Alef Sin / Watchdog

Modified version of the Watchdog library with improved support for STM32

Dependents:   LightSaber iot_water_monitor_v2

Fork of Watchdog by David Smart

Watchdog.cpp@8:3c7d083f26b5, 2015-10-27 (annotated)

Committer:
salarian
Date:
Tue Oct 27 17:04:16 2015 +0000
Revision:
8:3c7d083f26b5
Parent:
7:8912bb017956
Child:
9:84f7c088c261
Limited the upper bound of the Watchdog time for STM Targets to 26.2 seconds

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WiredHome 2:2873f068f325 1 /// @file Watchdog.cpp provides the interface to the Watchdog module
WiredHome 2:2873f068f325 2 ///
WiredHome 2:2873f068f325 3 /// This provides basic Watchdog service for the mbed. You can configure
WiredHome 2:2873f068f325 4 /// various timeout intervals that meet your system needs. Additionally,
WiredHome 2:2873f068f325 5 /// it is possible to identify if the Watchdog was the cause of any
WiredHome 2:2873f068f325 6 /// system restart.
WiredHome 2:2873f068f325 7 ///
WiredHome 2:2873f068f325 8 /// Adapted from Simon's Watchdog code from http://mbed.org/forum/mbed/topic/508/
WiredHome 2:2873f068f325 9 ///
WiredHome 2:2873f068f325 10 /// @note Copyright © 2011 by Smartware Computing, all rights reserved.
WiredHome 2:2873f068f325 11 /// This software may be used to derive new software, as long as
WiredHome 2:2873f068f325 12 /// this copyright statement remains in the source file.
WiredHome 2:2873f068f325 13 /// @author David Smart
WiredHome 2:2873f068f325 14 ///
WiredHome 0:7a316f14da9c 15 #include "mbed.h"
WiredHome 0:7a316f14da9c 16 #include "Watchdog.h"
WiredHome 0:7a316f14da9c 17
WiredHome 5:2dad2a78ffbd 18 #if defined( TARGET_LPC1768 )
WiredHome 0:7a316f14da9c 19 /// Watchdog gets instantiated at the module level
WiredHome 0:7a316f14da9c 20 Watchdog::Watchdog() {
WiredHome 2:2873f068f325 21 wdreset = (LPC_WDT->WDMOD >> 2) & 1; // capture the cause of the previous reset
WiredHome 0:7a316f14da9c 22 }
WiredHome 0:7a316f14da9c 23
WiredHome 0:7a316f14da9c 24 /// Load timeout value in watchdog timer and enable
WiredHome 0:7a316f14da9c 25 void Watchdog::Configure(float s) {
WiredHome 0:7a316f14da9c 26 LPC_WDT->WDCLKSEL = 0x1; // Set CLK src to PCLK
WiredHome 0:7a316f14da9c 27 uint32_t clk = SystemCoreClock / 16; // WD has a fixed /4 prescaler, PCLK default is /4
WiredHome 2:2873f068f325 28 LPC_WDT->WDTC = (uint32_t)(s * (float)clk);
WiredHome 0:7a316f14da9c 29 LPC_WDT->WDMOD = 0x3; // Enabled and Reset
WiredHome 0:7a316f14da9c 30 Service();
WiredHome 0:7a316f14da9c 31 }
WiredHome 0:7a316f14da9c 32
WiredHome 0:7a316f14da9c 33 /// "Service", "kick" or "feed" the dog - reset the watchdog timer
WiredHome 0:7a316f14da9c 34 /// by writing this required bit pattern
WiredHome 0:7a316f14da9c 35 void Watchdog::Service() {
WiredHome 0:7a316f14da9c 36 LPC_WDT->WDFEED = 0xAA;
WiredHome 0:7a316f14da9c 37 LPC_WDT->WDFEED = 0x55;
WiredHome 0:7a316f14da9c 38 }
WiredHome 0:7a316f14da9c 39
WiredHome 0:7a316f14da9c 40 /// get the flag to indicate if the watchdog causes the reset
WiredHome 0:7a316f14da9c 41 bool Watchdog::WatchdogCausedReset() {
WiredHome 0:7a316f14da9c 42 return wdreset;
WiredHome 0:7a316f14da9c 43 }
WiredHome 5:2dad2a78ffbd 44 #elif defined( TARGET_LPC4088 )
WiredHome 5:2dad2a78ffbd 45 // from Gesotec Gesotec
WiredHome 5:2dad2a78ffbd 46 /// Watchdog gets instantiated at the module level
WiredHome 5:2dad2a78ffbd 47 Watchdog::Watchdog() {
WiredHome 5:2dad2a78ffbd 48 wdreset = (LPC_WDT->MOD >> 2) & 1; // capture the cause of the previous reset
WiredHome 5:2dad2a78ffbd 49 }
WiredHome 5:2dad2a78ffbd 50
WiredHome 5:2dad2a78ffbd 51 /// Load timeout value in watchdog timer and enable
WiredHome 5:2dad2a78ffbd 52 void Watchdog::Configure(float s) {
WiredHome 5:2dad2a78ffbd 53 //LPC_WDT->CLKSEL = 0x1; // Set CLK src to PCLK
WiredHome 5:2dad2a78ffbd 54 uint32_t clk = 500000 / 4; // WD has a fixed /4 prescaler, and a 500khz oscillator
