GBDSO 
Digital Sampling Oscilloscope 

10/2000  This project will appear in the October and November 2000 issues of the Elektor Electronics magazine.  You can find details on how to obtain the parts or pre made units in the magazine or on their web site.  Please to not email me about buying or making the units, thank you.
 

Key Features:

The GameBoy digital sampling oscilloscope 'GBDSO' converts a GBpocket or GBcolour into a multipurpose test instrument which should prove invaluable to the hobby designer. Design of GBDSO posed many contrasting requirements: high speed, low power, low cost, small size and versatility.  In order to simplify the hardware as much as possible real time software is used to perform the majority of control functions e.g.: triggering and variable rate sampling. Once captured the sampled data is displayed using a standard oscilloscope 10 by 8 screen format that is designed to maximise screen use.  A simple four position menuing system (one for each key) in combination with the joypad provides easy setting of the standard scope functions.

A number of advanced options are also possible for the more experienced user, these include FFT analysis, XY mode, averaging and reference storage.  A serial data link allows the displayed screen or trace data values to be transferred to a PC computer via the computers printer port, the PC software is MS Windows 95/98 compatible.







The oscilloscope has two input channels CHA/B, with independent software controlled variable gain amplifiers.  The inputs have a 1M( input impedance so they can be connected directly to 1:1 or 10:1 scope probes or to an audio jack lead. The amplifiers can be AC or DC coupled by means of a switch.  The variable gain amplifiers give an input sensitivity of 50mV to 10V per division with 10:1 probes and an input bandwidth of DC to 100KHz (1V/DIV).
 

The displayed trace has two modes of operation, for low frequencies (100S-100mS/DIV) a chart recorder style of display is produced with the trace scrolling across from the right hand side. For high frequencies (50mS-5uS/DIV) an entire screen of data is captured before it is displayed (standard mode).  The number of samples captured per scan may be set to either 240 or 600 points per channel allowing the visible screen window to be moved relative to the initial trigger.  Sampling of the two input channels occurs  simultaneously accept for the 10,5uS/DIV ranges when the channels are sampled on alternate traces relative to the trigger (alternate mode).  CHA may also be saved as an on screen reference thus allowing a total of three traces to be displayed at once.

Some more screen shots

If you would like to try out a demonstration rom image then try this:-
 
 

Demo Rom image "now available"





The file is a standard ROM image and should run with most GameBoy emulators eg: GB97 see my Gameboy page for more info.
Although I do not seek to profit from this project (considering the year spent on it), under an agreement with the magazine I am not allowed to supply ROM's or any other materials relating to this project.  So if you would like to build a unit for yourself then check out the magazine.
 
I have updated the GBDSO grab utility to run under Windows XP if you install the supplied driver. Please follow the instructions in the readme.txt for details.

"PLEASE DO NOT CONTACT ME
I WILL NOT RESPOND TO ANY QUESTIONS"

Try the Elektor Electronics magazine
 
 


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