atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 181

• Manufacturer Part Number: atmega3250v-8auatmega325v-8ai
• Description: Atmega3250 8-bit Microcontroller With In-system Programmable Flash
• Manufacturer: ATMEL Corporation

20.11.4
2570L–AVR–08/07
UCSRnC – USART Control and Status Register n C
• Bit 2 – UCSZn2: Character Size
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
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
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
This bit selects between asynchronous and synchronous mode of operation.
Table 20-8.
• Bit 5:4 – UPMn1:0: 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
Receiver will generate a parity value for the incoming data and compare it to the UPMn0 setting.
If a mismatch is detected, the UPEn Flag in UCSRnA will be set.
Table 20-9.
Bit
Read/Write
Initial Value
UPMn1
UMSELn
0
0
1
1
0
1
R
7
–
0
UMSEL Bit Settings
UPM Bits Settings
UMSELn
R/W
6
0
Mode
Asynchronous Operation
Synchronous Operation
UPMn1
UPMn0
R/W
5
0
0
1
0
1
UPMn0
R/W
4
0
ATmega325/3250/645/6450
USBSn
Parity Mode
Disabled
Reserved
Enabled, Even Parity
Enabled, Odd Parity
R/W
3
0
UCSZn1
R/W
2
1
UCSZn0
R/W
1
1
UCPOLn
R/W
0
0
UCSRnC
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