WaveForms™ provides an interface that allows users to interact with Digilent Analog Design hardware, such as the Analog Discovery™ and Electronics Explorer™. While the WaveForms application offers a refined graphical interface, the WaveForms SDK provides access to a public application programming interface (API) that gives users the ability to create custom PC applications. This WaveForms SDK manual describes the main components and architecture of the WaveForms system and details each function contained in the WaveForms API. The SDK package also offers examples demonstrating how to identify, connect to, and control analog hardware devices.

The WaveForms system is comprised of multiple components. The most visible component is the WaveForms Application; a suite of graphical instrument panels that give full access to the analog and digital instruments in the connected hardware. The WaveForms application uses the WaveForms Runtime to control all signal generation and acquisition. The WaveForms Runtime is comprised of the DWF Dynamic Library and several configuration files. This library is located in:

• Windows in System Directory: C: \Windows\System32\dwf.dll
• Linux: /usr/lib/libdwf.so.x.x.x

The static library is located on Windows in the install path:

• Windows 32bit: C:\Program Files\Digilent\WaveFormsSDK\lib\x86
• Windows 64bit: C:\Program Files (x86)\Digilent\WaveFormsSDK\lib\x64

The C header file is located in:

• Windows: C:\Program Files\Digilent\WaveFormsSDK\inc
• Windows 64bit: C:\Program Files (x86)\Digilent\WaveFormsSDK\inc
• Linux: /usr/local/include/digilent/waveforms

Working code examples are provided with the SDK to demonstrate basic use of each API function set. You can find samples in the installation directory, which are located here:

• Windows 32bit: C:\Program Files\Digilent\WaveFormsSDK\samples
• Windows 64bit: C:\Program Files (x86)\Digilent\WaveFormsSDK\samples
• Linux: /usr/local/share/digilent/waveforms/samples

The DWF Library uses the Adept Runtime, which provides basic communication with the targeted hardware instruments (i.e. Analog Discovery and Electronics Explorer). Although the Adept Runtime is an integral part of the WaveForms System, knowledge of its structure is not required to write custom applications.

The requirements for Linux version are the libusb-1.0-0, Digilent Adept Runtime, and the included FTDI drivers:

$ sudo apt-get install linusb-1.0-0 digilent.adept.runtime_#/ftdi.drivers_# $ sudo bash install.sh digilent.adept.runtime_# $ sudo bash install.sh

Everything needed to write custom applications is included in the WaveForms SDK, which provides the header/library files and documentation to access the API for the DWF Library. A custom application must properly link to these files to make the appropriate API function calls. Every function in the WaveForms public API is declared in the dwf.h header file.

Basic usage of the WaveForms API can be broken down into the following steps:

1. Call enumeration functions to discover connected hardware devices.
2. Call FDwfDeviceOpen function to establish a connection to specific hardware device.
3. Call function to enable instrument within hardware device.
4. Call functions to configure instrument and acquire/generate signals.
5. Call function to disable instrument.
6. Call FDwfDeviceClose function to disconnect from device.

There are nine main groups of API functions, each named with different prefixes:

Each instrument is directly controlled using three types of functions in the API:

Note: Although there are multiple “Status” functions for each instrument, these functions are the only ones that actually read data from the device.

There are a number of type definitions and corresponding constants in the dwf.h include file. The majority of them are used as parameters. When a hardware device is opened, a handle is returned (HDWF), which is used to access and finally close in all instrument API functions.

The API functions are C style and return a Boolean value: TRUE if the call is successful, FALSE if unsuccessful. This Boolean value is an integer type definition, not the standard c-type bool. In general, the API functions contain variations of the following parameters:

The API functions won’t fail when a parameter pointer is NULL or when a setting (*Set) parameter value is out of limits. To verify the actual setting value, use the *Get API return the actual value.

The supported discrete parameters are retrieved in bit field value. To decode the capabilities of the device use the IsBitSet macro. int fsfilter; FDwfAnalogInChannelFilterInfo(h, &fsfilter) if(IsBitSet(fsfilter, filterAverage)){ FDwfAnalogInChannelFilterSet(hdwf, 0, filterAverage) }

The function above is used to retrieve the last error code in the calling process. The error code is cleared when other API functions are called and is only set when an API function fails during execution. Error codes are declared in dwf.h:

The function above is used to retrieve the last error message. This may consist of a chain of messages, separated by a new line character, that describe the events leading to the failure.

The function above is used to retrieve the version string. The version string is composed of major, minor, and build numbers (i.e. “2.0.19”).

The FDwfEnum functions are used to discover all connected, compatible devices.

Calling the function above will build an internal list of detected devices filtered by the enumfilter parameter. The function above must be called before using other FDwfEnum functions because they obtain information about enumerated devices from this list identified by the device index.

The function above is used to return the device ID and version ID.

The function above is used to retrieve a Boolean specifying if a device is already opened by this, or any other process.

The function above is used to retrieve the user name of the enumerated device. 

