ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 707

KIT EVAL FOR AT91SAM3U CORTEX

ATSAM3U-EK

Manufacturer Part Number
ATSAM3U-EK
Description
KIT EVAL FOR AT91SAM3U CORTEX
Manufacturer
Atmel
Type
MCUr
Datasheets

Specifications of ATSAM3U-EK

Contents
Board
Processor To Be Evaluated
SAM3U
Data Bus Width
32 bit
Interface Type
RS-232, USB
Operating Supply Voltage
3 V
Silicon Manufacturer
Atmel
Core Architecture
ARM
Core Sub-architecture
Cortex - M3
Silicon Core Number
SAM3U4E
Silicon Family Name
SAM3U
Kit Contents
Board CD Docs
Rohs Compliant
Yes
For Use With/related Products
AT91SAM3U
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATSAM3U-EK
Manufacturer:
Atmel
Quantity:
10
35.7.3.9
35.7.3.10
6430D–ATARM–25-Mar-11
6430D–ATARM–25-Mar-11
Multidrop Mode
Transmitter Timeguard
Figure 35-22. Parity Error
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the
USART runs in Multidrop Mode. This mode differentiates the data characters and the address
characters. Data is transmitted with the parity bit to 0 and addresses are transmitted with the
parity bit to 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 to 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit
RSTSTA to 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this
case, the next byte written to US_THR is transmitted as an address. Any character written in
US_THR without having written the command SENDA is transmitted normally with the parity
to 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 (US_TTGR). When this field is programmed to zero no timeguard is generated. Otherwise,
the transmitter holds a high level on TXD after each transmitted byte during the number of bit
periods programmed in TG in addition to the number of stop bits.
As illustrated in
the programming of a timeguard. TXRDY rises only when the start bit of the next character is
sent, and thus remains to 0 during the timeguard transmission if a character has been written in
US_THR. TXEMPTY remains low until the timeguard transmission is completed as the time-
guard is part of the current character being transmitted.
Baud Rate
RXRDY
US_CR
PARE
Clock
Write
Figure
RXD
35-23, the behavior of TXRDY and TXEMPTY status bits is modified by
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
Parity
Bad
Bit
Stop
Bit
SAM3U Series
SAM3U Series
RSTSTA = 1
707
707

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