Exactly. These cheap external chips have a rc time constant and are pulsed by a GPIO . Output can generate an Interrupt back to Bbb to save important data.
Sent from Yahoo Mail on Android On Mon, May 16, 2016 at 3:50 AM, Micka<[email protected]> wrote: You dont need an external microcontroller.... Some watchdog from Texas do a good job like the uccx946. Le lun. 16 mai 2016 09:01, arsi <[email protected]> a écrit : Hi, I use this: PIC 10F200 source code: /* File: main.c Author: arsi Created on May 22, 2015, 10:32 AM */ #include <xc.h> #include <stdbool.h> #include <stdint.h> #define _XTAL_FREQ 4000000 #pragma config WDTE = ON // Watchdog Timer (WDT enabled) #pragma config CP = OFF // Code Protect (Code protection off) #pragma config MCLRE = OFF // Master Clear Enable (GP3/MCLR pin fuction is digital I/O, MCLR internally tied to VDD) void delay1() { __delay_ms(1000); } bool flag = false; int counter = 0; void main(void) { #asm CLRWDT CLRF TMR0 CLRWDT MOVLW 0b00001111 OPTION #endasm CLRWDT(); TRIS = 0b1110; CLRWDT(); GP0 = 0; __delay_ms(500); CLRWDT(); TRIS = 0b1111; CLRWDT(); //pause for BBB boot up for (int i = 0; i < 120; i++) { delay1(); CLRWDT(); } counter = 0; while (true) { delay1(); if (counter < 120) { CLRWDT(); } if (flag != GP1) { counter = 0; flag = GP1; } else { counter++; } } } ******************************************************************************************* wd script on BBB: #!/bin/bash sleep 10 echo 60 > /sys/class/gpio/export echo "out" > /sys/class/gpio/gpio60/direction while : do echo "0" > /sys/class/gpio/gpio60/value sleep 1 echo "1" > /sys/class/gpio/gpio60/value sleep 1 done *********************************************************************************************** Arsi From: Kb2pnm Sent: Saturday, March 22, 2014 6:08PM To: Beagleboard Subject: [beagleboard] Hardware watchdog for BBB HI, I have been working for a wile on safe power supply for BBB with backup power provided by supercapacitors. In case of power failure there is just enough time to safely and nicely shut down BBB. For some reason BBB does not always wake up fully. I need hardware dogwatch. Did anybody design such a thing? I was able to find some design for ardunio: http://www.playwitharduino.com/?p=291. Anybody has any experience with hardware dogwatch for BBB?? Thanks in advance Robert -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/57397009.2000005%40chello.sk. For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAF%2BMRtmfNSrCXk-egMpz-gGqzjt%3D8qRgsrzv2FbrQUqrLAw0Lw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/587089779.3315783.1463416888133.JavaMail.yahoo%40mail.yahoo.com. For more options, visit https://groups.google.com/d/optout.
