122 lines
6.0 KiB
C
122 lines
6.0 KiB
C
// #################################################################################################
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// # << NEORV32 - General Purpose Timer (GPTMR) Demo Program >> #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # #
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// # Copyright (c) 2024, 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_gptmr/main.c
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* @author Stephan Nolting
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* @brief Simple GPTMR timer-match interrupt example.
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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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/**@}*/
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// Prototypes
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void gptmr_firq_handler(void);
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/**********************************************************************//**
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* This program blinks an LED at GPIO.output(0) at 1Hz using the general purpose timer interrupt.
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*
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* @note This program requires the GPTMR unit to be synthesized (and UART0 and GPIO).
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*
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* @return Should not return;
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**************************************************************************/
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int main() {
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// setup NEORV32 runtime environment (for trap handling)
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neorv32_rte_setup();
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// setup UART at default baud rate, no interrupts
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neorv32_uart0_setup(BAUD_RATE, 0);
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// check if GPTMR unit is implemented at all
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if (neorv32_gptmr_available() == 0) {
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neorv32_uart0_puts("ERROR! General purpose timer not implemented!\n");
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return 1;
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}
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// Intro
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neorv32_uart0_puts("General purpose timer (GPTMR) demo Program.\n"
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"Toggles GPIO.output(0) at 1Hz using the GPTMR timer-match interrupt.\n\n");
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// clear GPIO output port
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neorv32_gpio_port_set(0);
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// install GPTMR interrupt handler
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neorv32_rte_handler_install(GPTMR_RTE_ID, gptmr_firq_handler);
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// configure timer for 1Hz ticks with clock divisor = 8 and enable timer-match interrupt
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neorv32_gptmr_setup(CLK_PRSC_8, NEORV32_SYSINFO->CLK / (8 * 2), 1);
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// enable interrupt
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neorv32_cpu_csr_clr(CSR_MIP, 1 << GPTMR_FIRQ_PENDING); // make sure there is no GPTMR IRQ pending already
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neorv32_cpu_csr_set(CSR_MIE, 1 << GPTMR_FIRQ_ENABLE); // enable GPTMR FIRQ channel
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neorv32_cpu_csr_set(CSR_MSTATUS, 1 << CSR_MSTATUS_MIE); // enable machine-mode interrupts
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// go to sleep mode and wait for interrupt
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while(1) {
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neorv32_cpu_sleep();
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}
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return 0;
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}
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/**********************************************************************//**
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* GPTMR FIRQ handler.
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*
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* @warning This function has to be of type "void xyz(void)" and must not use any interrupt attributes!
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**************************************************************************/
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void gptmr_firq_handler(void) {
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neorv32_cpu_csr_write(CSR_MIP, ~(1<<GPTMR_FIRQ_PENDING)); // clear/ack pending FIRQ
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neorv32_uart0_putc('.'); // send tick symbol via UART0
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neorv32_gpio_pin_toggle(0); // toggle output port bit 0
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}
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