Carlos Pineiro

my microcontroller is not booting

Discussion created by Carlos Pineiro on Mar 18, 2010
Latest reply on Mar 19, 2010 by Daniel Lundin

Hi All,

 

I have an strange problem with my last design. I am using a KA4 in a simple standby circuit. The KA4 has an indepent voltage regulator and reset of the rest of the circuit, and is used to manage the power and the resets of the other chips at the board.

 

The problem is that if the rest of the board is powered, the KA4 is working correctly, but If I place the transistors to cut the power in the rest of the board, the KA4 is not booting (the outputs are in a undefined state, ~1.2V). I also cannot acceed with the programmer. If I remove the transistors and place 0R resistors, I can program the KA4 again, and it works perfectly.

 

I´ve checked the reset signal with the oscilloscope, and it´s perfect. Exactly the same in both cases (power and reset are absolutely independent of the ret of the circuit). The power is also clean and stable in both cases.

 

Any idea?

Outcomes