ATTINY817-MFR. datasheet(111/492 Pages) MICROCHIP

111 / 492 page

16.3.2

Operation

16.3.2.1 Basic Functions

Each I/O pin Pxn can be controlled by the registers in PORT x. Each pin group x has its own set of PORT

registers, the base address of the register set for pin n is at the byte address

PORT+0x10+��.The

index within that register set is n.

To use pin number n as an output only, write bit n of the PORT.DIR register to '1'. This can also be done

by writing bit n in the PORT.DIRSET register to '1' - this will avoid disturbing the configuration of other

pins in that group. The nth bit in the PORT.OUT register must be written to the desired output value.

Similarly, writing a PORT.OUTSET bit to '1' will set the corresponding bit in the PORT.OUT register to '1'.

Writing a bit in PORT.OUTCLR to '1' will clear that bit in PORT.OUT to zero. Writing a bit in

PORT.OUTTGL or PORT.IN to '1' will toggle that bit in PORT.OUT.

To use pin n as an input, bit n in the PORT.DIR register must be written to '0' to disable the output driver.

This can also be done by writing bit n in the PORT.DIRCLR register to '1' - this will avoid disturbing the

configuration of other pins in that group. The input value can be read from bit n in register PORT.IN as

long as the ISC bit is not set to INPUT_DISABLE.

Writing a bit to '1' in PORT.DIRTGL will toggle that bit in PORT.DIR, and toggle the direction of the

corresponding pin.

16.3.2.2 Virtual Ports

The Virtual Port registers map the most frequently used regular Port registers into the bit-accessible I/O

space. Writing to the Virtual Port registers has the same effect as writing to the regular registers, but

allows for memory-specific instructions, such as bit-manipulation instructions, which are not valid for the

extended I/O memory space where the regular Port registers reside.

Table 16-2. Virtual Port Mapping

Regular Port Register

Mapped to Virtual Port Register

PORT.DIR

VPORT.DIR

PORT.OUT

VPORT.OUT

PORT.IN

VPORT.IN

PORT.INTFLAG

VPORT.INTFLAG

ATTINY817-MFR. Datasheet(PDF) 111 Page - Microchip Technology