This is the area to clarify hardware specification if there's anything unclear from the datasheet. If the specification is software related, please ask in the related software section.

how to write bare-metal device drivers

I'm porting a proprietary real-time OS onto UP board and need to develop the bare-metal device drivers, such as  GPIO, I2C and UART peripherals on the 40-pin header.

    Is there any examples and/or documents to help me get started ? Thanks in advanced.