> interrupt on pin change?
Currently, that would require my Bluetooth Bee Standalone v1 (the uC) to remain energized to catch the interrupt, but it's for development. The final choice of uC is still up in the air, I know some uCs have a low power standby wake on interrupt mode, and I'm open to suggestions like Phil's and yours to make that power savings an intrinsic part of the design if possible.
Thanks,
Ted
Currently, that would require my Bluetooth Bee Standalone v1 (the uC) to remain energized to catch the interrupt, but it's for development. The final choice of uC is still up in the air, I know some uCs have a low power standby wake on interrupt mode, and I'm open to suggestions like Phil's and yours to make that power savings an intrinsic part of the design if possible.
Thanks,
Ted
ted...@gmail.com
Jan 13, 2018, 4:17:31 PM1/13/18
to
I've simulated in LTSpice an RC (1Meg,0.5u) input to XOR approach that is simple, cheap, detects both edges, and produces the needed 'one-shot' width to wake up the uC. Just an RC into the XOR. Unless it's flawed. Thanks, Ted
rickman
Jan 13, 2018, 4:46:50 PM1/13/18
to
ted...@gmail.com wrote on 1/13/2018 4:17 PM:
> I've simulated in LTSpice an RC (1Meg,0.5u) input to XOR approach that is simple, cheap, detects both edges, and produces the needed 'one-shot' width to wake up the uC. Just an RC into the XOR. Unless it's flawed. Thanks, Ted
Simulations are rarely real world realistic. So you need to know where the
> I've simulated in LTSpice an RC (1Meg,0.5u) input to XOR approach that is simple, cheap, detects both edges, and produces the needed 'one-shot' width to wake up the uC. Just an RC into the XOR. Unless it's flawed. Thanks, Ted
bodies are buried. In this circuit it will be the noise sensitivity.
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. Picking a FF that is easy to manipulate is
where the bodies are buried on this approach. You can use a $0.25 part and
a pair of pins on the CPU or a bit more complex one wire part (I think a
dollar?) and a single pin on the MCU. Can the MCU remember the present
state of the FF? If not the $0.25 part will need an input pin to read the
value or maybe a resistor to allow the FF to drive the data signal when the
MCU output is tristate. The one wire solution still only uses one wire.
Multisecond analog delays are asking for trouble in a digital design.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
Jasen Betts
Jan 14, 2018, 4:01:18 AM1/14/18
to
addition to the flip-flop, that seems pretty solid.
ted...@gmail.com
Jan 15, 2018, 4:15:54 PM1/15/18
to
ted...@gmail.com
Jan 15, 2018, 5:36:48 PM1/15/18
to
> why do you need the one-shot when the sensor turns on?
A power enable to the uC long enough for the uC to wake up and get ready for it's little digital day and control continued power to itself. The sensor indicates a change in condition that must be serviced.
> so, how does ths work when the sensor turns off again - what powers the one-shot?
ted...@gmail.com
Jan 15, 2018, 6:12:18 PM1/15/18
to
> 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.
>
> 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.
> 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.
ted...@gmail.com
Jan 15, 2018, 6:33:18 PM1/15/18
to
Thanks for that. Looks good for high speed circuits. I may not need any memory function and the sensor out directly to an RC (low pass filter) to a Schmidt comparator may fit the bill by supplying both the edge detection function and the one-shot function in a remarkably simple circuit (a resistor, a capacitor and an XOR), whether or not noise becomes an issue as Rick suggests. Ted
ted...@gmail.com
Jan 15, 2018, 6:39:44 PM1/15/18
to
> microfarads,megaohms and a CD4070BE will achieve that, seems an
> unpopular part, but TI is still making them.
I think that's the simplest approach. I think the R and the C can be tweaked if necessary and still get the same time constant. Ted
> unpopular part, but TI is still making them.
ted...@gmail.com
Jan 15, 2018, 6:44:10 PM1/15/18
to
> If you're squeamish add an even number of inverters between pin-5 of
> the 'HC74 and pin-2 of the'HC86.
Ugh. I'd rather use up the unneeded three extra XOR gates in a (never seems to be smaller than 14 pins) XOR chip. Are there no 8pin XOR chips anymore? Or even 6pin? Ted
> the 'HC74 and pin-2 of the'HC86.
Lasse Langwadt Christensen
Jan 15, 2018, 6:49:58 PM1/15/18
to
ted...@gmail.com
Jan 15, 2018, 7:01:21 PM1/15/18
to
> 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
> 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.
Joerg
Jan 15, 2018, 7:05:13 PM1/15/18
to
On 2018-01-11 10:23, ted...@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
> 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
>
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/
ted...@gmail.com
Jan 15, 2018, 7:22:28 PM1/15/18
to
> 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'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
Lasse Langwadt Christensen
Jan 15, 2018, 7:39:20 PM1/15/18
to
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
> > 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
the board and trying to hold in parts before soldering, just align part and
tack one pin and solder
k...@notreal.com
Jan 15, 2018, 7:51:52 PM1/15/18
to
On Mon, 15 Jan 2018 16:22:19 -0800 (PST), ted...@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
>> 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
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.
Mike Perkins
Jan 15, 2018, 8:05:55 PM1/15/18
to
like connectors. Otherwise I entirely agree.
--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk
k...@notreal.com
Jan 15, 2018, 9:01:55 PM1/15/18
to
On Tue, 16 Jan 2018 01:05:51 +0000, Mike Perkins <sp...@spam.com>
wrote:
Oh, certainly. PTH capacitors may have lower ESL and ESR, as well. We
often use PTH capacitors, inductors, and of course, connectors.
wrote:
often use PTH capacitors, inductors, and of course, connectors.
rickman
Jan 16, 2018, 1:03:00 AM1/16/18
to
entirely unlikely) you will need some FF external to the MCU in addition to
the XOR.
Martin Brown
Jan 16, 2018, 3:15:23 AM1/16/18
to
On 15/01/2018 23:12, ted...@gmail.com wrote:
>> 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
>> 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.
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
>> 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).
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
Joerg
Jan 16, 2018, 10:43:39 AM1/16/18
to
On 2018-01-15 22:02, rickman wrote:
> ted...@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.
>
That's what depletion mode FETs and charge pumps are for :-)
> ted...@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.
>
Joerg
Jan 16, 2018, 10:54:13 AM1/16/18
to
On 2018-01-15 16:51, k...@notreal.com wrote:
> On Mon, 15 Jan 2018 16:22:19 -0800 (PST), ted...@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.
> On Mon, 15 Jan 2018 16:22:19 -0800 (PST), ted...@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.
>
Absolutamente. Ted would be missing out on most of the good stuff these
> prototyping. You really should get the proper tools and leave
> thru-hole behind. You're really limiting yourself - thru-hole is
> dead.
>
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.
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