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Topic: Toy oscilloscope - 200 ksamp/sec on Arduino Uno/ATmega328P (Read 1 time) previous topic - next topic


Not all finished, but sample rate seems real.
ADC Clock frequency are set to 4 MHz (this is 4x of max allowed value).


What performance can you get at that speed?  I presume the input must be very
low impedance to charge the S/H cap at that rate.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


It is seems that amplifier with 1k output impedance are sufficient.

First channel (green) connected to pwm pin 11 via resistor, second channel (yellow) - to pwm pin 3 directly.
PWM frequency - 3906 Hz. ADC speed - 2x100 ksamp/sec.




Now this amplifier used (R1 = 2.7 .. 110k, Q2 - BC547B), but op amp with rail-to-rail output may be better:


Trying to compile the last version inoscope-00.02.00 I got some errors with IDE 1.6.12

inoscope:225: error: 'setupTimer1' was not declared in this scope
inoscope:278: error: 'setDelay' was not declared in this scope
inoscope:331: error: 'setLevel' was not declared in this scope
inoscope:377: error: 'setStartCond' was not declared in this scope
inoscope:423: error: 'setInverted' was not declared in this scope

but these functions ARE declared in sketch. It seems that the error raise because these functions are called before declaration.

So I rearranged code and now it compiles and tested. IT works.
I have also noticed that COM port number is hardcoded in java sources so I had to change it.


Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0


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