I'm designing a system with K64 MCU
My question regarding all GPIO's state on power-up :
1. The GPIO's state on boot is output or input ? if so, is it PU/PD/HiZ ?
2. What doe's it mean that the default function of a GPIOs is "DISABLED" ?
Looking at the reference manual - http://cache.freescale.com/files/microcontrollers/doc/ref_manual/K64P144M120SF5RM.pdf
Page 244, chapter 10.2.2 Port control and interrupt summary
"Pull enable at reset - Disabled" - so i can understand from that that the GPIO is defined as Input Hi-Z ?
Please clarify this issue for me
Thanks & Regards
Hello Eduard Razumovsky:
Mark's response is completely correct. You should look at the Default column in the pinout table.
DISABLED indicates no function after reset, so that is High-Impedance.
Pins with an analog MUX option will be connected by default after reset to their corresponding analog module.
Okay, but what about this case on my MK02Z?
On power-up PTB4 seems to follow the VCC ramp and after PE initialization this is set as a digital output with zero value.
No pins are GPIOs outputs after reset.
If their pull-up is disabled at reset it means that there is no pull-up or pull-down connected. [Only the pins that default to JTAg use have pull-ups or downs eabled out of reset].
Some pins default to peripheral functions (see 10.3.1) and not GPIO.
If disabled out of reset, it means that there is no connected default function - the pin is not GPIO input without first setting the GPIO Mux function (Alt 1).
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