I remember years ago seeing a clip that would fit over an IC and show
the logic state of each pin on an LED (or an LED pair). Something like this
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they called?
Do you mean something like this?
https://www.ebay.com/itm/Hewlett-Packard-HP-548A-Logic-Clip/283214879522?epid=1100247702&hash=item41f0ec1b22:g:CuYAAOSw21Rbxt9W:rk:1:pf:0
I think this was only for TTL levels and 5V power.
As noted in my description there, it powers the LEDs from the outputs
of the chip that it's clipped to, which might cause issues in
circuits that can't supply enough extra current.
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour. Is there a better way to monitor digital ICs in-circuit these days?
In sci.electronics.components James Harris <james.harris.1@gmail.com> wrote:
I remember years ago seeing a clip that would fit over an IC and show
the logic state of each pin on an LED (or an LED pair). Something like this >>
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they called?
This is my take on such a device: http://computernerdkev.heliohost.org/logicvis/index.htm
Another DIY design was published in the Aug. 1987 issue of the
Australian version of "Electronics Today International", with the
largely inaccurate name of "In-Circuit Digital IC Tester".
Therefore I made it available on my webpage about DIY IC tester
designs:
http://computernerdkev.heliohost.org/ictesters/index.htm
As noted in my description there, it powers the LEDs from the outputs
of the chip that it's clipped to, which might cause issues in
circuits that can't supply enough extra current.
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I remember years ago seeing a clip that would fit over an IC and show
the logic state of each pin on an LED (or an LED pair). Something like this
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they called?
--
James Harris
On 17/10/2018 23:34, Computer Nerd Kev wrote:
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour. Is there a better way to monitor digital ICs in-circuit these days?
In sci.electronics.components James Harris <james.harris.1@gmail.com> wrote:
On 17/10/2018 23:34, Computer Nerd Kev wrote:
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour. Is there a better way to monitor
digital ICs in-circuit these days?
Of course there are Logic Analysers, but they were around back then
too. These days there are some cheap options for connecting to
a PC though, eg.
http://dangerousprototypes.com/docs/Logic_Pirate
The clip-on indicators were easier to use, but I think the key
limitation is that the only signals that can be reliably
analysed are those slow enough for the eye to observe changing
state. That's why I wanted to build one that allowed various
methods to be used in order to sample and effectively slow
down the display.
I wasn't aware of logic analysers. They sound far better if they have
enough channels. I see many with 8 or 16 channels but a more expensive
Hantek LA5034 which apparently has 34 channels: https://www.circuitspecialists.com/34-ch-usb-logic-analyzer-la-5034.html. Does it look good as a PC-based analyser which could be used in many situations, or would you recommend a different one?
Whether such a piece of kit would be generally useful or not, such an analyser wouldn't help in this specific case as it could not be used to
check the above decoder without also using a test program to cycle
through the inputs. The decoder is not socketed so I guess all I can do
is unsolder the chip and test the 16 permutations of its inputs on a breadboard. If I'm wrong and there is a better approach please say!
On 17/10/2018 23:34, Computer Nerd Kev wrote:
In sci.electronics.components James Harris
<james.harris.1@gmail.com> wrote:
I remember years ago seeing a clip that would fit over an IC and
show the logic state of each pin on an LED (or an LED pair).
Something like this
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they
called?
This is my take on such a device:
http://computernerdkev.heliohost.org/logicvis/index.htm
Another DIY design was published in the Aug. 1987 issue of the
Australian version of "Electronics Today International", with the
largely inaccurate name of "In-Circuit Digital IC Tester".
Therefore I made it available on my webpage about DIY IC tester
designs: http://computernerdkev.heliohost.org/ictesters/index.htm
That brings back memories!
As noted in my description there, it powers the LEDs from the
outputs of the chip that it's clipped to, which might cause issues
in circuits that can't supply enough extra current.
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour.
digital ICs in-circuit these days?
On 10/18/2018 12:39 PM, James Harris wrote:
On 17/10/2018 23:34, Computer Nerd Kev wrote:
In sci.electronics.components James Harris
<james.harris.1@gmail.com> wrote:
I remember years ago seeing a clip that would fit over an IC and
show the logic state of each pin on an LED (or an LED pair).
Something like this
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they
called?
This is my take on such a device:
http://computernerdkev.heliohost.org/logicvis/index.htm
Another DIY design was published in the Aug. 1987 issue of the
Australian version of "Electronics Today International", with the
largely inaccurate name of "In-Circuit Digital IC Tester".
Therefore I made it available on my webpage about DIY IC tester
designs: http://computernerdkev.heliohost.org/ictesters/index.htm
That brings back memories!
As noted in my description there, it powers the LEDs from the
outputs of the chip that it's clipped to, which might cause issues
in circuits that can't supply enough extra current.
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour.
They aren't much use for anything faster than a burglar alarm. Usually
they just told you high, low or 'pulsing'. Nobody builds burglar alarms
out of TTL anymore.
Is there a better way to monitor
digital ICs in-circuit these days?
A logic analyzer. You can get slow USB ones for under $100, and pretty
fast ones for $300.
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
On Tuesday, October 23, 2018 at 12:08:09 PM UTC-4, Phil Hobbs wrote:
On 10/18/2018 12:39 PM, James Harris wrote:
On 17/10/2018 23:34, Computer Nerd Kev wrote:
In sci.electronics.components James Harris
<james.harris.1@gmail.com> wrote:
I remember years ago seeing a clip that would fit over an IC and
show the logic state of each pin on an LED (or an LED pair).
Something like this
https://uk.farnell.com/3m/923690-08/test-clip-dil-8way/dp/178270
Do such clips still exist but with LEDs on top and what are they
called?
This is my take on such a device:
http://computernerdkev.heliohost.org/logicvis/index.htm
Another DIY design was published in the Aug. 1987 issue of the
Australian version of "Electronics Today International", with the
largely inaccurate name of "In-Circuit Digital IC Tester".
Therefore I made it available on my webpage about DIY IC tester
designs: http://computernerdkev.heliohost.org/ictesters/index.htm
That brings back memories!
As noted in my description there, it powers the LEDs from the
outputs of the chip that it's clipped to, which might cause issues
in circuits that can't supply enough extra current.
Similar pre-built devices were sold at the same time, but I don't
know of any still available.
I wonder why they fell out of favour.
They aren't much use for anything faster than a burglar alarm. Usually
they just told you high, low or 'pulsing'. Nobody builds burglar alarms
out of TTL anymore.
Is there a better way to monitor
digital ICs in-circuit these days?
A logic analyzer. You can get slow USB ones for under $100, and pretty
fast ones for $300.
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
Just curious, can you supply a pointer or two to some of the high end analyizers at ~$300-400?
Thanks
J
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