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MarcDraco
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2020-09-11 4:22 pm  

https://wemakethings.net/2012/10/04/catnip/

Seems an old post, but based on the reference images they supplied the ADC performance is greatly improved over the utterly dire ones I've experienced on the Arduino.

I don't know if anyone suggested this yet Bill, but my lorks, the ADCs on these fellas are noisy for sensitive measurements (as I learned when I got a cheap digital scope from China recently). This thing is so bad it's almost unusable and it's entirely down to ADC noise!


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DroneBot Workshop
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2020-09-11 4:45 pm  

So is it the LPC1343 you are interested in, or an improved ADC?  Because the spec sheet for the LPC1343 shows that it also has a 10-bit ADC, the same resolution as the Arduino, although it probably is faster as its clock speed is a lot higher.  Otherwise, I'm puzzled as to what improvement you'd see here, unless it has a lower noise floor?

The ESP-32 has a 12-bit ADC and is faster than both chips.

Perhaps I'm missing the point here, so please feel free to enlighten me!

😎

Bill

 

 

"Never trust a computer you can’t throw out a window." — Steve Wozniak


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MarcDraco
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2020-09-24 12:28 am  

I don't think it's noise floor, reading the AVR spec sheets they seem to suggest that to get the best ADC readings you need to shutdown the processor (essentially) so that, what I assume is digital noise, doesn't bleed on to the traces.

You can see it even on the product pictures on these ultra-cheap scopes.

I guess for $15-20 or so you can't expect much!

Also: sorry for late reply, I didn't get a notification and I've been busy watching your tutorials and making my first "major" Arduino project for Instructibles.

 

This post was modified 2 months ago by MarcDraco

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MarcDraco
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2020-09-27 3:34 am  

Found it at last @dronebot-workshop

It's in the data sheet/ Sorry this is a bit wonky. I'm almost asleep!

ADC Noise Reduction Mode
When the SM2..0 bits are written to 001, the SLEEP instruction makes the MCU enter ADC noise reduction mode, stopping the CPU but allowing the ADC, the external interrupts, the 2-wire serial interface address watch, Timer/Counter2(1), and the
watchdog to continue operating (if enabled). This sleep mode basically halts clkI/O, clkCPU, and clkFLASH, while allowing the other clocks to run.

This improves the noise environment for the ADC, enabling higher resolution measurements. If the ADC is enabled, a conversion starts automatically when this mode is entered. Apart from the ADC conversion complete interrupt, only an
external reset, a watchdog system reset, a watchdog interrupt, a brown-out reset, a 2-wire serial interface address match, a Timer/Counter2 interrupt, an SPM/EEPROM ready interrupt, an external level interrupt on INT0 or INT1 or a pin change
interrupt can wake up the MCU from ADC noise reduction mode.


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