ATMEGA128A-AN Atmel, ATMEGA128A-AN Datasheet - Page 197

• Manufacturer Part Number: ATMEGA128A-AN
• Description: IC MCU AVR 128K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA128A-AN

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Core: AVR8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

20.9.5
8151H–AVR–02/11
UBRRnL and UBRRnH - USART Baud Rate Registers
UBRRnH is not available in mega103 compatibility mode
• Bit 15:12 – Reserved
These bits are reserved for future use. For compatibility with future devices, these bit must be
written to zero when UBRRnH is written.
• Bit 11:0 – UBRRn[11:0]: USARTn Baud Rate Register
This is a 12-bit register which contains the USARTn baud rate. The UBRRnH contains the four
most significant bits, and the UBRRnL contains the eight least significant bits of the USARTn
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
Read/Write
Initial Value
R/W
15
R
–
7
0
0
R/W
14
R
–
6
0
0
R/W
13
R
–
5
0
0
R/W
12
R
–
4
0
0
UBRRn[7:0]
R/W
R/W
11
3
0
0
R/W
R/W
10
2
0
0
UBRRn[11:8]
ATmega128A
R/W
R/W
9
1
0
0
R/W
R/W
8
0
0
0
UBRRnH
UBRRnL
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