AN 100: In-System Programmability Guidelines

ID 683546
Date 9/22/2014
Document Table of Contents

1.1.3. Interrupting In-System Programming

Altera does not recommend interrupting the programming process because partially programmed devices operate unpredictably. Partially programmed devices also cause signal conflicts, which can lead to permanent device damage and can affect the proper operation of other devices on the board.

MAX II, MAX V and MAX 10 devices have an ISP_DONE bit that you can only set at the end of a successful program sequence. The I/O pins can only drive out if this bit is set. This prevents a partially programmed device from driving out and operating unpredictably.