Datasheet

24.12.5 USART Baud Rate 0 Register Low and High byte

Name: UBRR0L and UBRR0H

Offset: 0xC4

Reset: 0x00

Property: -

The UBRR0L and UBRR0H register pair represents the 16-bit value, UBRR0. The low byte [7:0] (suffix L)

is accessible at the original offset. The high byte [15:8] (suffix H) can be accessed at offset + 0x01. For

more details on reading and writing 16-bit registers, refer to Accessing 16-bit Timer/Counter Registers.

Bit 15 14 13 12 11 10 9 8

UBRR0[11:8]

Access

R/W R/W R/W R/W

Reset 0 0 0 0

Bit 7 6 5 4 3 2 1 0

UBRR0[7:0]

Access

R/W R/W R/W R/W R/W R/W R/W R/W

Reset 0 0 0 0 0 0 0 0

Bits 11:0 – UBRR0[11:0] USART Baud Rate

This is a 12-bit register which contains the USART baud rate. The UBRR0H contains the four most

significant bits and the UBRR0L contains the eight least significant bits of the USART 0 baud rate.

Ongoing transmissions by the transmitter and receiver will be corrupted if the baud rate is changed.

Writing UBRR0L will trigger an immediate update of the baud rate prescaler.