ATEVK1105 Atmel, ATEVK1105 Datasheet - Page 321

• Manufacturer Part Number: ATEVK1105
• Description: KIT EVAL FOR AT32UC3A0
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1105

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A0512
• Processor Series: AVR
• Data Bus Width: 32 bit
• Interface Type: USART, TWI, USB, SPI, Ethernet
• Operating Supply Voltage: 3.3 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A0512
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 26-22. Parity Error
26.7.4.3
26.7.4.4
32058J–AVR32–04/11
Multidrop Mode
Transmitter Timeguard
Baud Rate
If the PAR field in the Mode Register (MR) is programmed to the value 0x6 or 0x07, the USART
runs in Multidrop Mode. This mode differentiates the data characters and the address charac-
ters. Data is transmitted with the parity bit at 0 and addresses are transmitted with the parity bit
at 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when
the parity bit is high and the transmitter is able to send a character with the parity bit high when
the Control Register is written with the SENDA bit at 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit
RSTSTA at 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to CR. In this case,
the next byte written to THR is transmitted as an address. Any character written in THR without
having written the command SENDA is transmitted normally with the parity at 0.
The timeguard feature enables the USART interface with slow remote devices.
The timeguard function enables the transmitter to insert an idle state on the TXD line between
two characters. This idle state actually acts as a long stop bit.
The duration of the idle state is programmed in the TG field of the Transmitter Timeguard Regis-
ter (TTGR). When this field is programmed at zero no timeguard is generated. Otherwise, the
transmitter holds a high level on TXD after each transmitted byte during the number of bit peri-
ods programmed in TG in addition to the number of stop bits.
As illustrated in
modified by the programming of a timeguard. TXRDY rises only when the start bit of the next
character is sent, and thus remains at 0 during the timeguard transmission if a character has
been written in THR. TXEMPTY remains low until the timeguard transmission is completed as
the timeguard is part of the current character being transmitted.
RXRDY
US_CR
PARE
Clock
Write
RXD
Start
Bit
D0
Figure 26-23 on page
D1
D2
D3
D4
D5
D6
322, the behavior of TXRDY and TXEMPTY status bits is
D7
Parity
Bad
Bit
Stop
Bit
RSTSTA = 1
AT32UC3A
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