Good day.In the finished product, which has been produced for a long time, they found a problem when supplying power to cyclone ep1с3т100с8n at the outputs a short high level of 3.3 V, even before the configuration was started. Is this normal and something can be done about it? Thank you.
Before user configuration becomes effective, all IOs are pulled up by a weak pull-up resistor, a well documented behavior of all Altera FPGAs.The best solution is to chose active low level for critical signals, e.g. when turning on external devices. The next best is to add external pull-down resistors to these pins that override the weak pull-up.