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NPHighview

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Joined: 02/09/2020
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Posted: 09:40pm 18 Aug 2023

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Thank you!

I've ordered some panel mount switches (for these three functions, and also to switch between DC-coupled and AC-coupled), the connector and lithium battery for this board, and am going to try to design and build an enclosure. With battery operation, I won't be concerned about messing up ground.

Live in the Future. It's Just Starting Now!

stanleyella

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Joined: 25/06/2022
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Posted: 10:01pm 18 Aug 2023

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NPHighview said Hi - I've got three momentary-contact, pushbutton switches, one to cycle through time / ADC frequency, the next to select triggering, the the last to cycle through voltage ranges. See my Handle_Pushbuttons subroutine.

Tidy. on a touch ili maybe or even a 5 button pad with a-d output on 1 a-d pin.
very nice work you guys doing. interesting the things in mmbasic if one delves deeper

stanleyella

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Posted: 10:25pm 18 Aug 2023

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I got a few of these not working anymore cos I reflashed the firmware unsuccessfully but as new are better than a picoscope... that's not the point though, you don't learn anything except don't believe the bandwidth
https://www.ebay.co.uk/itm/404355142567?
oops they were £12 when I got mine
Edited 2023-08-19 08:30 by stanleyella

Mixtel90

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Posted: 06:32am 19 Aug 2023

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Those aren't as horrible as they look and are quite usable for some jobs. My brother used one as his only scope for a while (just for fault finding on audio stuff). I have it now but it's at the bottom of a box of other stuff.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

stanleyella

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Posted: 01:23pm 19 Aug 2023

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Mick, the SETPIN pin, cfg [, option] seems to measure frequency FIN Frequency input.
Could this be useful to set display or sampling rate? just a thought.
I'll dig out the duff scopes and try reflashing. When £12 the firmware was iffy.

Mixtel90

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Posted: 01:54pm 19 Aug 2023

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It will measure frequency providing that the input signal is a sensible waveform that is either a square wave or one that the schmitt trigger input will convert into one. It may not work with, say, a narrow pulse waveform or a sawtooth waveform for example. I don't know, I haven't tried it.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

stanleyella

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Posted: 02:56pm 19 Aug 2023

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NPH, Hi! I tried your scope v1 and v2 in page 4 in this thread and it's very nice.
removed the random pwm mark space. Looks nice display. How come I never got that using pixels??
10000Hz sine with dc offset
The cursor is not mid screen??

Edited 2023-08-20 00:59 by stanleyella

NPHighview

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Posted: 03:47pm 19 Aug 2023

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Ooh - that looks good! I don't have a signal generator, and could only use the PWM test signal.

I set the cursor at 3/4 the way to the bottom to show DC signals (the cursor is at 0VDC). I have a 3PDT switch on the way; I will use two poles to switch the R/C network in and out to center the signal, and the 3rd pole to indicate to the program whether this is an AC or a DC signal, and move the cursor appropriately.

I see the resistor in your photo - is that to do current limiting between the test signal output on pin 24 and the signal input on 31?

You're also using an older version of my code - I don't see the Trigger symbol ("/", "\", "-") in the middle. My newest version is on my GitHub page, linked here.

Please - if I've used your ideas, but haven't credited you in the comments, please let me know and I'll fix it. I'm in early discussions to write a magazine article about MMBasic, PicoMite firmware, the Back Shed Forum, in the context of this project.

Live in the Future. It's Just Starting Now!

stanleyella

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Posted: 05:29pm 19 Aug 2023

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Hi NPH. resistor is pwm test. dunno..supposed to.
you and phil99 and matherp got a result.
You did publish a keyboard version and I got a vga kb but thought tiny board - big kb no.
ili touch is the way but I had probs with layer mem.
The original post by Bleep has changed a bit.
For me it's not the final code??? but the journey to it. I'm learning new stuff all the time.
Did you see my question about freq in? a pin connected to a-d in and measure freq then set suitable time base for display.
cheers stan
ps triangles

Edited 2023-08-20 04:50 by stanleyella

phil99

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Posted: 10:45pm 19 Aug 2023

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@carlschneider - Continuing your ADC query on the PicoMite Beta thread.

Do you need a separate AIN reading? The value you want will be in the array.

SetPin GP26, AIN 'single ADC channel
SetPin GP27, DIN 'used for PULSIN
DIM ADCOutput!(10) ' take 10 samples
ADC OPEN 250000,1,ADCComplete 'eventually 2 ADC so total still 500kHz

ADCOutput!(10) = -1
ADC START ADCOutput!() ' called from inside a 10s Tick subroutine

Do While ADCOutput!(10) < 0 : Loop ' Wait until the array is full
ADCComplete

SUB ADCComplete
ADCVoltage = ADCOutput!(10)
PRINT ADCVoltage;" Volts"
END SUB

or, for the mean

SUB ADCComplete
For n = 0 to 10
ADCVoltage = ADCOutput!(n) + ADCVoltage
Next
ADCVoltage = ADCOutput!(n) / 11
PRINT ADCVoltage;" Volts"
END SUB

Edited 2023-08-20 08:55 by phil99

stanleyella

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Posted: 10:47pm 19 Aug 2023

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my Pic based sig gen and a sig gen chip spoiled by being cheap.. but cheap and works.

stanleyella

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Posted: 12:27am 20 Aug 2023

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these are a common chip but done cheap but work as a sig gen

phil99

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Posted: 12:30am 20 Aug 2023

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@CarlSchneider - Some careless copy-and-paste in my last post above Stan's. Amended code.

