Analog Devices ADSP-BF506F Hardware Reference Manual page 424

Programming Examples
w[p0] = r0;
/* set port f direction register to enable some GPIO as output,
remaining are input */
p0.l = lo(PORTFIO_DIR);
p0.h = hi(PORTFIO_DIR);
r0.h = 0x0000;
r0.l = 0x0FC0;
w[p0] = r0;
ssync;
/* set port f clear register */
p0.l = lo(PORTFIO_CLEAR);
p0.h = hi(PORTFIO_CLEAR);
r0.l = 0xFC0;
w[p0] = r0;
ssync;
/* set port f input enable register to enable input drivers of
some GPIOs */
p0.l = lo(PORTFIO_INEN);
p0.h = hi(PORTFIO_INEN);
r0.h = 0x0000;
r0.l = 0x003C;
w[p0] = r0;
ssync;
/* set port f polarity register */
p0.l = lo(PORTFIO_POLAR);
p0.h = hi(PORTFIO_POLAR);
r0 = 0x00000;
w[p0] = r0;
ssync;
9-42 ADSP-BF50x Blackfin Processor Hardware Reference