31.5.15 I/O Lines Programming Example
The following table provides an example of programming I/O lines to obtain these configuration:
- 4-bit output port on I/O lines 0 to 3 (must be written in a single write operation), open drain, with pull-up resistor
- Four output signals on I/O lines 4 to 7 (for example, to drive LEDs) driven high and low, no pull-up resistor, no pull-down resistor
- Four input signals on I/O lines 8 to 11 (for example, to read push-button states), with pull-up resistors, glitch filters, and input change interrupts
- Four input signals on I/O line 12 to 15 to read an external device status (polled, thus no input change interrupt), no pull-up resistor, no glitch filter
- I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor
- I/O lines 20 to 23 assigned to peripheral B functions with pull-down resistor
- I/O lines 24 to 27 assigned to peripheral C with input change interrupt, no pull-up resistor and no pull-down resistor
- I/O lines 28 to 31 assigned to peripheral D, no pull-up resistor
and no pull-down resistor
Table 31-3. Programming Example Register Value to be Written PIO_PER 0x0000_FFFF PIO_PDR 0xFFFF_0000 PIO_OER 0x0000_00FF PIO_ODR 0xFFFF_FF00 PIO_IFER 0x0000_0F00 PIO_IFDR 0xFFFF_F0FF PIO_SODR 0x0000_0000 PIO_CODR 0x0FFF_FFFF PIO_IER 0x0F00_0F00 PIO_IDR 0xF0FF_F0FF PIO_MDER 0x0000_000F PIO_MDDR 0xFFFF_FFF0 PIO_PUDR 0xFFF0_00F0 PIO_PUER 0x000F_FF0F PIO_PPDDR 0xFF0F_FFFF PIO_PPDER 0x00F0_0000 PIO_ABCDSR0 0xF0F0_0000 PIO_ABCDSR1 0xFF00_0000 PIO_OWER 0x0000_000F PIO_OWDR 0x0FFF_FFF0