The function above is used to retrieve the device name of the enumerated device.

The function above is used to retrieve the 12-digit, unique serial number of the enumerated device.

The function above opens a device identified by the enumeration index and retrieves a handle. To automatically enumerate all connected devices and open the first discovered device, use index -1.

The function above is used to close an interface handle when access to the device is no longer needed. Once the function above has returned, the specified interface handle can no longer be used to access the device.

The function above is used to close all opened devices by the calling process. It does not close all devices across all processes.

The function above enables or disables the AutoConfig setting for a specific device. When this setting is enabled, the device is automatically configured every time an instrument parameter is set. For example, when AutoConfigure is enabled, FDwfAnalogOutConfigure does not need to be called after FDwfAnalogOutRunSet. This adds latency to every Set function; just as much latency as calling the corresponding Configure function directly afterward.

The function above returns the AutoConfig setting in the device. See the function description for FDwfDeviceAutoConfigureSet for details on this setting.

The function above resets and configures all device and instrument parameters to default values.

The function above returns the supported trigger source options for the global trigger bus. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the TRIGSRC constants in dwf.h.

The global trigger bus allows multiple instruments to trigger each other. These trigger source options are:

The function above is used to configure the trigger I/O pin with a specific TRIGSRC option.

The function above returns the configured trigger setting for a trigger I/O pin. The trigger source can be “none”, an internal instrument, or an external trigger.

The function above generates one pulse on the PC trigger line.

The Analog In instrument states:

The states are defined in dwf.h DwfState type.

Ready: Initial state. After FDwfAnalogInConfigure or any FDwfAnalogIn*Set function call goes to this state. With FDwfAnalogInConfigure, reconfigure goes to Configure state.

Configure: The needed configurations are performed and auto trigger is reset.

Prefill: Prefills the buffer with samples needed before trigger.

Armed: Waits for the trigger.

Running:

• Single acquisition mode: remains in this state to acquire samples after trigger according trigger position parameter.
• Scan screen and shift modes: remains in this state until configure or any set function of this instrument.
• Record mode: the time period according record length parameter.

Done: Final state.

The function above resets and configures all AnalogIn instrument parameters to default values. 

The function above is used to configure the instrument and start or stop the acquisition. To reset the Auto trigger timeout, set fReconfigure to TRUE.

The function above is used to check the state of the acquisition. To read the data from the device, set fReadData to TRUE. For single acquisition mode, the data will be read only when the acquisition is finished.

Note: To ensure simultaneity of information and data, all of the following AnalogInStatus* functions do not communicate with the device. These functions only return information and data from the last FDwfAnalogInStatus call.

The function above is used to retrieve the number of samples left in the acquisition.

The function above is used to retrieve the number of valid/acquired data samples.

The function above is used to retrieve the buffer write pointer. This is needed in ScanScreen acquisition mode to display the scan bar.

The function above is used to verify if the acquisition is auto triggered.

The function above is used to retrieve the acquired data samples from the specified idxChannel on the AnalogIn instrument. It copies the data samples to the provided buffer.

The function above gets the last ADC conversion sample from the specified idxChannel on the AnalogIn instrument.

The function above is used to retrieve information about the recording process. The data loss occurs when the device acquisition is faster than the read process to PC. In this case, the device recording buffer is filled and data samples are overwritten. Corrupt samples indicate that the samples have been overwritten by the acquisition process during the previous read. In this case, try optimizing the loop process for faster execution or reduce the acquisition frequency or record length to be less than or equal to the device buffer size (record length ⇐ buffer size/frequency).

The function above is used to set the Record length in seconds.

The function above is used to get the current Record length in seconds.

The function above is used to retrieve the minimum and maximum (ADC frequency) settable sample frequency.

The function above is used to set the sample frequency for the instrument. 

The function above is used to read the configured sample frequency. The AnalogIn ADC always runs at maximum frequency, but the method in which the samples are stored in the buffer can be individually configured for each channel with FDwfAnalogInChannelFilterSet function.

The function above is used to retrieve the number bits used by the AnalogIn ADC.

The function above returns the minimum and maximum allowable buffer sizes for the instrument.

The function above is used to adjust the AnalogIn instrument buffer size.

The function above returns the used AnalogIn instrument buffer size.

The function above returns the supported AnalogIn acquisition modes. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the ACQMODE constants in dwf.h. The acquisition mode selects one of the following modes, ACQMODE:

The function above is used to set the acquisition mode.

The function above is used to get retrieve the acquisition mode. 

The oscilloscope channel settings are identical across all channels.

The function above is used to read the number of AnalogIn channels of the device.

The function above is used to enable or disable the specified AnalogIn channel.

The function above is used to get the current enable/disable status of the specified AnalogIn channel.

The function above returns the supported acquisition filters. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the FILTER constants in dwf.h. When the acquisition frequency (FDwfAnalogInFrequencySet) is less than the ADC frequency (maximum acquisition frequency), the samples can be stored in one of the following ways using FILTER:

• filterDecimate: Store every Nth ADC conversion, where N = ADC frequency /acquisition frequency.
• filterAverage: Store the average of N ADC conversions.
• filterMinMax: Store interleaved, the minimum and maximum values, of 2xN conversions.

