Reloadable Coefficients - update_rtp() method - 2025.2 English

An ease of use enhancements with update_rtp() method is available for each FIR graph class. Method simplifies the process of updating coefficients at runtime to a single method call.

The example below demonstrates how to use the update_rtp() method in the context of a FIR filter graph class.

The test_graph class contains a member firGraph, which is a parameterized fir_sr_asym_graph FIR filter graph. The test_graph class also contains an array of coefficient RTP ports. Size of the array is determined by the getTotalRtpPorts() method of the fir_sr_asym_graph class.

The main function of the host application initializes the graph, updates the RTP ports at runtime using update_rtp with coefficients values from the std::vector taps.

Next, the main function runs the filter for a specified number of iterations and properly ends the graph execution.

// This is a header file, e.g. "test.hpp" that is included in the corresponding cpp file.

class test_graph : public adf::graph {
public:

xf::dsp::aie::fir::tdm::fir_tdm_graph<
   cint16, //TT_DATA
   int16, //TT_COEFF
   4, //TP_FIR_LEN
   10, //TP_SHIFT
   0, //TP_RND
   128, //TP_INPUT_WINDOW_VSIZE
   32, //TP_TDM_CHANNELS
   1, //TP_NUM_OUTPUTS
   0, //TP_DUAL_IP
   // 0, //TP_API
   1, //TP_SSR
   0, //TP_SAT
   1, //TP_CASC_LEN
   cint32 //TT_OUT_DATA
> firGraph;

static constexpr int rtpPortNumber = firGraph::getTotalRtpPorts();
port_array<input, rtpPortNumber> coeff;

#include "test.hpp"

xf::dsp::aie::testcase::test_graph filter;

int main(void) {
   filter.init();

   std::vector<int16> taps = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63};

   filter.firGraph.update_rtp(filter, taps, filter.coeff);

   filter.run(4);

   filter.end();

   return 0;
}

The update_rtp is a simple to use method that abstracts the implementation details of updating RTP ports with new coefficient values. It performs the following steps:

• read total number of rtp ports, using getTotalRtpPorts(). For details see Reloadable Coefficients - Number of ports.
• for each port, read the size of the port, using getRtpPortSize(int port). For details see Reloadable Coefficients - Array Size.
• for each port, extract the corresponding taps using the extractTaps() method. For details see Reloadable Coefficients - Array Contents.
• for each port, update the RTP port with the new taps using the graphs update() method. For details see UG1079 Run-Time Parameter Update/Read Mechanisms.