ATMEGA165PV-8MNR Atmel, ATMEGA165PV-8MNR Datasheet - Page 183

• Manufacturer Part Number: ATMEGA165PV-8MNR
• Description: IC MCU AVR 16K 8MHZ 64MLF
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA165PV-8MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.11 Register Description
18.11.1
18.11.2
8019K–AVR–11/10
UDRn – USART I/O Data Register n
UCSRnA – USART Control and Status Register n A
The USART Transmit Data Buffer Register and USART Receive Data Buffer Registers share the
same I/O address referred to as USART Data Register or UDRn. The Transmit Data Buffer Reg-
ister (TXBn) will be the destination for data written to the UDRn Register location. Reading the
UDRn Register location will return the contents of the Receive Data Buffer Register (RXBn).
For 5-bit, 6-bit, or 7-bit characters the upper unused bits will be ignored by the Transmitter and
set to zero by the Receiver.
The transmit buffer can only be written when the UDREn Flag in the UCSRnA Register is set.
Data written to UDRn when the UDREn Flag is not set, will be ignored by the USART Transmit-
ter. When data is written to the transmit buffer, and the Transmitter is enabled, the Transmitter
will load the data into the Transmit Shift Register when the Shift Register is empty. Then the
data will be serially transmitted on the TxD pin.
The receive buffer consists of a two level FIFO. The FIFO will change its state whenever the
receive buffer is accessed. Due to this behavior of the receive buffer, do not use Read-Modify-
Write instructions (SBI and CBI) on this location. Be careful when using bit test instructions
(SBIC and SBIS), since these also will change the state of the FIFO.
• Bit 7 – RXCn: USART Receive Complete
This flag bit is set when there are unread data in the receive buffer and cleared when the receive
buffer is empty (that is, does not contain any unread data). If the Receiver is disabled, the
receive buffer will be flushed and consequently the RXCn bit will become zero. The RXCn Flag
can be used to generate a Receive Complete interrupt (see description of the RXCIEn bit).
• Bit 6 – TXCn: USART Transmit Complete n
This flag bit is set when the entire frame in the Transmit Shift Register has been shifted out and
there are no new data currently present in the transmit buffer (UDRn). The TXCn Flag bit is auto-
matically cleared when a transmit complete interrupt is executed, or it can be cleared by writing
a one to its bit location. The TXCn Flag can generate a Transmit Complete interrupt (see
description of the TXCIEn bit).
Bit
(0xC6)
Read/Write
Initial Value
Bit
(0xC0)
Read/Write
Initial Value
RXCn
R/W
7
0
R
7
0
TXCn
R/W
R/W
6
0
6
0
UDREn
R/W
5
0
R
5
1
R/W
4
0
FEn
R
RXBn[7:0]
TXBn[7:0]
4
0
R/W
DORn
3
0
R
3
0
R/W
UPEn
2
0
R
2
0
R/W
1
0
U2Xn
ATmega165P
R/W
1
0
R/W
MPCMn
0
0
R/W
0
0
UDRn (Read)
UDRn (Write)
UCSRnA
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