A000047 Arduino, A000047 Datasheet - Page 224

• Manufacturer Part Number: A000047
• Description: MCU, MPU & DSP Development Tools Mega2560
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000047

• Processor To Be Evaluated: ATmega2560
• Interface Type: USB, I2C, SPI
• Dimensions: 4 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega2560

21.9.3
2549M–AVR–09/10
UCSRnB – USART Control and Status Register n B
• Bit 3 – DORn: Data OverRun
This bit is set if a Data OverRun condition is detected. A Data OverRun occurs when the receive
buffer is full (two characters), it is a new character waiting in the Receive Shift Register, and a
new start bit is detected. This bit is valid until the receive buffer (UDRn) is read. Always set this
bit to zero when writing to UCSRnA.
• Bit 2 – UPEn: USART Parity Error
This bit is set if the next character in the receive buffer had a Parity Error when received and the
Parity Checking was enabled at that point (UPMn1 = 1). This bit is valid until the receive buffer
(UDRn) is read. Always set this bit to zero when writing to UCSRnA.
• Bit 1 – U2Xn: Double the USART Transmission Speed
This bit only has effect for the asynchronous operation. Write this bit to zero when using syn-
chronous operation.
Writing this bit to one will reduce the divisor of the baud rate divider from 16 to 8 effectively dou-
bling the transfer rate for asynchronous communication.
• Bit 0 – MPCMn: Multi-processor Communication Mode
This bit enables the Multi-processor Communication mode. When the MPCMn bit is written to
one, all the incoming frames received by the USART Receiver that do not contain address infor-
mation will be ignored. The Transmitter is unaffected by the MPCMn setting. For more detailed
information see
• Bit 7 – RXCIEn: RX Complete Interrupt Enable n
Writing this bit to one enables interrupt on the RXCn Flag. A USART Receive Complete interrupt
will be generated only if the RXCIEn bit is written to one, the Global Interrupt Flag in SREG is
written to one and the RXCn bit in UCSRnA is set.
• Bit 6 – TXCIEn: TX Complete Interrupt Enable n
Writing this bit to one enables interrupt on the TXCn Flag. A USART Transmit Complete interrupt
will be generated only if the TXCIEn bit is written to one, the Global Interrupt Flag in SREG is
written to one and the TXCn bit in UCSRnA is set.
• Bit 5 – UDRIEn: USART Data Register Empty Interrupt Enable n
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 RxDn pin when enabled. Disabling the Receiver will flush the receive buffer
invalidating the FEn, DORn, and UPEn Flags.
Bit
Read/Write
Initial Value
RXCIEn
R/W
“Multi-processor Communication Mode” on page
7
0
TXCIEn
R/W
6
0
ATmega640/1280/1281/2560/2561
UDRIEn
R/W
5
0
RXENn
R/W
4
0
TXENn
R/W
3
0
UCSZn2
R/W
2
0
221.
RXB8n
R
1
0
TXB8n
R/W
0
0
UCSRnB
224