DIM ADCOutput!(10) ' take 10 samples
ADC OPEN 250000,1,ADCComplete 'eventually 2 ADC so total still 500kHz

ADC START ADCOutput!() ' called from inside a 10s Tick subroutine
Pause 1 ' Wait for ADC to fill array

SUB ADCComplete
ADCVoltage = ADCOutput!(10)
PRINT ADCVoltage;" Volts"
END SUB

or, for the mean

Dim ADCOutput!(10) ' take 10 samples
ADC OPEN 250000,1,ADCComplete 'eventually 2 ADC so total still 500kHz

ADC START ADCOutput!() ' called from inside a 10s Tick subroutine
Pause 1 ' Wait for ADC to fill array

Sub ADCComplete
ADCVoltage = ADCOutput!(10)
Print ADCVoltage;" Volts"
ADCVoltage = 0
For n = 0 To 9
ADCVoltage = ADCOutput!(n)*0.1 + ADCVoltage
Next
Print ADCVoltage;" Volts"
End Sub

Edited 2023-08-20 12:00 by phil99

NPHighview

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Joined: 02/09/2020
Location: United States
Posts: 200

Posted: 03:12am 20 Aug 2023

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Stan - Good idea re: measuring the frequency & auto-ranging as appropriate. I'll give it a try. I like auto-ranges that turn out to be multiples of 2, 5, or 10, and once had a routine that would take a number and return the most sensible range. I'll have to dig that back up.

But first, the switches arrived today (as did a LiPo battery, but not the correct connector). A neighbor has a business with an X-Carve and a laser cutter, so I'm going to do an initial design and prototype for a case and hand it over to him to refine and finish. I figure aircraft plywood (3mm or 6mm) should make a great enclosure, with some smoke-colored plexiglas (perspex?) for a spacer. Now that I have the battery, I should be able to figure out the layout without much problem.
- Steve

Live in the Future. It's Just Starting Now!

carlschneider
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Joined: 04/08/2023
Location: South Africa
Posts: 158

Posted: 04:28am 20 Aug 2023

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Thanks phil99

Coming from the ESP32, last played with about 2 years ago, I made some erroneous assumptions. I was expecting to find the math manipulated measured voltage in the pin register and thus the pin read failing. If one sets the pin to AIN and reads the pin I wonder what one is reading?

I now realize it can operate as a one-shot or free running depending on the usage of ADC OPEN, START and CLOSE.

I have now configured it as free running (ADC OPEN, START) and when ADCOutput!() is full it calls the ADCComplete subroutine where I MATH MEAN ADCOutput!() to get the voltage measured.

In the 10s Tick subroutine I ADC START each new conversion.

Thanks for your input.

Cheers Carl
Retirement is tough on Hobbies without a day job

phil99

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Posted: 07:27am 20 Aug 2023

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Quote If one sets the pin to AIN and reads the pin I wonder what one is reading?

AIN accesses the A-D hardware separately from the ADC function.
In the firmware AIN reads the pin several times (10 I think), lowest and highest values are discarded and the remainder averaged.
For spot values all that is needed is:

Setpin GPx AIN
.
.
.
Print Pin(GPx)

The effective resolution is 8 or 9 bits due to a fault in the A-D hardware.

carlschneider
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Joined: 04/08/2023
Location: South Africa
Posts: 158

Posted: 01:10pm 20 Aug 2023

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phil99 said AIN accesses the A-D hardware separately from the ADC function.
In the firmware AIN reads the pin several times (10 I think), lowest and highest values are discarded and the remainder averaged.
For spot values all that is needed is:

Setpin GPx AIN
.
.
.
Print Pin(GPx)

The effective resolution is 8 or 9 bits due to a fault in the A-D hardware.

Thanks for the insights, much appreciated.

Cheers Carl
Retirement is tough on Hobbies without a day job

stanleyella

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Posted: 01:45pm 20 Aug 2023

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When I first tried a-d I used test pin a-d but was advised to use the a-d to array.
is it ok to join a pin for a-d to another pin set for sample to array?

phil99

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Posted: 10:16pm 20 Aug 2023

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If you mean connecting an AIN pin to an ADC pin then yes, they are high impedance so don't affect each other.
Results for a 10k pot between 3.3V and Gnd. with wiper to GP26 and GP27.

> Dim Adc(9) : setpin gp27, ain : ADC OPEN 25000,1
> ADC START Adc() : for n=0 to 8 : ? Adc(n), pin(gp27) : next
1.004102564 1.003968254
1.004102564 1.003968254
1.005714286 1.004371184
1.004102564 1.004505495
1.003296703 1.004371184
1.004908425 1.004774115
1.003296703 1.004639805
1.004102564 1.004639805
1.003296703 1.005177045
>

Edited 2023-08-21 11:52 by phil99

stanleyella

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Joined: 25/06/2022
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Posted: 04:05pm 21 Aug 2023

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I had a try at auto range but probs before I start.
the idea was use the freq% to change the sample rate but I'm thick

SetPin GP18,pwm1A 'this optional test signal comment out
PWM 1,10000,30 'square wave ,this optional test signal comment out
dim c%,x%,samples!(360),freq%
SETPIN GP7, FIN
freq%=pin(GP7)' freq of input
print freq%

SETPIN GP26, AIn
adc open freq%,1 '500000,1 'samples per second

RUN
0
[12] ADC open freq%,1 '500000,1 'samples per second
Error : Invalid frequency
edit it must be not measuring freq
Edited 2023-08-22 03:06 by stanleyella

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