P2 (GPIO0) becomes HIGH during startup

MediaTek-Labs / Arduino-Add-On-for-LinkIt-SDK

Arduino board support package for LinkIt 7697

https://docs.labs.mediatek.com/resource/linkit7697-arduino/en

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P2 (GPIO0) becomes HIGH during startup #31

Closed pablosun closed 7 years ago

pablosun commented 7 years ago

D2/P2 (GPIO0) becomes OUTPUT HIGH during board startup, before sketch runs. This may cause some issues when attaching D2 to some outpu devices such as switch or LED.

pablosun commented 7 years ago

This is caused by bootloader's default pin assigned (D2/P2 is assigned as UART0_RTS, which is default HIGH). We need to adjust the default pinmux to make D2 a GPIO pin by default.

The default pinmux are determined by the bootloader. Therefore, the user needs to manually update the bootloader to solve this problem.

pablosun commented 7 years ago

This problem should be fixed after updating the new bootloader. The user can choose "Program Bootloader" action from Arduino IDE menu to do so.