Datasheet

208
7766F–AVR–11/10
ATmega16/32U4
Receiver will generate a parity value for the incoming data and compare it to the UPMn setting.
If a mismatch is detected, the UPEn Flag in UCSRnA will be set.
• Bit 3 – USBSn: Stop Bit Select
This bit selects the number of stop bits to be inserted by the Transmitter. The Receiver ignores
this setting.
• Bit 2:1 – UCSZn1:0: Character Size
The UCSZn1:0 bits combined with the UCSZn2 bit in UCSRnB sets the number of data bits
(Character SiZe) in a frame the Receiver and Transmitter use.
• Bit 0 – UCPOLn: Clock Polarity
This bit is used for synchronous mode only. Write this bit to zero when asynchronous mode is
used. The UCPOLn bit sets the relationship between data output change and data input sample,
and the synchronous clock (XCKn).
Table 18-5. UPMn Bit Settings
UPMn1 UPMn0 Parity Mode
0 0 Disabled
01Reserved
1 0 Enabled, Even Parity
1 1 Enabled, Odd Parity
Table 18-6. USBS Bit Settings
USBSn Stop Bit(s)
01-bit
12-bit
Table 18-7. UCSZn Bit Settings
UCSZn2 UCSZn1 UCSZn0 Character Size
0005-bit
0016-bit
0107-bit
0118-bit
100Reserved
101Reserved
110Reserved
1119-bit
Table 18-8. UCPOLn Bit Settings
UCPOLn
Transmitted Data Changed (Output
of TxDn Pin)
Received Data Sampled (Input on
RxDn Pin)
0 Rising XCKn Edge Falling XCKn Edge
1 Falling XCKn Edge Rising XCKn Edge