watchdog timer tests
Posted: Thu Sep 22, 2016 12:59 amIn case this might be of value to someone...I did some tests of the watchdog timer and ESP.wdtDisable(), ESP.wdtEnable(0), ESP.wdtEnable(time), and ESP.wdtFeed()
Adafruit Huzzah ESP8266
Summary of results:
Test 1. If the software watchdog timer (SW wdt) is not disabled, the 1.5 s test works but the SW wdt resets during the 2.5 s test.
Test 2. if the SW wdt is disabled, the 7 s test works but the hardware watchdog timer resets during the 10 s test.
Test 3. if the SW wdt is disabled but wdtFeed() is done every 100 ms, the 20 s test works
Test 4. if the SW wdt is enabled with a 15s timeout, the 2.5 s test works, but the SW wdt resets during the 5 s test (a comment in ESP.h says the timeout is not implemented yet)
Oddly, although tests 1 and 4 fail with "soft WDT reset," cause "2" is issued, which is "reset pin," not "watchdog reset"
Adafruit Huzzah ESP8266
Summary of results:
Test 1. If the software watchdog timer (SW wdt) is not disabled, the 1.5 s test works but the SW wdt resets during the 2.5 s test.
Test 2. if the SW wdt is disabled, the 7 s test works but the hardware watchdog timer resets during the 10 s test.
Test 3. if the SW wdt is disabled but wdtFeed() is done every 100 ms, the 20 s test works
Test 4. if the SW wdt is enabled with a 15s timeout, the 2.5 s test works, but the SW wdt resets during the 5 s test (a comment in ESP.h says the timeout is not implemented yet)
Oddly, although tests 1 and 4 fail with "soft WDT reset," cause "2" is issued, which is "reset pin," not "watchdog reset"
Code: Select all
/* September 2016
this is a test of the ESP8266 watchdog timer
and
ESP.wdtDisable(), ESP.wdtEnable(0), ESP.wdtEnable(time), and ESP.wdtFeed()
which were added to ESP.h April 2015
references:
https://github.com/esp8266/Arduino/blob/master/doc/reference.md#timing-and-delays = basic ref
https://github.com/esp8266/Arduino/blob/master/cores/esp8266/Esp.h = note line 89 comment that timeout value is not implemented
http://bbs.espressif.com/viewtopic.php?f=7&t=203 = says watchdog timeout is about 1 s...but see next reference!
http://bbs.espressif.com/viewtopic.php?t=836 = implies software WDT resets after 3.2 s, and hardware WDT resets after 6 s
in the example, not sure why it is necessary to feed the soft WDT after it is stopped (maybe that keeps the HW WDT from timing out?)
http://internetofhomethings.com/homethings/?p=396 = suggests that timeout is about 5 s
https://github.com/esp8266/Arduino/issues/34 = May 5 test not valid since delay(10000) kicks WDT?
https://github.com/esp8266/Arduino/issues/1532 = note Jan 29 comment re SPIFFS"
igrr said "The only concern is that there are a few APIs in the core and libraries which are blocking.
I.e. you have blocking reads and writes with WiFi client and SPIFFS.
These may take unpredictable amount of time,
without giving the sketch a chance to feed the watchdog."
https://github.com/esp8266/Arduino/blob/master/doc/boards.md#boot-messages-and-modes
rst cause:2, boot mode:(3,6)
cause:
0 unknown
1 normal boot
2 reset pin
3 software reset
4 watchdog reset
boot mode:(x,y)
"the first value respects the pin setup of the Pins 0, 2 and 15" <- is not standard English
DAE's note: although the above is not entirely clear, the "first" value (i.e., x)
appears to be the boot mode (based on GPIO pin states):
1=UART bootloader (if 15=0v, 0=0v, 2=3.3v)
2=boot sketch i.e. SPI flash (if 15=0v, 0=3.3v, 2=3.3v)
3=SDIO mode not used for Arduino (15=3.3v, others = don't care)
number = ((GPIO15 << 2) | (GPIO0 << 1) | GPIO2), where 0 v = 0, and 3.3v = 1
Number GPIO15 GPIO0 GPIO2 Mode
0 0V 0V 0V Not valid
1 0V 0V 3.3V Uart
2 0V 3.3V 0V Not valid
3 0V 3.3V 3.3V Flash
4 3.3V 0V 0V SDIO
5 3.3V 0V 3.3V SDIO
6 3.3V 3.3V 0V SDIO
7 3.3V 3.3V 3.3V SDIO
DAE's note: "number" appears to be the "second" value (i.e., y)
*/
#include <ESP.h>;
void setup(){
Serial.begin(115200);
Serial.println("wdt");
test3(500);
test3(1000);
test3(1500);
test3(2500); // test1 fails here with "soft WDT reset" cause:2, boot mode:(1,6) <- cause 2 = reset pin (??)
test3(5000); // test4 fails here with "soft WDT reset" cause:2, boot mode:(1,6) <- cause 2 = reset pin (??)
test3(7000);
test3(10000); // test2 fails here with "wdt reset" cause:4, boot mode:(1,6)
test3(20000);
// test3(20000) executes without reset
}
void loop() {
}
// test1();
// should trigger SW WDT reset
// if the while loop duration is long enough
void test1(unsigned long testDuration){
Serial.print("test1 "); Serial.print(testDuration); Serial.print(" ");
unsigned long prevTime=millis();
while (millis()-prevTime<testDuration) {}
Serial.println(" end");
}
// test2();
// since SW WDT is disabled
// should NOT trigger SW WDT reset
// provided that duration is short enough
// but if duration is too long, HW WDT will reset
void test2(unsigned long testDuration){
Serial.print("test2 "); Serial.print(testDuration); Serial.print(" ");
ESP.wdtDisable();
unsigned long prevTime=millis();
while (millis()-prevTime<testDuration) {}
ESP.wdtEnable(0);
Serial.println(" end");
}
// test3();
// same as test2(), but test to see
// if feeding the WDT prevents
// the HW WDT from timing out (as implied by above ref)
void test3(unsigned long testDuration){
Serial.print("test3 "); Serial.print(testDuration); Serial.print(" ");
ESP.wdtDisable();
unsigned long prevTime=millis();
unsigned long prevTime2=prevTime;
while (millis()-prevTime<testDuration) {
if (millis()-prevTime2>100){ // feed every 100 ms
prevTime2=millis();
ESP.wdtFeed();
}
}
ESP.wdtEnable(0);
Serial.println(" end");
}
// test4();
// since timeout value not implemented (per Github comment)
// if duration is long enough,
// should trigger WDT SW reset
void test4(unsigned long testDuration){
Serial.print("test4 "); Serial.print(testDuration); Serial.print(" ");
ESP.wdtDisable();
ESP.wdtEnable(15000);
unsigned long prevTime=millis();
while (millis()-prevTime<testDuration) {}
Serial.println(" end");
}