/** * Copyright (c) 2024 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include <stdio.h> #include "pico/stdlib.h" #include <math.h> /* NOTE: the example code here does not check the DCP's engaged flag. It is therefore not suitable for use in multi-threaded applications or in interrupt service routines. See the device datasheet for more information. */ /// \tag::hello_dcp[] extern double dcp_dot (double*p,double*q,int n); extern double dcp_dotx (float*p,float*q,int n); extern float dcp_iirx (float x,float*temp,float*coeff,int order); extern void dcp_butterfly_radix2 (double*x,double*y); extern void dcp_butterfly_radix2_twiddle_dif (double*x,double*y,double*tf); extern void dcp_butterfly_radix2_twiddle_dit (double*x,double*y,double*tf); extern void dcp_butterfly_radix4 (double*w,double*x,double*y,double*z); static void dcp_test0() { double u[3]={1,2,3}; double v[3]={4,5,6}; double w; w=dcp_dot(u,v,3); printf("(1,2,3).(4,5,6)=%g\n",w); } static void dcp_test1() { float u[3]={1+pow(2,-20),2,3}; float v[3]={1-pow(2,-20),5,6}; double w; w=dcp_dotx(u,v,3); printf("(1+pow(2,-20),2,3).(1-pow(2,-20),5,6)=%.17g\n",w); } static void dcp_test2() { int t; float w; // filter coefficients calculated using Octave as follows: // octave> pkg load signal // octave> format long // octave> [b,a]=cheby1(2,1,.5) // b = 0.307043201259064 0.614086402518128 0.307043201259064 // a = 1.000000000000000e+00 6.406405700380895e-02 3.139684953186774e-01 // and tested as follows: // octave> filter(b,a,[1 zeros(1,19)]) float coeff[5]={0.3070432,0.3139685,0.6140864,0.06406406,0.3070432}; float temp[4]={0}; printf("IIR filter impulse response:\n"); for(t=0;t<20;t++) { w=dcp_iirx(t?0:1,temp,coeff,2); printf("y[%2d]=%g\n",t,w); } } static void dcp_test3() { double x[2]={2,3}; double y[2]={5,7}; dcp_butterfly_radix2(x,y); printf("Radix-2 butterfly of (2+3j,5+7j)=(%g%+gj,%g%+gj)\n",x[0],x[1],y[0],y[1]); } static void dcp_test4() { double x[2]={2,3}; double y[2]={5,7}; double t[2]={1.5,2.5}; dcp_butterfly_radix2_twiddle_dif(x,y,t); printf("Radix-2 DIF butterfly of (2+3j,5+7j) with twiddle factor (1.5+2.5j)=(%g%+gj,%g%+gj)\n",x[0],x[1],y[0],y[1]); } static void dcp_test5() { double x[2]={2,3}; double y[2]={5,7}; double t[2]={1.5,2.5}; dcp_butterfly_radix2_twiddle_dit(x,y,t); printf("Radix-2 DIT butterfly of (2+3j,5+7j) with twiddle factor (1.5+2.5j)=(%g%+gj,%g%+gj)\n",x[0],x[1],y[0],y[1]); } static void dcp_test6() { double w[2]={2,3}; double x[2]={5,7}; double y[2]={11,17}; double z[2]={41,43}; dcp_butterfly_radix4(w,x,y,z); printf("Radix-4 butterfly of (2+3j,5+7j,11+17j,41+43j)=(%g%+gj,%g%+gj,%g%+gj,%g%+gj)\n",w[0],w[1],x[0],x[1],y[0],y[1],z[0],z[1]); } int main() { stdio_init_all(); printf("Hello, DCP!\n"); dcp_test0(); dcp_test1(); dcp_test2(); dcp_test3(); dcp_test4(); dcp_test5(); dcp_test6(); return 0; } /// \end::hello_dcp[]

This firmware image was imported from the pico-examples repository. 


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