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[/] [neorv32/] [trunk/] [sw/] [example/] [demo_pwm/] [main.c] - Rev 67
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// ################################################################################################# // # << NEORV32 - PWM Demo Program >> # // # ********************************************************************************************* # // # BSD 3-Clause License # // # # // # Copyright (c) 2021, Stephan Nolting. All rights reserved. # // # # // # Redistribution and use in source and binary forms, with or without modification, are # // # permitted provided that the following conditions are met: # // # # // # 1. Redistributions of source code must retain the above copyright notice, this list of # // # conditions and the following disclaimer. # // # # // # 2. Redistributions in binary form must reproduce the above copyright notice, this list of # // # conditions and the following disclaimer in the documentation and/or other materials # // # provided with the distribution. # // # # // # 3. Neither the name of the copyright holder nor the names of its contributors may be used to # // # endorse or promote products derived from this software without specific prior written # // # permission. # // # # // # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS # // # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF # // # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE # // # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, # // # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE # // # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED # // # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # // # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED # // # OF THE POSSIBILITY OF SUCH DAMAGE. # // # ********************************************************************************************* # // # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting # // ################################################################################################# /**********************************************************************//** * @file demo_pwm/main.c * @author Stephan Nolting * @brief Simple PWM usage example. **************************************************************************/ #include <neorv32.h> /**********************************************************************//** * @name User configuration **************************************************************************/ /**@{*/ /** UART BAUD rate */ #define BAUD_RATE 19200 /** Maximum PWM output intensity (0..255) */ #define PWM_MAX 128 /**@}*/ /**********************************************************************//** * This program generates a simple dimming sequence for PWM channel 0,1,2. * * @note This program requires the PWM controller to be synthesized (the UART is optional). * * @return 0 if execution was successful **************************************************************************/ int main() { // check if PWM unit is implemented at all if (neorv32_pwm_available() == 0) { return 1; } // capture all exceptions and give debug info via UART // this is not required, but keeps us safe neorv32_rte_setup(); // use UART0 if implemented if (neorv32_uart0_available()) { // init UART at default baud rate, no parity bits, ho hw flow control neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE); // check available hardware extensions and compare with compiler flags neorv32_rte_check_isa(0); // silent = 0 -> show message if isa mismatch // say hello neorv32_uart0_print("PWM demo program\n"); } // deactivate all PWM channels neorv32_pwm_set(0, 0); neorv32_pwm_set(1, 0); neorv32_pwm_set(2, 0); neorv32_pwm_set(3, 0); // configure and enable PWM neorv32_pwm_setup(CLK_PRSC_64); uint8_t pwm = 0; uint8_t up = 1; uint8_t ch = 0; // animate! while(1) { // update duty cycle if (up) { if (pwm == (PWM_MAX & 0xFF)) { up = 0; } else { pwm++; } } else { if (pwm == 0) { ch = (ch + 1) & 3; // goto next channel up = 1; } else { pwm--; } } // output new duty cycle if (ch != 3) { // skip channel 3 neorv32_pwm_set(ch, pwm); } neorv32_cpu_delay_ms(10); // wait ~10ms } return 0; }
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