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hitsware2

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Joined: 03/08/2019
Location: United States
Posts: 719

Posted: 12:39am 16 Jul 2020

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I would like to build ( or perhaps simply program )
a matrix oscilloscope .
Something like :

But more like 64 x 128 ( 255 x 255 ? )
Since higher resolution displays have no pin out to rows and columns
What ( I think ) I need is a display + display controller
+ micro ( processor and / or controller ) that will produce a ' pset '
at the conjunction of 2 8-bit values .
NOT storage of the whole screen , but simulation of a CRT ....

I.E.
oscillator driving 8 bit counter on columns and 8 bit flash A to D
on rows .........

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vegipete

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Joined: 29/01/2013
Location: Canada
Posts: 1132

Posted: 05:46pm 16 Jul 2020

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I found good prices for LED modules at this supplier but interfacing to these displays is a little bit involved. A simple arduino can handle smaller modules, more grunt is needed for bigger ones. Because the modules need fast continuous refresh, a Micromite likely can't handle it without internal firmware support. Once the module and controller are figured out, they can be treated like any other display as far as a Micromite is concerned.

Then again, because the modules are shift register driven, it might be possible to do everything with discrete TTL. The tough part is the 'strange' interleaving of the module columns...

Visit Vegipete's *Mite Library for cool programs.

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10310

Posted: 06:22pm 16 Jul 2020

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This any use as a display?

hitsware2

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Posted: 07:17pm 16 Jul 2020

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matherp said This any use as a display?

If it was ....
Could I simulate an analog (crt) with it ?
One pixel on at a time ..
Chosen by by 2 values ..
No storage ..

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matherp
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Joined: 11/12/2012
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Posts: 10310

Posted: 09:41pm 16 Jul 2020

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Quote Could I simulate an analog (crt) with it ?
One pixel on at a time ..
Chosen by by 2 values ..

It just acts as a standard display using all the normal graphics commands so
PIXEL x,y,colour
lights a specific LED

hitsware2

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Location: United States
Posts: 719

Posted: 10:30pm 16 Jul 2020

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> Current refresh rate is 62.5FPS on an MX170 Micromite

How would that effect trying to emulate a CRT ?
Doesn't it imply some kind of storage ?
Or do S.S. displays all demand that ?
( I may be getting beyond my technical capacities :( )

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darthvader
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Joined: 31/01/2020
Location: France
Posts: 87

Posted: 10:53pm 16 Jul 2020

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Algorithm for this will be: for time base of 10mS

Time_Base = 10
Ms_Time = Actual_Time

For X = 0 to MM.Hres
While (Ms_Time + Time_Base ) < Actual_Time : EndWhile

Show LED at X , ADC Value
Ms_Time = Actual_Time
Next X

Loop this function if needed ...

Translate this to MMBasic code

Storage in scope function is useless , what you need is the max performance.
Now if you need storage , you have to record each ADC Values in a defined array that you can show it after the measure.
But from what i read here it's not the case ....

Cheers.

Theory is when we know everything but nothing work ...
Practice is when everything work but no one know why ;)

hitsware2

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Location: United States
Posts: 719

Posted: 12:49am 17 Jul 2020

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What would be the bandwidth of the ADCs on the CMM2 ?

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TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 01:05am 17 Jul 2020

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hitsware2 said What would be the bandwidth of the ADCs on the CMM2 ?

Latest beta has improved things:

Quote Bug fixes from V5.05.03
Set maximum ADC sampling rate to 480KHz on 400MHz processors, 500KHz on 480MHz processors

I have used a sample frequency of 400kHz = 2.5uS sample rate.
Its really good feature is this happens in the background so you can do other things while sampling.

Jim

VK7JH
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hitsware2

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Location: United States
Posts: 719

Posted: 01:36am 17 Jul 2020

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How would that translate to bandwidth ?
Could I put 1 kHz into a pin and get a display
of it onto the VGA out ?
Something like :
do
for x = 0 to 255
pixel x , readadc pin
pause ?
cls
next x
loop
Edited 2020-07-17 11:40 by hitsware2

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