lora-car/libopencm3/lib/swm050/wdt.c
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2023-01-21 21:54:42 +02:00

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C

/** @defgroup wdg_file Watchdog peripheral API
* @brief SWM050 WDT API.
* @ingroup peripheral_apis
* LGPL License Terms @ref lgpl_license
* @author @htmlonly © @endhtmlonly 2019
* Caleb Szalacinski <contact@skiboy.net>
*/
/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2019 Caleb Szalacinski <contact@skiboy.net>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/**@{*/
#include <libopencm3/swm050/wdt.h>
#include <libopencm3/swm050/sysctl.h>
/**
* Sets up the WDT before the call to @ref wdt_enable().
* This only prepares the watchdog, it will not start counting until
* it is enabled.
* @param mode passed to @ref wdt_mode()
* @param time1 passed to @ref wdt_set_time()
* @param time2 passed to @ref wdt_set_time()
*/
void wdt_setup(enum wdt_modes mode, uint8_t time1, uint8_t time2)
{
wdt_clock_enable(1);
wdt_set_time(time1, time2);
wdt_mode(mode);
wdt_reset();
}
/**
* Enables the WDT.
* This actually starts the watchdog, you should have already selected
* modes and set timeouts.
* If @ref WDT_MODE_INT is used, the interrupt should also be enabled
* using the NVIC before enabling the WDT.
* @sa wdt_setup
* @param en enable
*/
void wdt_enable(bool en)
{
if (en) {
WDT_CR |= 0x1;
} else {
WDT_CR &= ~0x1;
}
}
/**
* Sets the WDT's mode of operation.
* @param mode The mode of operation @ref wdt_modes
*/
void wdt_mode(enum wdt_modes mode)
{
if (mode == WDT_MODE_INT) {
WDT_CR |= (1 << 1);
} else {
WDT_CR &= ~(1 << 1);
}
}
/**
* Reset the WDT's counter.
* The "feed the dog" operation. Must be called periodically to avoid a
* timeout. Calling this also clears any WDT interrupts.
*/
void wdt_reset(void)
{
WDT_CRR = 0x76;
}
/**
* Gets the WDT's interrupt status.
* @note Only useful with @ref WDT_MODE_INT
* @return The WDT's interrupt status. True if an interrupt has not been cleared.
*/
bool wdt_int_status(void)
{
return WDT_STAT & 0x1;
}
/**
* Clears the WDT's interrupt.
* @note Only useful with @ref WDT_MODE_INT
*/
void wdt_clear_int(void)
{
/* Read register to clear the interrupt */
uint32_t dummy = WDT_EOI;
/* Does nothing, but suppresses a -Wunused-variable warning */
(void)dummy;
}
/**
* Enables the WDT's clock.
* This only enables the clock to the peripheral.
* @sa wdt_setup
* @param en True to enable, false to disable
*/
void wdt_clock_enable(bool en)
{
if (en) {
SYSCTL_SYS_CFG_1 |= SYSCTL_SYS_CFG_1_WDT;
} else {
SYSCTL_SYS_CFG_1 &= ~SYSCTL_SYS_CFG_1_WDT;
}
}
/**
* Gets the current WDT counter value.
* The vendor-supplied documentation for the @ref WDT_CCVR register appears to be
* incorrect, and does not seem to be 1 bit wide, which would make no sense.
* @return The current WDT counter value
*/
uint32_t wdt_get_value(void)
{
return WDT_CCVR;
}
/**
* Sets the WDT's initial counter values.
* Both time1 and time2 follow the equation 2^(8 + i), where i is a value from
* 0 to 15, and where the result is in clock cycles.
* For example:
* time1 = 15
* 2^(8 + time1) / 18Mhz = 0.466s
* The majority of the vendor-supplied documentation appears to be completely
* incorrect about the equation used for these counters.
*
* Only the least significant 4 bits are used for both values, eg 0 to 15.
*
* @param time1 The timer value used in both modes. In @ref WDT_MODE_RESET, this
* value counts down to 0 and resets the system. In @ref WDT_MODE_INT, this value
* counts down to 0, generates a WDT interrupt, loads time2 into the counter,
* and counts down.
* @param time2 The timer value used after time1 in mode @ref WDT_MODE_INT. If
* this counts down to 0, and the WDT interrupt has not been cleared, the
* system resets. This has no use in mode @ref WDT_MODE_RESET.
*/
void wdt_set_time(uint8_t time1, uint8_t time2)
{
WDT_TORR = ((0xF & time1) << 4) | (0xF & time2);
}
/**@}*/