Gabotronics

Specifications

1 Analog Input
Input Impedance: 1M?
Maximum Input Voltage: +/- 25V
(+/- 250V if using a 10:1 probe)
A/D Converter Resolution: 8 bits
Max Sample Rate: 3.2MS/s
Trigger jitter: 312.5nS
3 Digital Inputs: 5V level

K2: Set rotary encoders to control horizontal cursors,

Toggles horizontal cursors on and off.

K3: Set rotary encoders to control vertical cursors,

In normal mode:

Displays the Average (DC) & Peak to Peak voltage (PP) of the waveform

In FFT mode:

Displays the fundamental frequency of the waveform

K6: Digital inputs control, K6 cycles between these modes:

The trigger will occur on the rising edge of the pulse.
Note: K6 only controls the trigger source; enabling the oscilloscope trigger is set with K7 (example: setting the trigger to NORMAL).
The digital inputs are the lines used for the ISP (PB5, PB6, PB7).
When a digital line is "low", the trace will be 2 pixels wide.

K7: Sets the rotary encoders for trigger control

Rotary Encoder 1: Sets the trigger level
Move encoder up for rising edge trigger
Move encoder down for falling edge trigger
The arrow on the left side of the LCD represents the trigger level and edge direction

Rotary Encoder 2: Sets the trigger mode:

• NORMAL mode (trace when trigger occurs)
• FREE (trace continuously)
• Single NORMAL (trace once when trigger occurs)
• Single FREE (trace once)

Once in trigger control, the behavior of K7 also changes:
If in Normal or Free mode, K7 will toggle between RUN and STOP.
If in Single mode, K7 will allow one more trace to be drawn.

NOTE: Keys K1 thru K6 are disabled when the scope is waiting for the trigger (NORMAL modes). If the scope doesn't have a signal that continuously triggers the scope, K1-K6 will not respond. This is a necessary behavior since the trigger is detected by software, keys K1 thru K6 are checked continuously using the AVR's ADC and would add trigger jitter if left enabled. Key K7 and rotary encoders are never disabled.

WORKAROUND to enable K1-K6 at the absence of a trigger:

1. Use K7 to STOP the scope.
2. Adjust the trigger level to find the signal
3. Set the FREE trigger mode

• Normal display
• Persistent display (traces will not be erased)

TIP: The persistent display is useful as a data logger or to catch glitches in the waveform

• Line display (default mode, a line is drawn from sample to sample)
  Dot display (each sample is displayed as a single pixel)

TIP: The dot display is useful at slow sampling rates or when used in combination with the persistent mode.

• Hamming window for FFT (default)
• No Hamming window for FFT

The Hamming window is useful when the number of cycles of the waveform is not an integer. Example:

Approx. 4.5 cycles	No Window	Hamming window

• Don't apply a log to the FFT (default)
• Apply log to the FFT

The log is useful when analyzing low level components on the signal. When analyzing audio, it is also very useful as it maps more directly to how humans perceive sound. Example:

Triangle wave	No logarithm	Using logarithm

AC/DC/GND Jumper: Selects the different input coupling options:

DC Coupled	Ground	AC Coupled