EAMCET and BITSAT are totally different from each other. Even syllabus is somewhat different from each other.

EAMCET is a state level exam and it's level is easier then BITSAT exam.

BITSAT is more logical test and questions in EAMCET is straight forward.

For EAMCET you can prepare from your text book of 12th class and for BITSAT you need to refer NCERT books.

Good Luck!!