Hi there,
Using the AT90USB647 PINF[1] as a digital input (without pull up), I try to read a manchester encoded data that is coming from the output of an LM358 opamp. The opamp is used as a non-inverted amplifier:
5V === |\ | | \| ----------------------|+ \ | \ | /----------- PINF[1] ------|- / | | | /| | | |/ | | | === | | | |------100K------ | 10 Ohm | === -
The oscilloscope is connected to the output of the opamp and when using this function I can see the manchester encoded data.
while(1){ __watchdog_reset(); }
But when I pole the PINF[1] like this:
while(1){ if (PINF_Bit1){ .... } else{ .... } __watchdog_reset(); }
then something mysterious is happened. The manchester data is changing it's level randomly and in higher frequency than the original one. It seems like when I test the PINF[1] pin something causes the data voltage level, to be change randomly.
Do you have any idea?
Thank you.