EMIOS pins are generating output voltage while loading code

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EMIOS pins are generating output voltage while loading code

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bulent_kupeli
Contributor II

Hi all, I see a problem while working MPC5644.Actually, I dont know that this is a problem or not. My problem is that EMIOS pins are generating output volatge while I load code in MPC5644 or I turn on or off the power of MPC5644A. The EMIOS pins keep output voltage during 70 ms while turning on / off power and like this, the EMIOS pins keep output voltage during loading code in MPC5644A. After I load code, everything is okay. I made 0 to initial values of this pins but I see output voltage while loading code and powering on / off. Can you help me? Why do I see this stiation?

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davidtosenovjan
NXP TechSupport
NXP TechSupport

Hi,

Firstly I had power-up sequence on my mind, but only fast pads may be driven high by this cause. Slow/Medium pads may only be driven low (see Table 20 in the device DS).

 

However as you can in the Table 1, some eMIOS pins has default state during and after reset with internal pull-ups enabled (other pull-downs or WKPCFG dependent).

 

If it is any issue or not is application dependent, if it could, user would have to use stronger external pull-ups (typically 4k7 or 1k) to overweight default internal weak pull resistor configuration or to use different eMIOS channels.