140 lines
6.5 KiB
C
140 lines
6.5 KiB
C
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// #################################################################################################
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// # << NEORV32 - Watchdog Demo Program >> #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # #
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// # Copyright (c) 2023, 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_wdt/main.c
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* @author Stephan Nolting
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* @brief Watchdog 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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/** WDT timeout (until system reset) in seconds */
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#define WDT_TIMEOUT_S 4
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/**@}*/
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/**********************************************************************//**
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* Watchdog FIRQ handler - executed when the WDT has reached half of
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* the configured timeout interval.
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**************************************************************************/
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void wdt_firq_handler(void) {
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neorv32_cpu_csr_write(CSR_MIP, ~(1<<WDT_FIRQ_PENDING)); // clear/ack pending FIRQ
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neorv32_uart0_puts("WDT IRQ! Timeout imminent!\n");
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}
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/**********************************************************************//**
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* Main function
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*
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* @note This program requires the WDT and UART0 to be synthesized.
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*
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* @return 0 if execution was successful
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**************************************************************************/
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int main() {
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// setup NEORV32 runtime environment for capturing all traps
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neorv32_rte_setup();
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// setup UART0 at default baud rate, no parity bits, ho HW flow control
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neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);
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// check if WDT is implemented at all
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if (neorv32_wdt_available() == 0) {
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return 1; // WDT not synthesized
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}
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// check if UART0 is implemented at all
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if (neorv32_uart0_available() == 0) {
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return 1; // UART0 not synthesized
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}
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// intro
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neorv32_uart0_puts("\n<< Watchdog Demo Program >>\n\n");
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// show the cause of the last processor reset
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neorv32_uart0_puts("Cause of last processor reset: ");
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if (neorv32_wdt_get_cause() == 0) {
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neorv32_uart0_puts("External reset\n\n");
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}
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else {
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neorv32_uart0_puts("Watchdog timeout\n\n");
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}
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// configure and enable WDT interrupt
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// this IRQ will trigger when half of the configured WDT timeout interval has been reached
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neorv32_uart0_puts("Configuring WDT interrupt...\n");
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neorv32_rte_handler_install(WDT_RTE_ID, wdt_firq_handler);
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neorv32_cpu_csr_set(CSR_MIE, 1 << WDT_FIRQ_ENABLE); // enable WDT FIRQ channel
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neorv32_cpu_csr_set(CSR_MSTATUS, 1 << CSR_MSTATUS_MIE); // enable machine-mode interrupts
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// compute WDT timeout value
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// - the WDT counter increments at f_wdt = f_main / 4096
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uint32_t timeout = WDT_TIMEOUT_S * (NEORV32_SYSINFO.CLK / 4096);
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if (timeout & 0xFF000000U) { // check if timeout value fits into 24-bit
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neorv32_uart0_puts("Timeout value does not fit into 24-bit!\n");
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return -1;
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}
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// setup watchdog: no lock, disable in debug mode, enable in sleep mode
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neorv32_uart0_puts("Starting WDT...\n");
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neorv32_wdt_setup(timeout, 0, 0, 1);
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// feed the watchdog
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neorv32_uart0_puts("Resetting WDT...\n");
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neorv32_wdt_feed(); // reset internal counter to zero
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// go to sleep mode and wait for watchdog to kick in
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neorv32_uart0_puts("Entering sleep mode and waiting for WDT timeout...\n");
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while(1) {
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neorv32_cpu_sleep();
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}
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return 0; // will never be reached
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}
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