I am trying and failing to implement the watchdog timer on an Arduino Pro Mini 3.3V 8 MHZ. I've read lots of posts. It's my understanding that I need to implement a different bootloader to make it work. I've tried everything recommended but still fail. In particular,
Followed the procedures in https://www.arduino.cc/en/Tutorial/ArduinoISP.
Verified conversion of 5V logic on Arduino Uno (programming option Arduino as ISP) on pins 10, 11, 12, 13 to corresponding pins RST, 11, 12, 13 respectively on Pro Mini.
Downloaded ArdinonISP from IDE to Arduino Uno,
Put 20 microcFarad capacitor across Uno RST to ground.
Specified Pro Mini at 3.3V/8MHz in IDE for bootloader.
Specified Arduino as ISP in Programmer in IDE for bootloader.
Ran bootloader for several different bit rate settings in Arduino ISP.
Every time a get an error message (Attached) that includes the following lines:
"avrdude: Device signature = 0xffffff (probably .reduced_core_tiny)
"avrdude: Yikes! Invalid device signature.
" Double check connections and try again, or use -F to override
" this check.
"
"
"avrdude done. Thank you."
My reading indicates that this message means that the Arduino UNO is not recognizing the Pro Mini. I've repeatedly checked on successive days the wiring and logic level conversion, as recommended when this message is seen. I've also checked the capacitor to verify that I do not have a short to ground. All wiring seems to be as directed and intended, logic conversions are as intended, and capacitor is fine.
Two issues, then. First, if anyone knows of a workaround for enabling the watchdog timer on the 3.3/8MHz Pro Mini that doesn't require a PhD in computer science, I'd love to hear it.
Second, if anyone has successfully reprogrammed the bootloader on a 3.3V/8MHz Pro Mini and implemented the watchdog timer, please tell me what I'm doing wrong.
I am aware that I'm not the first to struggle with this, but have spent a lot of time to no avail trying to fix the problem.
Thanks.
