Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
205
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
• Bit 6 – TXCIEn: TX Complete Interrupt Enable
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.
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 – UDRIE: 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 UDRIE bit is written to one, the Global Interrupt Flag in SREG is written to one and the UDREn bit in
UCSRnA is set.
only if the UDRIE 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
Writing this bit to one enables the USART Receiver in MSPIM mode. The Receiver will override normal port
operation for the RxDn pin when enabled. Disabling the Receiver will flush the receive buffer. Only enabling the
receiver in MSPI mode (i.e. setting RXENn=1 and TXENn=0) has no meaning since it is the transmitter that
controls the transfer clock and since only master mode is supported.
operation for the RxDn pin when enabled. Disabling the Receiver will flush the receive buffer. Only enabling the
receiver in MSPI mode (i.e. setting RXENn=1 and TXENn=0) has no meaning since it is the transmitter that
controls the transfer clock and since only master mode is supported.
• Bit 3 – TXENn: Transmitter Enable
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.
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 2:0 – Reserved Bits in MSPI mode
When in MSPI mode, these bits are reserved for future use. For compatibility with future devices, these bits
must be written to zero when UCSRnB is written.
must be written to zero when UCSRnB is written.
21.8.4 UCSRnC – USART MSPIM Control and Status Register n C
• Bit 7:6 – UMSELn1:0: USART Mode Select
These bits select the mode of operation of the USART as shown in
. See
for full description of the normal USART operation. The MSPIM is
enabled when both UMSELn bits are set to one. The UDORDn, UCPHAn, and UCPOLn can be set in the same
write operation where the MSPIM is enabled.
write operation where the MSPIM is enabled.
Bit
7
6
5
4
3
2
1
0
UMSELn1
UMSELn0
–
–
–
UDORDn
UCPHAn
UCPOLn
UCSRnC
Read/Write
R/W
R/W
R
R
R
R/W
R/W
R/W
Initial Value
0
0
0
0
0
1
1
0
Table 21-4.
UMSELn Bits Settings
UMSELn1
UMSELn0
Mode
0
0
Asynchronous USART
0
1
Synchronous USART
1 0 Reserved
1 1 Master
SPI
(MSPIM)