small help with 8051

hi every one

i need to know what happens to the ports of the 8051 upon RESET??

i read some slides about the 8051 and sometimes they said upon reset they becomes an inputs... sometimes they said outputs

so i become confused about what happens !!!

pease help me

When in doubt consult the datasheet for the part (8051) you have.

Usually ports are defaulted as inputs. Some application specific versions do default some ports as output. When defaulted as output there also has to be a defaulted logic state of '0' or '1'.

Many times there is a small pull up resistor in processor port to make sure the input does not float which can add current drain. If no pull up then inputs should be grounded or pulled to supply.