NEX ROBOTICS Fire Bird V ATMEGA2560 Software Manual page 105

Fire Bird V ATMEGA2560 Software Manual
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
operation for the RxDn 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 TxDn 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
transmitted. When disabled, the Transmitter will no longer override the TxDn port.
Bit 2 – UCSZn2: Character Size n
The UCSZn2 bits combined with the UCSZn1:0 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.
© NEX Robotics Pvt. Ltd. and ERTS Lab IIT Bombay, INDIA 105