ATMEGA8_08 Datasheet, PDF (157/308 Pages) ATMEL Corporation – 8-bit with 8K Bytes In-System Programmable Flash

ATmega8(L)
• Bit 5:4 – UPM1:0: 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 UPM0 setting.
If a mismatch is detected, the PE Flag in UCSRA will be set.
Table 56. UPM Bits Settings
UPM1
UPM0
0
0
0
1
1
0
1
1
Parity Mode
Disabled
Reserved
Enabled, Even Parity
Enabled, Odd Parity
• Bit 3 – USBS: Stop Bit Select
This bit selects the number of stop bits to be inserted by the trAnsmitter. The Receiver ignores
this setting.
Table 57. USBS Bit Settings
USBS
0
1
Stop Bit(s)
1-bit
2-bit
• Bit 2:1 – UCSZ1:0: Character Size
The UCSZ1:0 bits combined with the UCSZ2 bit in UCSRB sets the number of data bits (Char-
acter Size) in a frame the Receiver and Transmitter use.
Table 58. UCSZ Bits Settings
UCSZ2
UCSZ1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
UCSZ0
0
1
0
1
0
1
0
1
Character Size
5-bit
6-bit
7-bit
8-bit
Reserved
Reserved
Reserved
9-bit
• Bit 0 – UCPOL: Clock Polarity
2486T–AVR–05/08
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