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PicoScope 6000 Series Programmer's Guide 7

3.3

Voltage ranges

You can set a device input channel to any voltage range from ±50 mV to ±20 V with

the ps6000SetChannel function. Each sample is scaled to 16 bits so that the values

returned to your application are as follows:

Constant

Voltage

Value returned

decimal

hex

PS6000_MIN_VALUE

minimum

-32 512

8100

zero

0000

PS6000_MAX_VALUE

maximum

32 512

7F00

3.4

Triggering

PicoScope 6000 Series oscilloscopes can either start collecting data immediately, or be

programmed to wait for a trigger event to occur. In both cases you need to use the

PicoScope 6000 trigger functions ps6000SetTriggerChannelConditions,

ps6000SetTriggerChannelDirections and

ps6000SetTriggerChannelProperties. A trigger event can occur when one of the

signal or trigger input channels crosses a threshold voltage on either a rising or a

falling edge.

3.5

Sampling modes

PicoScope 6000 Series oscilloscopes can run in various sampling modes.

Block mode. In this mode, the scope stores data in internal RAM and then

transfers it to the PC. When the data has been collected it is possible to examine

the data, with an optional downsampling factor. The data is lost when a new run is

started in the same segment, the settings are changed, or the scope is powered

down.

ETS mode. In this mode, it is possible to increase the effective sampling rate of

the scope when capturing repetitive signals. It is a modified form of block mode.

Rapid block mode. This is a variant of block mode that allows you to capture

more than one waveform at a time with a minimum of delay between captures. You

can use downsampling in this mode if you wish.

Streaming mode. In this mode, data is passed directly to the PC without being

stored in the scope's internal RAM. This enables long periods of slow data collection

for chart recorder and data-logging applications. Streaming mode also provides fast

streaming at up to 13.33 MS/s (75 ns per sample) with USB 2.0 or 156 MS/s with

USB 3.0. Downsampling and triggering are supported in this mode.

In all sampling modes, the driver returns data asynchronously using a callback. This is

a call to one of the functions in your own application. When you request data from the

scope, you pass to the driver a pointer to your callback function. When the driver has

written the data to your buffer, it makes a callback (calls your function) to signal that

the data is ready. The callback function then signals to the application that the data is

available.

Because the callback is called asynchronously from the rest of your application, in a

separate thread, you must ensure that it does not corrupt any global variables while it

runs.

In block mode, you can also poll the driver instead of using a callback.