Datasheet

167

ATmega8535(L)

2502K–AVR–10/06

TXB8 is the ninth data bit in the character to be transmitted when operating with serial

frames with nine data bits. Must be written before writing the low bits to UDR.

USART Control and Status

(1)

Note: 1. The UCSRC Register shares the same I/O location as the UBRRH Register. See the

“Accessing UBRRH/UCSRC Registers” on page 163 section which describes how to

access this register.

• Bit 7 – URSEL: Register Select

This bit selects between accessing the UCSRC or the UBRRH Register. It is read as

one when reading UCSRC. The URSEL must be one when writing the UCSRC.

• Bit 6 – UMSEL: USART Mode Select

This bit selects between asynchronous and synchronous mode of operation.

Bit 76543210

URSEL UMSEL UPM1 UPM0 USBS UCSZ1 UCSZ0 UCPOL UCSRC

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial Value10000110

Table 64. UMSEL Bit Settings

UMSEL Mode

0 Asynchronous Operation

1 Synchronous Operation