ATMEGA645A-AU Atmel, ATMEGA645A-AU Datasheet - Page 195

• Manufacturer Part Number: ATMEGA645A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA645A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.11.4
8285B–AVR–03/11
UCSRnC – USART Control and Status Register n C
ATmega165A/165PA/325A/325PA/3250A/3250PA/6
• Bit 5 – UDRIEn: USART Data Register Empty Interrupt Enable
Writing this bit to one enables interrupt on the UDREn Flag. A Data Register Empty interrupt will
be generated only if the UDRIEn bit is written to one, the Global Interrupt Flag in SREG is written
to one and the UDREn bit in UCSRnA is set.
• Bit 4 – RXENn: Receiver Enable n
Writing this bit to one enables the USART Receiver. The Receiver will override normal port oper-
ation for the RxD pin when enabled. Disabling the Receiver will flush the receive buffer
invalidating the FEn, DORn, and UPEn Flags.
• Bit 3 – TXENn: Transmitter Enable n
Writing this bit to one enables the USART Transmitter. The Transmitter will override normal port
operation for the TxD pin when enabled. The disabling of the Transmitter (writing TXENn to
zero) will not become effective until ongoing and pending transmissions are completed, i.e.,
when the Transmit Shift Register and Transmit Buffer Register do not contain data to be trans-
mitted. When disabled, the Transmitter will no longer override the TxD port.
• Bit 2 – UCSZn2: Character Size n
The UCSZn2 bits combined with the UCSZ1n:0 bit in UCSRnC sets the number of data bits
(Character SiZe) in a frame the Receiver and Transmitter use.
• Bit 1 – RXB8n: Receive Data Bit 8 n
RXB8n is the ninth data bit of the received character when operating with serial frames with nine
data bits. Must be read before reading the low bits from UDRn.
• Bit 0 – TXB8n: Transmit Data Bit 8 n
TXB8n 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 UDRn.
• Bit 6 – UMSELn: USART Mode Select n
This bit selects between asynchronous and synchronous mode of operation.
Table 19-8.
• Bit 5:4 – UPMn[1:0]: Parity Mode
These bits enable and set type of parity generation and check. If enabled, the Transmitter will
automatically generate and send the parity of the transmitted data bits within each frame. The
Bit
(0xC2)
Read/Write
Initial Value
UMSELn
0
1
UMSELn Bit Settings
R
7
–
0
UMSELn
R/W
6
0
Mode
Asynchronous Operation
Synchronous Operation
UPMn1
R/W
5
0
UPMn0
R/W
4
0
USBSn
R/W
3
0
UCSZn1
R/W
2
1
UCSZn0
R/W
1
1
UCPOLn
R/W
0
0
UCSRnC
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