AnsweredAssumed Answered

Coldfire processor lock up

Question asked by NAGA AMAM on May 27, 2015
Latest reply on Jun 10, 2015 by NAGA AMAM


Our system is based on Coldfire Micro MCF52235, and the Hardware

design is very similar to EVAL board. In our current design the 25MHZ clock input comes from
EMI Reduction clock Generator, and that IC is getting obsolete and so we
are testing the performance with the new EMI reduction clock Generator IC
(P2781A from ON SEMI), and with this new IC we are seeing good
25MHZ signal generated but the controller is not booting up most of the
times, if we recycle the power several times, occasionally it is booting OK.
Once It boots up it continuous to work good.

When the Controller is in lockup condition, I have tried to generate RESET
to controller (by shorting RSTI pin to ground, as we use simple RC network
to generate RESET to micro) , but there is no use, the Micro is not
responding and continue to stay in that lock up condition.

I am not really What is controller doing during that lockup condition and
why it is not responding to RESET, Do you have any ideas how to overcome this situation?
Please note that the RCON pin has pullup resistor of value 4.7K.