01604acc51
This adds a basic example demonstrating how to enable and use the CMSIS-DSP module in Zephyr. Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
/*
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* Copyright (c) 2024 Benjamin Cabé <benjamin@zephyrproject.org>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <stdio.h>
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#include <zephyr/kernel.h>
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#include "arm_math.h"
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#define NUM_TAPS 10 /* Number of taps in the FIR filter (length of the moving average window) */
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#define BLOCK_SIZE 32 /* Number of samples processed per block */
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/*
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* Filter coefficients are all equal for a moving average filter. Here, 1/NUM_TAPS = 0.1f.
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*/
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q31_t firCoeffs[NUM_TAPS] = {0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD,
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0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD, 0x0CCCCCCD};
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arm_fir_instance_q31 sFIR;
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q31_t firState[NUM_TAPS + BLOCK_SIZE - 1];
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int main(void)
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{
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q31_t input[BLOCK_SIZE];
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q31_t output[BLOCK_SIZE];
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uint32_t start, end;
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/* Initialize input data with a ramp from 0 to 31 */
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for (int i = 0; i < BLOCK_SIZE; i++) {
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input[i] = i << 24; /* Convert to Q31 format */
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}
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/* Initialize the FIR filter */
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arm_fir_init_q31(&sFIR, NUM_TAPS, firCoeffs, firState, BLOCK_SIZE);
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/* Apply the FIR filter to the input data and measure how many cycles this takes */
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start = k_cycle_get_32();
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arm_fir_q31(&sFIR, input, output, BLOCK_SIZE);
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end = k_cycle_get_32();
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printf("Time: %u us (%u cycles)\n", k_cyc_to_us_floor32(end - start), end - start);
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for (int i = 0; i < BLOCK_SIZE; i++) {
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printf("Input[%02d]: ", i);
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for (int j = NUM_TAPS - 1; j >= 0; j--) {
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if (j <= i) {
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printf("%2d ", (int)(input[i - j] >> 24));
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} else {
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printf("%2d ", 0);
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}
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}
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printf("| Output[%02d]: %6.2f\n", i, (double)output[i] / (1 << 24));
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}
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return 0;
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}
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