I have small display and it is controlled by AT89C2051, Now I have to change firmware and would like use AT-Tiny4313 (it is pin compatible with 89C2051 (except RESET)). When I wrote SW and connect Tiny4313 to display after approx 20sec broke PIN D5. I am using it like INPUT with internal PULL-UP. It is broken that, it is not working like input and it is permanently in LOW, no chance PULL-UP it externally - I have tried it. When I try change status to OUTPUT and change port value LOW-HIGH-LOW-HIGH-... it is working. When I connect signal from D5 to another pin like D6 or D4 - it is working without problems.
- Note: I thing, there is not problem with my connection because another ports has the same external connections, but only D5 has this problems. I have tried connect 2 TINYs4313. And the both has the same fault.
My question: D5 is has different electrical characteristics?
Has anybody the same exprience?