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  MC9S12XEP100 Reset and Configuration mode pin sharing

Question asked by Daniel Flor on Jun 1, 2020
Latest reply on Jun 2, 2020 by lama

Hello, 

 

I'm migrating from the MC9S12DP512 microcontroller to the MC9S12XEP100 microcontroller. And I have the following questions:

 

1)  For the MC9S12DP512, the MC34064D05 CI was used as a RESET circuit, which is a circuit for low voltage detection. However, in the MC9S12XEP100 microcontroller, there is an LVR (Low-voltage reset) module, so, I wonder if the LVR module would eliminate the need to use an external low voltage detector circuit with the MC34064D05 IC.

 

2)  RE and MODA are shared, pin 50 of the microcontroller MC9S12XEP100 . MODA is a microcontroller configuration pin and is used only during the reset phase, RE is required to access external memory. I will need both features and I believe that the pull-down resistor at the MODA pin will not cause any problems during use of RE, but I'm not sure. I mean, can I change the pin 50 to be used as RE during normal operation after the reset ?

 

With my best regards,

Daniel.

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