NuMicro® NUC029LEE/NUC029SEE32-bit Arm® Cortex® -M0 MicrocontrollerAug, 2018 Page 176 of 497 Rev 1.00NUMICRO® NUC029LEE/NUC029SEE TECHNICAL REFERENCE MANUAL6.6 General Purpose I/O (GPIO)6.6.1 OverviewThe NuMicro® NUC029LEE/NUC029SEE has up to 45 General Purpose I/O pins to be sharedwith other function pins depending on the chip configuration. These 45 pins are arranged in 5ports named as GPIOA, GPIOB, GPIOC, GPIOE and GPIOF. The GPIOA/B/C/E port has themaximum of 15 pins and GPIOF port has the maximum of 2 pins. Each of the 45 pins isindependent and has the corresponding register bits to control the pin mode function and data.The I/O type of each of I/O pins can be configured by software individually as input, output, open-drain or Quasi-bidirectional mode. After reset, the I/O mode of all pins are depending onConfig0[10] setting. In Quasi-bidirectional mode, I/O pin has a very weak individual pull-upresistor which is about 110~300 K for VDD is from 5.0 V to 2.5 V.6.6.2 Features Four I/O modes:- Quasi-bidirectional- Push-Pull output- Open-Drain output- Input only with high impendence TTL/Schmitt trigger input selectable by GPx_TYPE[15:0] in GPx_MFP[31:16] I/O pin configured as interrupt source with edge/level setting Configurable default I/O mode of all pins after reset by Config0[10] setting- If Config[10] is 0, all GPIO pins in input tri-state mode after chip reset- If Config[10] is 1, all GPIO pins in Quasi-bidirectional mode after chip reset I/O pin internal pull-up resistor enabled only in Quasi-bidirectional I/O mode Enabling the pin interrupt function will also enable the pin wake-up function.
