The Codi Corporation and its principal subsidiary, Codi Semiconductor Inc. of Linden, N.J., announced they had filed petitions under Chapter 11 of the Federal bankruptcy law.

    Harold B. Rosenberg, president and chief executive officer of the Codi Corporation, said that the company was continuing to operate as a debtor-in-possession. Current management, which was brought in three years ago to try to turn around the company, ''just now got Codi operating at a break-even point,'' by introducing new semiconductors, selling two subsidiaries and laying off 100 employees, Mr. Rosenberg said. But the company still has $2 million in debts. In its latest reporting period, the nine months ended Sept. 30, 1981, the company posted a loss of $666,000.