WiredHome 5:2dad2a78ffbd 55 LPC_WDT->TC = (uint32_t)(s * (float)clk);
WiredHome 5:2dad2a78ffbd 56 LPC_WDT->MOD = 0x3; // Enabled and Reset
WiredHome 5:2dad2a78ffbd 57 Service();
WiredHome 5:2dad2a78ffbd 58 }
WiredHome 5:2dad2a78ffbd 59
WiredHome 5:2dad2a78ffbd 60 /// "Service", "kick" or "feed" the dog - reset the watchdog timer
WiredHome 5:2dad2a78ffbd 61 /// by writing this required bit pattern
WiredHome 5:2dad2a78ffbd 62 void Watchdog::Service() {
WiredHome 5:2dad2a78ffbd 63 LPC_WDT->FEED = 0xAA;
WiredHome 5:2dad2a78ffbd 64 LPC_WDT->FEED = 0x55;
WiredHome 5:2dad2a78ffbd 65 }
WiredHome 5:2dad2a78ffbd 66
WiredHome 5:2dad2a78ffbd 67 /// get the flag to indicate if the watchdog causes the reset
WiredHome 5:2dad2a78ffbd 68 bool Watchdog::WatchdogCausedReset() {
WiredHome 5:2dad2a78ffbd 69 return wdreset;
WiredHome 5:2dad2a78ffbd 70 }
WiredHome 5:2dad2a78ffbd 71 #elif defined( TARGET_STM )
WiredHome 5:2dad2a78ffbd 72 // Derived from Chau Vo
WiredHome 5:2dad2a78ffbd 73 /// Watchdog gets instantiated at the module level
WiredHome 5:2dad2a78ffbd 74 Watchdog::Watchdog() {
WiredHome 5:2dad2a78ffbd 75 wdreset = (RCC->CSR & (1<<29)) ? true : false; // read the IWDGRSTF (Independent WD, not the windows WD)
WiredHome 5:2dad2a78ffbd 76 }
WiredHome 0:7a316f14da9c 77
salarian 7:8912bb017956 78 // Compute the log2 of an integer. This is the simplest algorithm but probably is a bit slow.
salarian 7:8912bb017956 79 int log2(unsigned v)
salarian 7:8912bb017956 80 {
salarian 7:8912bb017956 81 unsigned r = 0;
salarian 7:8912bb017956 82
salarian 7:8912bb017956 83 while (v >>= 1)
salarian 7:8912bb017956 84 r++;
salarian 7:8912bb017956 85
salarian 7:8912bb017956 86 return r;
salarian 7:8912bb017956 87 }
salarian 7:8912bb017956 88
salarian 7:8912bb017956 89
WiredHome 5:2dad2a78ffbd 90 /// Load timeout value in watchdog timer and enable
salarian 7:8912bb017956 91 void Watchdog::Configure(float s) {
WiredHome 5:2dad2a78ffbd 92 // http://www.st.com/web/en/resource/technical/document/reference_manual/CD00171190.pdf
salarian 7:8912bb017956 93
salarian 7:8912bb017956 94 s = s * 40000; // The average frequency of STM32 watchdog timer is 40 kHz but it can vary between 30 and 60 kHz
salarian 7:8912bb017956 95 int scale = 1 + log2(s / 4096); // The RLR register is 12 bits and beyond that a prescaler should be used
salarian 7:8912bb017956 96 int residual = s / (1 << scale); // The value for the RLR register
salarian 7:8912bb017956 97
salarian 8:3c7d083f26b5 98 if (scale > 8) { //STM32 allows a maximum time of around 26.2 seconds for the Watchdog timer
salarian 8:3c7d083f26b5 99 scale = 8;
salarian 8:3c7d083f26b5 100 residual = 0xFFF;
salarian 8:3c7d083f26b5 101 }
salarian 8:3c7d083f26b5 102
WiredHome 5:2dad2a78ffbd 103 IWDG->KR = 0x5555; // enable write to PR, RLR
salarian 7:8912bb017956 104 IWDG->PR = scale - 2; // Prescaler has values of multiples of 4 (i.e. 2 ^2), page 486 Reference Manual
salarian 7:8912bb017956 105 IWDG->RLR = residual; // Init RLR
WiredHome 5:2dad2a78ffbd 106 IWDG->KR = 0xAAAA; // Reload the watchdog
WiredHome 5:2dad2a78ffbd 107 IWDG->KR = 0xCCCC; // Starts the WD
WiredHome 5:2dad2a78ffbd 108 }
WiredHome 0:7a316f14da9c 109
WiredHome 5:2dad2a78ffbd 110 /// "Service", "kick" or "feed" the dog - reset the watchdog timer
WiredHome 5:2dad2a78ffbd 111 void Watchdog::Service() {
WiredHome 5:2dad2a78ffbd 112 IWDG->KR = 0xAAAA;
WiredHome 5:2dad2a78ffbd 113 }
WiredHome 5:2dad2a78ffbd 114
WiredHome 5:2dad2a78ffbd 115 /// get the flag to indicate if the watchdog causes the reset
WiredHome 5:2dad2a78ffbd 116 bool Watchdog::WatchdogCausedReset() {
WiredHome 5:2dad2a78ffbd 117 if (wdreset) {
WiredHome 5:2dad2a78ffbd 118 RCC->CSR |= (1<<24); // clear reset flag
WiredHome 5:2dad2a78ffbd 119 }
WiredHome 5:2dad2a78ffbd 120 return wdreset;
WiredHome 5:2dad2a78ffbd 121 }
WiredHome 5:2dad2a78ffbd 122 #endif