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wwdt.c
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1 /*
2 * @brief Windowed Watchdog Timer (WWDT) example
3 *
4 * @note
5 * Copyright(C) NXP Semiconductors, 2012
6 * All rights reserved.
7 *
8 * @par
9 * Software that is described herein is for illustrative purposes only
10 * which provides customers with programming information regarding the
11 * LPC products. This software is supplied "AS IS" without any warranties of
12 * any kind, and NXP Semiconductors and its licensor disclaim any and
13 * all warranties, express or implied, including all implied warranties of
14 * merchantability, fitness for a particular purpose and non-infringement of
15 * intellectual property rights. NXP Semiconductors assumes no responsibility
16 * or liability for the use of the software, conveys no license or rights under any
17 * patent, copyright, mask work right, or any other intellectual property rights in
18 * or to any products. NXP Semiconductors reserves the right to make changes
19 * in the software without notification. NXP Semiconductors also makes no
20 * representation or warranty that such application will be suitable for the
21 * specified use without further testing or modification.
22 *
23 * @par
24 * Permission to use, copy, modify, and distribute this software and its
25 * documentation is hereby granted, under NXP Semiconductors' and its
26 * licensor's relevant copyrights in the software, without fee, provided that it
27 * is used in conjunction with NXP Semiconductors microcontrollers. This
28 * copyright, permission, and disclaimer notice must appear in all copies of
29 * this code.
30 */
31
32 #include "board.h"
33
58 /*****************************************************************************
59 * Private types/enumerations/variables
60 ****************************************************************************/
61
62 /*****************************************************************************
63 * Public types/enumerations/variables
64 ****************************************************************************/
65
66 /*****************************************************************************
67 * Private functions
68 ****************************************************************************/
69
70 /*****************************************************************************
71 * Public functions
72 ****************************************************************************/
78 void WDT_IRQHandler(void)
79 {
80 uint32_t wdtStatus = Chip_WWDT_GetStatus(LPC_WWDT);
81
82 Board_LED_Toggle(0);
83
84 /* The chip will reset before this happens, but if the WDT doesn't
85 have WWDT_WDMOD_WDRESET enabled, this will hit once */
86 if (wdtStatus & WWDT_WDMOD_WDTOF) {
87 /* A watchdog feed didn't occur prior to window timeout */
88 Chip_WWDT_UnsetOption(LPC_WWDT, WWDT_WDMOD_WDEN); /* Stop WDT */
89 Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDTOF);
90 Chip_WWDT_Start(LPC_WWDT); /* Needs restart */
91 }
92
93 /* Handle warning interrupt */
94 if (wdtStatus & WWDT_WDMOD_WDINT) {
95 /* A watchdog feed didn't occur prior to warning timeout */
96 Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDINT);
97 Chip_WWDT_Feed(LPC_WWDT);
98 }
99 }
100
105 int main(void)
106 {
107 uint32_t wdtFreq;
108
109 Board_Init();
110
111 /* Freq = 0.6Mhz, divided by 64. WDT_OSC should be 9.375khz */
112 Chip_Clock_SetWDTOSC(WDTLFO_OSC_0_60, 64);
113
114 /* Enable the power to the WDT */
115 Chip_SYSCTL_PowerUp(SYSCTL_SLPWAKE_WDTOSC_PD);
116
117 /* The WDT divides the input frequency into it by 4 */
118 wdtFreq = Chip_Clock_GetWDTOSCRate() / 4;
119
120 Board_LED_Set(0, false);
121
122 /* Initialize WWDT (also enables WWDT clock) */
123 Chip_WWDT_Init(LPC_WWDT);
124
125 /* Set watchdog feed time constant to approximately 2s
126 Set watchdog warning time to 512 ticks after feed time constant
127 Set watchdog window time to 3s */
128 Chip_WWDT_SetTimeOut(LPC_WWDT, wdtFreq * 2);
129 Chip_WWDT_SetWarning(LPC_WWDT, 512);
130 Chip_WWDT_SetWindow(LPC_WWDT, wdtFreq * 3);
131
132 /* Configure WWDT to reset on timeout */
133 Chip_WWDT_SetOption(LPC_WWDT, WWDT_WDMOD_WDRESET);
134
135 /* Clear watchdog warning and timeout interrupts */
136 Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDTOF | WWDT_WDMOD_WDINT);
137
138 /* Clear and enable watchdog interrupt */
139 NVIC_ClearPendingIRQ(WDT_IRQn);
140 NVIC_EnableIRQ(WDT_IRQn);
141
142 /* Start watchdog */
143 Chip_WWDT_Start(LPC_WWDT);
144
145 while (1) {
146 __WFI();
147 }
148 return 0;
149 }
150