neorv32/sw/example/demo_wdt/main.c

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2024-02-24 08:25:27 +00:00
// #################################################################################################
// # << NEORV32 - Watchdog Demo Program >> #
// # ********************************************************************************************* #
// # BSD 3-Clause License #
// # #
// # Copyright (c) 2023, 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_wdt/main.c
* @author Stephan Nolting
* @brief Watchdog demo program.
**************************************************************************/
#include <neorv32.h>
/**********************************************************************//**
* @name User configuration
**************************************************************************/
/**@{*/
/** UART BAUD rate */
#define BAUD_RATE 19200
/** WDT timeout (until system reset) in seconds */
#define WDT_TIMEOUT_S 8
/**@}*/
/**********************************************************************//**
* Watchdog FIRQ handler - executed when the WDT has reached half of
* the configured timeout interval.
**************************************************************************/
void wdt_firq_handler(void) {
neorv32_cpu_csr_clr(CSR_MIP, 1<<WDT_FIRQ_PENDING); // clear/ack pending FIRQ
neorv32_uart0_puts("WDT IRQ! Timeout imminent!\n");
}
/**********************************************************************//**
* Main function
*
* @note This program requires the WDT and UART0 to be synthesized.
*
* @return 0 if execution was successful
**************************************************************************/
int main() {
// setup NEORV32 runtime environment for capturing all traps
neorv32_rte_setup();
// setup UART at default baud rate, no interrupts
neorv32_uart0_setup(BAUD_RATE, 0);
// check if WDT is implemented at all
if (neorv32_wdt_available() == 0) {
return 1; // WDT not synthesized
}
// check if UART0 is implemented at all
if (neorv32_uart0_available() == 0) {
return 1; // UART0 not synthesized
}
// intro
neorv32_uart0_puts("\n<< Watchdog Demo Program >>\n\n");
// show the cause of the last processor reset
neorv32_uart0_puts("Cause of last processor reset: ");
if (neorv32_wdt_get_cause() == WDT_RCAUSE_EXT) {
neorv32_uart0_puts("External reset\n\n");
}
else if (neorv32_wdt_get_cause() == WDT_RCAUSE_OCD) {
neorv32_uart0_puts("On-chip debugger reset\n\n");
}
else if (neorv32_wdt_get_cause() == WDT_RCAUSE_WDT) {
neorv32_uart0_puts("Watchdog reset\n\n");
}
else {
neorv32_uart0_puts("Unknown\n\n");
}
// configure and enable WDT interrupt
// this IRQ will trigger when half of the configured WDT timeout interval has been reached
neorv32_uart0_puts("Configuring WDT interrupt...\n");
neorv32_rte_handler_install(WDT_RTE_ID, wdt_firq_handler);
neorv32_cpu_csr_set(CSR_MIE, 1 << WDT_FIRQ_ENABLE); // enable WDT FIRQ channel
neorv32_cpu_csr_set(CSR_MSTATUS, 1 << CSR_MSTATUS_MIE); // enable machine-mode interrupts
// compute WDT timeout value
// - the WDT counter increments at f_wdt = f_main / 4096
uint32_t timeout = WDT_TIMEOUT_S * (NEORV32_SYSINFO->CLK / 4096);
if (timeout & 0xFF000000U) { // check if timeout value fits into 24-bit
neorv32_uart0_puts("Timeout value does not fit into 24-bit!\n");
return -1;
}
// setup watchdog: no lock, disable in debug mode, enable in sleep mode, enable strict password check
neorv32_uart0_puts("Starting WDT...\n");
neorv32_wdt_setup(timeout, 0, 0, 1, 1);
// feed the watchdog
neorv32_uart0_puts("Resetting WDT 5 times...\n");
int i;
for (i=0; i<5; i++) {
neorv32_cpu_delay_ms(750);
neorv32_wdt_feed(); // reset internal counter to zero
neorv32_uart0_puts("WDT reset.\n");
}
// go to sleep mode and wait for watchdog to kick in
neorv32_uart0_puts("Entering sleep mode and waiting for WDT timeout...\n");
while(1) {
neorv32_cpu_sleep();
}
return 0; // will never be reached
}