UBBRH – USART Baud Rate Register High

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.

The UBRRH Register shares the same I/O location as the UCSRC Register. See the Accessing UBRRH/UCSRC Registers section which describes how to access this register.

Name:
UBBRH
Offset:
0x20
Reset:
0x00
Access:
When addressing I/O Registers as data space the offset address is 0x40
Bit76543210
URSELUBRR[3:0]
AccessR/WR/WR/WR/WR/W
Reset00000

Bit 7 – URSEL: Register Select

Register Select

This bit selects between accessing the UBRRH or the UCSRC Register. It is read as zero when reading UBRRH. The URSEL must be zero when writing the UBRRH.

Bits 3:0 – UBRR[3:0]: USART Baud Rate Register [n = 11:8]

USART Baud Rate Register [n = 11:8]

Refer to UBRRL.