ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 709

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

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

6430D–ATARM–25-Mar-11
6430D–ATARM–25-Mar-11
If STTTO is performed, the counter clock is stopped until a first character is received. The idle
state on RXD before the start of the frame does not provide a time-out. This prevents having to
obtain a periodic interrupt and enables a wait of the end of frame when the idle state on RXD is
detected.
If RETTO is performed, the counter starts counting down immediately from the value TO. This
enables generation of a periodic interrupt so that a user time-out can be handled, for example
when no key is pressed on a keyboard.
Figure 35-24
Figure 35-24. Receiver Time-out Block Diagram
Table 35-11
Table 35-11. Maximum Time-out Period
• Obtain an interrupt while no character is received. This is performed by writing US_CR with
RETTO
on RXD before a new character is received will not provide a time-out. This prevents having
to handle an interrupt before a character is received and allows waiting for the next idle state
on RXD after a frame is received.
the RETTO (Reload and Start Time-out) bit to 1. If RETTO is performed, the counter starts
counting down immediately from the value TO. This enables generation of a periodic interrupt
so that a user time-out can be handled, for example when no key is pressed on a keyboard.
Character
Received
Baud Rate
STTTO
gives the maximum time-out period for some standard baud rates.
bit/sec
14400
19200
28800
33400
1 200
2 400
4 800
9 600
shows the block diagram of the Receiver Time-out feature.
600
1
D
Clear
Q
Baud Rate
Clock
Clock
Bit Time
1 667
833
417
208
104
μs
69
52
35
30
16-bit Time-out
Counter
TO
Load
16-bit
SAM3U Series
SAM3U Series
Value
0
Time-out
109 225
54 613
27 306
13 653
6 827
4 551
3 413
2 276
1 962
ms
=
TIMEOUT
709
709