Overview - 2024.2 English

describes the type of individual data samples input to the transform function.

This is a typename and must be one of the following:

cint16, cint32, cfloat. For real-only operation, consider use of the widget_real2complex library element.

is an unsigned integer which describes the number of samples in the transform.

This must be 2^N where N is an integer in the range 4 to 16 inclusive.

When TP_DYN_PT_SIZE is set, TP_POINT_SIZE describes the maximum point size possible.

selects whether (1) or not (0) to use run-time point size determination.

When set, each window of data must be preceeded, in the window, by a 256 bit header.

This header is 8 samples when TT_DATA is cint16 and 4 samples otherwise.

The real part of the first sample indicates the forward (1) or inverse (0) transform.

The real part of the second sample indicates the Radix2 power of the point size.

e.g. for a 512 point size, this field would hold 9, as 2^9 = 512. Any value below 4 or greater than log2(TP_POINT_SIZE) is considered illegal.

The output window will also be preceeded by a 256 bit vector which is a copy of the input

vector, but for the real part of the top sample, which is 0 to indicate a legal frame or 1 to

indicate an illegal frame.

When TP_PARALLEL_POWER is greater than 0, the header must be applied before each window of data

for every port of the design and will appears before each window of data on the output ports.

Note that the minimum point size of 16 applies to each lane when in parallel mode, so a configuration

of point size 256 with TP_PARALLEL_POWER = 2 will have 4 lanes each with a minimum of 16 so the minimum

legal point size here is 64.

is an unsigned integer to select window (0) or stream (1) interfaces.

When stream I/O is selected, one sample is taken from, or output to, a stream and the next sample from or two the next stream. Two streams minimum are used. In this example, even samples are read from input stream[0] and odd samples from input stream[1].

is an unsigned integer to control the use of widgets for configurations which either use TP_API=1 or TP_PARALLEL_POWER>0.

Designs with streaming IO (TP_API=1) and/or multiple subframe processors (TP_PARALLEL_POWER>0) will use streams internally, even if not externally.

The default is not to use widgets but to have the stream to window conversion performed as part of the FFT kernel or R2combiner kernel. Using widget kernels allows this conversion to be placed in a separate tile and so boost performance at the expense of more tiles being used.

describes the selection of saturation to be applied during the shift down stage of processing.

TP_SAT accepts unsigned integer values, where:

• 0: none = No saturation is performed and the value is simply cropped (aliased).
• 1: saturate = Default. Saturation rounds an n-bit signed value in the range [- ( 2^(n-1) ) : +2^(n-1) - 1 ].
• 3: symmetric = Controls symmetric saturation. Symmetric saturation rounds an n-bit signed value in the *range [- ( 2^(n-1) -1 ) : +2^(n-1) - 1 ].

describes the type of individual data samples output from the transform function.

This is a typename and must be cint16 / cint32 if TT_DATA is cint16 / cint32 or cfloat if TT_DATA is cfloat. For real-only operation, consider use of the widget_real2complex library element.

This parameter is for internal use regarding the recursion of the parallel power feature.

It is recommended to miss this parameter from the configuration and rely instead on default values. If this parameter is set by the user, the behaviour of the library unit is undefined.