GBS Elektronik MCA-527 Oscilloscope Mode - Manual (Page 5)

Description of the MCA527 Oscilloscope Mode
2.2 Settings
The oscilloscope mode is entered with the firmware command CMD_SET_GENERAL_MODE. Set the
general mode to GMODE_OSCILLOSCOPE = 2.
The fundamental parameters for the oscilloscope mode are trigger source, threshold, resolution and
position. They can be set with the firmware command CMD_SET_OSCI_TRIGGER.
The trigger source can be set to: 0 untriggered
1 triggered at rising edge
2 triggered at falling edge
3 triggered at both edges
4 triggered by the selected trigger filter 2
The threshold can be from 0 to 16383. It refers to ADC digits and is meaningful if the trigger source is set to
rising, falling or both edges. It is possible to convert the ADC digits into voltage values. This conversion is
described in chapter 2.5.
The resolution specifies the time interval between two data points. The values -5 … 0 result in the same
time interval but with the assistance of this values, the application can scale the time axis of the oscilloscope
screen. (The right column shows the resulting interval per division for an oscilloscope screen with 500 pixel
width and 10 divisions.)
The resolution can be set to: -5 100ns (100ns/DIV)
-4 100ns (200ns/DIV)
-3 100ns (500ns/DIV)
-2 100ns (1µs/DIV)
-1 100ns (2µs/DIV)
0 100ns (5µs/DIV)
1 200ns (10µs/DIV)
2 400ns (20µs/DIV)
3 1µs (50µs/DIV)
4 2µs (100µs/DIV)
5 4µs (200µs/DIV)
6 10µs (500µs/DIV)
7 20µs (1ms/DIV)
8 40µs (2ms/DIV)
9 100µs (5ms/DIV)
10 200µs (10ms/DIV)
11 400µs (20ms/DIV)
12 1ms (50ms/DIV)
13 2ms (100ms/DIV)
The position can be from 0 to 499. It defines the data point that marks the trigger point and is meaningful if
the trigger source is set to “triggered”.
2.3 Starting and Stopping the Oscilloscope Measurement
The oscilloscope measurement is started with the firmware command CMD_START. All parameters of this
command are ignored in oscilloscope mode. The oscilloscope measurement is stopped again with the
firmware command CMD_STOP. Each time before the application calls a setting firmware command, it has
to stop the oscilloscope measurement and restart it again.
2 see CMD_SET_TRIGGER_FILTER
5