92
6174B–ATARM–07-Nov-05
AT91FR40162S Preliminary
14.4
Interrupts
Each parallel I/O can be programmed to generate an interrupt when a level change occurs. This
is controlled by the PIO_IER (Interrupt Enable) and PIO_IDR (Interrupt Disable) registers which
enable/disable the I/O interrupt by setting/clearing the corresponding bit in the PIO_IMR. When
a change in level occurs, the corresponding bit in the PIO_ISR (Interrupt Status) is set whether
the pin is used as a PIO or a peripheral and whether it is defined as input or output. If the corre-
sponding interrupt in PIO_IMR (Interrupt Mask) is enabled, the PIO interrupt is asserted.
When PIO_ISR is read, the register is automatically cleared.
14.5
User Interface
Each individual I/O is associated with a bit position in the Parallel I/O user interface registers.
Each of these registers are 32 bits wide. If a parallel I/O line is not defined, writing to the corre-
sponding bits has no effect. Undefined bits read zero.