18.4.1 SFIOR – Special Function IO Register
When using the I/O specific commands IN and OUT, the I/O addresses 0x00 - 0x3F must be used. When addressing I/O Registers as data space using LD and ST instructions, 0x20 must be added to these offset addresses.
| Name: | SFIOR |
| Offset: | 0x30 |
| Reset: | 0 |
| Property: | When addressing I/O Registers as data space the offset address is 0x50 |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| PUD | |||||||||
| Access | R/W | ||||||||
| Reset | 0 |
Bit 2 – PUD Pull-up Disable
When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn and PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01). See Configuring the Pin for more details about this feature.