167 lines
6.4 KiB
C
167 lines
6.4 KiB
C
// #################################################################################################
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// # << NEORV32 - PWM Demo Program >> #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # #
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// # Copyright (c) 2022, Stephan Nolting. All rights reserved. #
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// # #
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// # Redistribution and use in source and binary forms, with or without modification, are #
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// # permitted provided that the following conditions are met: #
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// # #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of #
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// # conditions and the following disclaimer. #
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// # #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
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// # conditions and the following disclaimer in the documentation and/or other materials #
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// # provided with the distribution. #
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// # #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
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// # endorse or promote products derived from this software without specific prior written #
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// # permission. #
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// # #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
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// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
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// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
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// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
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// # OF THE POSSIBILITY OF SUCH DAMAGE. #
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// # ********************************************************************************************* #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
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// #################################################################################################
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/**********************************************************************//**
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* @file demo_pwm/main.c
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* @author Stephan Nolting
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* @brief Simple PWM demo program.
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**************************************************************************/
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#include <neorv32.h>
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/**********************************************************************//**
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* @name User configuration
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**************************************************************************/
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/**@{*/
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/** UART BAUD rate */
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#define BAUD_RATE 19200
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/** Maximum PWM output intensity (0..255) */
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#define PWM_MAX 128
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/**@}*/
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/**********************************************************************//**
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* Helper function to count the number of implemented PWM channels.
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*
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* @return Number of available PWM channels (0..60)
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**************************************************************************/
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int aux_get_pwm_num_channels(void) {
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if (neorv32_pwm_available() == 0) {
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return 0;
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}
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int i = 0;
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uint32_t tmp = 0;
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NEORV32_PWM.CTRL = 0; // disable PWM controller
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for (i=0; i<15; i++) {
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NEORV32_PWM.DUTY[i] = 0x01010101; // try to set all possible DUTY cycle values
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}
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for (i=0; i<15; i++) {
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tmp += NEORV32_PWM.DUTY[i]; // read back
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}
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// add four byte subwords
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tmp = ((tmp >> 0) & 0xff) + ((tmp >> 8) & 0xff) + ((tmp >> 16) & 0xff) + ((tmp >> 24) & 0xff);
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return (int)(tmp & 0xff);
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}
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/**********************************************************************//**
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* This program generates a simple dimming sequence for PWM channels 0 to 3.
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*
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* @note This program requires the PWM controller to be synthesized (the UART is optional).
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*
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* @return !=0 if error.
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**************************************************************************/
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int main() {
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// capture all exceptions and give debug info via UART
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// this is not required, but keeps us safe
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neorv32_rte_setup();
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// use UART0 if implemented
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if (neorv32_uart0_available()) {
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// init UART at default baud rate, no parity bits, no hw flow control
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neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);
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// say hello
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neorv32_uart0_printf("PWM demo program\n");
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}
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// check if PWM unit is implemented at all
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if (neorv32_pwm_available() == 0) {
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if (neorv32_uart0_available()) {
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neorv32_uart0_printf("ERROR: PWM module not implemented!\n");
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}
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return 1;
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}
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int num_pwm_channels = aux_get_pwm_num_channels();
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// check number of PWM channels
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if (neorv32_uart0_available()) {
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neorv32_uart0_printf("Implemented PWM channels: %i\n\n", num_pwm_channels);
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}
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// deactivate all PWM channels
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int i;
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for (i=0; i<num_pwm_channels; i++) {
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neorv32_pwm_set(i, 0);
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}
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// configure and enable PWM
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neorv32_pwm_setup(CLK_PRSC_64);
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uint8_t pwm = 0;
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uint8_t up = 1;
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uint8_t ch = 0;
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// animate!
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while(1) {
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// update duty cycle
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if (up) {
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if (pwm == (PWM_MAX & 0xFF)) {
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up = 0;
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}
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else {
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pwm++;
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}
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}
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else {
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if (pwm == 0) {
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ch = (ch + 1) & 3; // goto next channel
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up = 1;
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}
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else {
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pwm--;
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}
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}
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neorv32_pwm_set(ch, pwm); // output new duty cycle
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neorv32_cpu_delay_ms(5); // wait ~5ms
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}
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return 0;
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}
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