PIC Oscilloscope Clock

For those are not into electronics, you must know that an oscilloscope has basically only one timebase to move the spot horizontally from left to right with the same intensity. The vertical deviation is function to the input voltage. You understand immediately that you can't directly display 7 segment digits, because you can't move the spot from right to left.



By using X/Y mode, where the spot is controlled on two axes by two different voltages, it is possible to draw a picture (as in the examples mentioned above), but a fast digital to analog converter with two channels and at least 8 bits of resolution would be needed.

So we have to deal with a spot that always goes from left to right in the same period of time.
If we want to have a 7segment-like display, we have to draw :

vertical segments : easy to do, just change voltage up and down quickly a few times.
horizontal segments : easy to do, just set a voltage level and keep it as long as you need.

By using 2 PIC outputs and a basic R2R digital to analog converter, we can have up to four different voltage levels : 3 for the vertical segment, and another one where to put the spot when it is not in use to draw a segment.

But the problem is that a 7 segment digit may have up to 3 horizontal lines at a time (like 2, 3, 8, 9..) but we can draw only one during one spot deviation.
So we will have to cheat with retinal persistence and use multiple frames : since we can have only one vertical segment per period, three periods will be needed to draw a full 7 segment digit.

Supposing we want to display 12:34:56 on the screen :

During the first period, we will draw all vertical segments, and horizontal upper segments only :

As a game, I let you try to find out the spot trajectory.
Don't forget the rules :

you can't go backward
you can't clear the spot

But you can move so fast vertically that the eye can't see the spot moving.

The lowest line under the digits is not significant, it his the place where the spot is parked when not used to draw a segment.

Schematic Diagram:






Working Video



for more details see this LINK
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Sat Feb 24 2018, 03:35 AM
Aaquib
I want help for digital ic tester
ExperimenterUK
Tue Feb 20 2018, 04:01 PM
Join up.. and post your problem
Mon Feb 19 2018, 11:17 AM
ashishkumar
i needs help for my project
Mon Feb 19 2018, 11:16 AM
ashishkumar
can i join you guys
ExperimenterUK
Sun Feb 04 2018, 09:38 PM
Hi Dave. Good to see you.
DavesGarage
Tue Jan 09 2018, 07:55 PM
It's been a few years since I poked around here - Hi all...
ExperimenterUK
Mon Jan 08 2018, 07:19 PM
Hi TPS. it's been a while..
۞ TPS ۞
Sun Jan 07 2018, 06:42 PM
hello
Thu Jan 04 2018, 01:50 PM
sayyad affrid
its AT89S52
Thu Jan 04 2018, 01:50 PM
sayyad affrid
sir, i want embedded c code for ultrasonic sensor having buzzer interfaced with AT9S52

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Manojsanghavi Avatar
Posted By Manojsanghavi
Sat Feb 24 2018, 01:03 PM
Dear allCan someone please help me on how to progr...
Ansh12 Avatar
Posted By Ansh12
Fri Feb 23 2018, 07:10 PM
sbit E = P0^7; //E pin for LCD //use port 0sb...
ExperimenterUK Avatar
Posted By ExperimenterUK
Fri Feb 23 2018, 02:43 PM
sbit NOT #definesbit E = P0^7; //E pin for LCD ...
Ansh12 Avatar
Posted By Ansh12
Fri Feb 23 2018, 01:55 PM
change your defines tosbit E = P0^7; //E pi...
ExperimenterUK Avatar
Posted By ExperimenterUK
Fri Feb 23 2018, 01:12 AM
Add pull- ups for EN and RS.change your defines t...
Ansh12 Avatar
Posted By Ansh12
Thu Feb 22 2018, 01:36 AM
Can you post your Proteus files.ExperimenterUKThan...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Feb 21 2018, 09:07 PM
The code you refer to is to drive the circuitshown...
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Posted By ExperimenterUK
Wed Feb 21 2018, 05:41 PM
Can you post your Proteus files.You will need pull...
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Posted By radhikanathani
Wed Feb 21 2018, 02:39 PM
I want to design a system for vehicle tracking and...
Narayani Avatar
Posted By Narayani
Wed Feb 21 2018, 04:17 AM
Hello,Your tutorial really helped me understand st...