Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet
Product codes
AT91SAM9N12-EK
773
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
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.
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.
periodic interrupt so that a user time-out can be handled, for example when no key is pressed on a keyboard.
shows the block diagram of the Receiver Time-out feature.
Figure 40-24. Receiver Time-out Block Diagram
gives the maximum time-out period for some standard baud rates.
Table 40-10. Maximum Time-out Period
Baud Rate (Bit/s)
Bit Time (µs)
Time-out (ms)
600
1,667
109,225
1,200
833
54,613
2,400
417
27,306
4,800
208
13,653
9,600
104
6,827
14,400
69
4,551
19,200
52
3,413
28,800
35
2,276
38,400
26
1,704
56,000
18
1,170
57,600
17
1,138
200,000
5
328
16-bit Time-out
Counter
0
TO
TIMEOUT
Baud Rate
Clock
=
Character
Received
RETTO
Load
Clock
16-bit
Value
STTTO
D
Q
1
Clear