Техническая Спецификация для Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI
Модели
MEGA328P-XMINI
194
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
• 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.
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.
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.
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.
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.
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.
bits. Must be written before writing the low bits to UDRn.
20.11.4 UCSRnC – USART Control and Status Register n C
• Bits 7:6 – UMSELn1:0 USART Mode Select
These bits select the mode of operation of the USARTn as shown in
.
Note:
1.
See
for full description of the Master SPI Mode (MSPIM) operation
Bit
7
6
5
4
3
2
1
0
UMSELn1
UMSELn0
UPMn1
UPMn0
USBSn
UCSZn1
UCSZn0
UCPOLn
UCSRnC
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
1
1
0
Table 20-8.
UMSELn Bits Settings
UMSELn1
UMSELn0
Mode
0
0
Asynchronous USART
0
1
Synchronous USART
1
0
(Reserved)
1
1
Master SPI (MSPIM)