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What is the default state of General Purpose Input/Output (GPIO) after reset?

Posted: 24 Mar 2017, 15:08
by Henry
The default state of GPIO after reset may vary depending on the product series.
The state of GPIO for M051 BN and NUC100 Series is in Quasi-bidirectional mode with weakly pull-high resistor (110 kΩ~300 kΩ), and the state of GPIO for Mini51 and Nano100 Series is in Input mode.
However, the state of GPIO for M051 DN/DE and NUC200 Series depends on the setting of CIOINI (Config0[10]).
If CIOINI is set to 1, all pins will be in Quasi-bidirectional mode after reset.
If CIOINI is cleared to 0, all pins will be Input mode after reset.