Hi all,
Bit of a strange problem, wondered if anyone else had experienced it.
Not wanting to waste time, again, trying to do my own code to read the DS18B20 I opted to use the free code from this project Digital Clock/Date/Thermometer with PIC16F628/PIC16F84 and DS18S20/DS18B20
I simply converted the code to run on the 18F4520 at 4 meg and all seemed to work well.
I could icsp the chip and run or even use PK2 debugger without any errors.
However if I switch off and repower the circiut the first temp returned is 85c instead of room temp at 20c.
I have done various tests using 85c counter traps and it only occurrs at power up.
I can delay for 5 seconds before reading the sensor but it still returns 85c that one time.
If I force the program to Reset by the menu left open timeout routine it still does not sense 85c so I think that excludes any problem in the early part of my main program code.
While the error is easily overcome by software it would be good to know the cause of the problem in case there is a more underlying fault.
thanks
Bit of a strange problem, wondered if anyone else had experienced it.
Not wanting to waste time, again, trying to do my own code to read the DS18B20 I opted to use the free code from this project Digital Clock/Date/Thermometer with PIC16F628/PIC16F84 and DS18S20/DS18B20
I simply converted the code to run on the 18F4520 at 4 meg and all seemed to work well.
I could icsp the chip and run or even use PK2 debugger without any errors.
However if I switch off and repower the circiut the first temp returned is 85c instead of room temp at 20c.
I have done various tests using 85c counter traps and it only occurrs at power up.
I can delay for 5 seconds before reading the sensor but it still returns 85c that one time.
If I force the program to Reset by the menu left open timeout routine it still does not sense 85c so I think that excludes any problem in the early part of my main program code.
While the error is easily overcome by software it would be good to know the cause of the problem in case there is a more underlying fault.
thanks