The function above is used to set the acquisition filter for each AnalogIn channel. With channel index -1, each enabled AnalogIn channel filter will be configured to use the same, new option.

The function above returns the configured acquisition filter.

The function above returns the minimum and maximum range, peak to peak values, and the number of adjustable steps.

The function above is used to read the range of steps supported by the device. For instance: 1, 2, 5, 10, etc. 

The function above is used to configure the range for each channel. With channel index -1, each enabled Analog In channel range will be configured to the same, new value.

The function above returns the real range value for the given channel.

The function above returns the minimum and maximum offset levels supported, and the number of adjustable steps.

The function above is used to configure the offset for each channel. When channel index is specified as -1, each enabled AnalogIn channel offset will be configured to the same level. 

The function above returns for each AnalogIn channel the real offset level.

The trigger is used for Single and Record acquisitions. For ScanScreen and ScanShift, the trigger is ignored. To achieve the classical trigger types:

• None: Set FDwfAnalogInTriggerSourceSet to trigsrcNone.
• Auto: Set FDwfAnalogInTriggerSourceSet to something other than trigsrcNone, such as trigsrcDetectorAnalogIn and FDwfAnalogInTriggerAutoTimeoutSet to other than zero.
• Normal: Set FDwfAnalogInTriggerSourceSet to something other than trigsrcNone, such as trigsrcDetectorAnalogIn or FDwfAnalogInTriggerAutoTimeoutSet to zero.

The function above returns the supported trigger source options for the AnalogIn instrument. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the TRIGSRC constants in dwf.h. For more detail regarding these constants, see the description of FDwfDeviceTriggerInfo.

The function above is used to configure the AnalogIn acquisition trigger source.

The function above returns the configured trigger source. The trigger source can be “none” or an internal instrument or external trigger. To use the trigger on AnalogIn channels (edge, pulse, etc.), use trigsrcDetectorAnalogIn.

The function above returns the minimum and maximum values of the trigger position in seconds. The horizontal trigger position is used for Single acquisition mode and it is relative to the buffer middle point.

The function above is used to configure the horizontal trigger position in seconds.

The function above returns the configured trigger position in seconds.

The function above returns the minimum and maximum auto trigger timeout values, and the number of adjustable steps. The acquisition is auto triggered when the specified time elapses. With zero value the timeout is disabled, performing “Normal” acquisitions.

The function above is used to configure the auto trigger timeout value in seconds.

The function above returns the configured auto trigger timeout value in seconds.

The function above returns the supported range of the trigger Hold-Off time in Seconds. The trigger hold-off is an adjustable period of time during which the acquisition will not trigger. This feature is used when you are triggering on burst waveform shapes, so the oscilloscope triggers only on the first eligible trigger point. 

The function above is used to set the trigger hold-off for the AnalongIn instrument in Seconds.

The function above is used to get the current trigger hold-off for the AnalongIn instrument in Seconds.

The following functions configure the trigger detector on analog in channels. To use this set trigger source with FDwfAnalogInTriggerSourceSet to trigsrcDetectorAnalogIn.

The function above returns the supported trigger type options for the instrument. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the TRIGTYPE constants in dwf.h. These trigger type options are:

• trigtypeEdge: trigger on rising or falling edge. This is the default setting.
• trigtypePulse: trigger on positive or negative; less, timeout or more pulse lengths
• trigtypeTransition: trigger on rising or falling; less, timeout or more transition times

The function above is used to set the trigger type for the instrument.

The function above is used to get the current trigger type for the instrument.

The function above returns the range of channels that can be triggered on.

The function above is used to set the trigger channel.

The function above is used to retrieve the current trigger channel index. 

The function above returns the supported trigger filters. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the FILTER constants in DWF.h. Select trigger detector sample source, FILTER:

• filterDecimate: Looks for trigger in each ADC conversion, can detect glitches.
• filterAverage: Looks for trigger only in average of N samples, given by FDwfAnalogInFrequencySet.

The function above is used to set the trigger filter.

The function above is used to get the trigger filter.

The function above returns the supported trigger type options for the instrument. They are returned (by reference) as a bit field. This bit field can be parsed using the IsBitSet Macro. Individual bits are defined using the TRIGCOND constants in dwf.h. These trigger condition options are:

trigcondRisingPositive (This is the default setting):

• For edge and transition trigger on rising edge.
• For pulse trigger on positive pulse.

trigcondFallingNegative:

• For edge and transition trigger on falling edge.
• For pulse trigger on negative pulse.

The function above is used to set the trigger condition for the instrument.

The function above is used to set the trigger condition for the instrument.

The function above is used to retrieve the range of valid trigger voltage levels for the AnalogIn instrument in Volts.

The function above is used to set the trigger voltage level in Volts.