Configuring for General Purpose

Basically you can configure a GPIO port either for input or for output, the topic provides examples on the configuration.

Configuring for Output

The following code block provides an example of configuring GPIO11 as an output port.

port = 11;
n = port >> 2;
shift = ((port & 0x3) << 3);
//direction = output
modl(regs->doen+n, GPIO_DOEN_MASK<<shift, 0<<shift);
//pull up
modl(regs->dout+n, GPIO_DOUT_MASK<<shift, 1<<shift);
//pull down
modl(regs->dout+n, GPIO_DOUT_MASK<<shift, 0<<shift);

Configuring for Input

The following code block provides an example of configuring GPIO12 as an input port.

port = 12;
n = port >> 2;
shift = ((port & 0x3) << 3);
// direction = input
modl(regs->doen+n, GPIO_DOEN_MASK<<shift, 1<<shift);

// connect 3.3V to pull up, or GND to pull down.

value = (regs->din[port>>5] >> (port & 0x1F)) & 0x1;