Thatcher Chamberlin / Mbed 2 deprecated WatchDogTest

The common example for running a watchdog timer on mbed processors doesn't work for the LPC1114, a common and easily-breadboardable ARM chip. My program provides a watchdog class that works on the LPC1114 but which is also similar to the common example found in https://mbed.org/forum/mbed/topic/508/

Dependencies:   mbed

main.cpp@0:1c1e04c41063, 2014-08-10 (annotated)

Committer:
ThatcherC
Date:
Sun Aug 10 02:58:11 2014 +0000
Revision:
0:1c1e04c41063
First commit of Watchdog implementation for LPC1114 on the mbed platform.; ; Seems to work.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ThatcherC 0:1c1e04c41063 1 #include "mbed.h"
ThatcherC 0:1c1e04c41063 2
ThatcherC 0:1c1e04c41063 3 /*
ThatcherC 0:1c1e04c41063 4 Main code copied from: http://mbed.org/cookbook/WatchDog-Timer
ThatcherC 0:1c1e04c41063 5 Modified for use with LPC1114 with source code found here:
ThatcherC 0:1c1e04c41063 6 https://github.com/mbedmicro/mbed/blob/master/libraries/mbed/targets/cmsis/TARGET_NXP/TARGET_LPC11XX_11CXX/LPC11xx.h
ThatcherC 0:1c1e04c41063 7 With some inspiration from:
ThatcherC 0:1c1e04c41063 8 https://github.com/Mrjohns42/RSL/blob/master/LPC1114/nRF24L01/wdt.c
ThatcherC 0:1c1e04c41063 9 */
ThatcherC 0:1c1e04c41063 10
ThatcherC 0:1c1e04c41063 11 // LEDs used to indicate code activity and reset source
ThatcherC 0:1c1e04c41063 12 DigitalOut led1(dp1);
ThatcherC 0:1c1e04c41063 13 DigitalOut led2(dp4);
ThatcherC 0:1c1e04c41063 14
ThatcherC 0:1c1e04c41063 15 // Simon's Watchdog code from
ThatcherC 0:1c1e04c41063 16 // http://mbed.org/forum/mbed/topic/508/
ThatcherC 0:1c1e04c41063 17 class Watchdog {
ThatcherC 0:1c1e04c41063 18 public:
ThatcherC 0:1c1e04c41063 19 // Load timeout value in watchdog timer and enable
ThatcherC 0:1c1e04c41063 20 void kick(float s) {
ThatcherC 0:1c1e04c41063 21 LPC_SYSCON->SYSAHBCLKCTRL = LPC_SYSCON->SYSAHBCLKCTRL|(1<<15);
ThatcherC 0:1c1e04c41063 22 LPC_SYSCON->WDTCLKSEL = 0x1; // Set CLK src to Main Clock
ThatcherC 0:1c1e04c41063 23 LPC_SYSCON->WDTCLKUEN = 0x01; /* Update clock */
ThatcherC 0:1c1e04c41063 24 LPC_SYSCON->WDTCLKUEN = 0x00; /* Toggle update register once */
ThatcherC 0:1c1e04c41063 25 LPC_SYSCON->WDTCLKUEN = 0x01;
ThatcherC 0:1c1e04c41063 26 LPC_SYSCON->WDTCLKDIV = 0x10;
ThatcherC 0:1c1e04c41063 27 uint32_t clk = SystemCoreClock/16; // WD has a fixed /4 prescaler, PCLK default is /4
ThatcherC 0:1c1e04c41063 28 LPC_WDT->TC = s * (float)clk;
ThatcherC 0:1c1e04c41063 29 LPC_WDT->MOD = 0x3; // Enabled and Reset
ThatcherC 0:1c1e04c41063 30 kick();
ThatcherC 0:1c1e04c41063 31 }
ThatcherC 0:1c1e04c41063 32 // "kick" or "feed" the dog - reset the watchdog timer
ThatcherC 0:1c1e04c41063 33 // by writing this required bit pattern
ThatcherC 0:1c1e04c41063 34 void kick() {
ThatcherC 0:1c1e04c41063 35 LPC_WDT->FEED = 0xAA;
ThatcherC 0:1c1e04c41063 36 LPC_WDT->FEED = 0x55;
ThatcherC 0:1c1e04c41063 37 }
ThatcherC 0:1c1e04c41063 38 };
ThatcherC 0:1c1e04c41063 39
ThatcherC 0:1c1e04c41063 40 // Setup the watchdog timer
ThatcherC 0:1c1e04c41063 41 Watchdog wdt;
ThatcherC 0:1c1e04c41063 42
ThatcherC 0:1c1e04c41063 43 int main() {
ThatcherC 0:1c1e04c41063 44 int count = 0;
ThatcherC 0:1c1e04c41063 45 // On reset, indicate a watchdog reset or a pushbutton reset on LED 4 or 3
ThatcherC 0:1c1e04c41063 46 if ((LPC_WDT->MOD >> 2) & 1)
ThatcherC 0:1c1e04c41063 47 led1 = 1; else led1 = 0;
ThatcherC 0:1c1e04c41063 48
ThatcherC 0:1c1e04c41063 49 // setup a 10 second timeout on watchdog timer hardware
ThatcherC 0:1c1e04c41063 50 // needs to be longer than worst case main loop exection time
ThatcherC 0:1c1e04c41063 51 wdt.kick(10.0);
ThatcherC 0:1c1e04c41063 52
ThatcherC 0:1c1e04c41063 53 // Main program loop - resets watchdog once each loop iteration
ThatcherC 0:1c1e04c41063 54 // Would typically have a lot of code in loop with many calls
ThatcherC 0:1c1e04c41063 55 while (1) {
ThatcherC 0:1c1e04c41063 56 wait(.1);
ThatcherC 0:1c1e04c41063 57 led2 = 1;
ThatcherC 0:1c1e04c41063 58 wait(.1);
ThatcherC 0:1c1e04c41063 59 // Simulate a fault lock up with an infinite while loop, but only after 25 loop iterations
ThatcherC 0:1c1e04c41063 60 if (count == 25) while (1) {};
ThatcherC 0:1c1e04c41063 61
ThatcherC 0:1c1e04c41063 62 // LED 2 will stay on during the fault
ThatcherC 0:1c1e04c41063 63 led2 = 0;
ThatcherC 0:1c1e04c41063 64 count ++;
ThatcherC 0:1c1e04c41063 65 // End of main loop so "kick" to reset watchdog timer and avoid a reset
ThatcherC 0:1c1e04c41063 66 wdt.kick();
ThatcherC 0:1c1e04c41063 67 }
ThatcherC 0:1c1e04c41063 68 }