ATmega64A datasheet(200/392 Pages) ATMEL

Part #	ATmega64A

Description	8-bit Microcontroller with 64K Bytes In-System Programmable Flash

PDF	392 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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200 / 392 page

200

8160C–AVR–07/09

ATmega64A

20.11.5

UBRRnL and UBRRnH – USART Baud Rate Registers

(1)

Note:

1. UBRRH is not available in mega103 compatibility mode

• Bit 15:12 – Reserved Bits

These bits are reserved for future use. For compatibility with future devices, these bit must be

written to zero when UBRRH is written.

• Bit 11:0 – UBRRn11:0: USART Baud Rate Register

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

most significant bits, and the UBRRnL contains the eight least significant bits of the USART

baud rate. Ongoing transmissions by the Transmitter and Receiver will be corrupted if the baud

rate is changed. Writing UBRRnL will trigger an immediate update of the baud rate prescaler.

Bit

151413

1110

––––

UBRRn[11:8]

UBRRnH

UBRRn[7:0]

UBRRnL

7654

3210

Read/Write

R/W

Initial Value

0000

ATmega64A Datasheet(PDF) 200 Page - ATMEL Corporation