Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet
Product codes
ATSAM4L-XPRO
584
42023E–SAM–07/2013
ATSAM4L8/L4/L2
24.6.3.4
Receiver Time-out
The Time-out Value field in the Receiver Time-out Register (RTOR.TO) enables handling of vari-
able-length frames by detection of selectable idle durations on the RXD line. The value written to
TO is loaded to a decremental counter, and unless it is zero, a time-out will occur when the
amount of inactive bit periods matches the initial counter value. If a time-out has not occurred,
the counter will reload and restart every time a new character arrives. A time-out sets the
Receiver Time-out bit in CSR (CSR.TIMEOUT). An interrupt request is generated if the Receiver
Time-out bit in the Interrupt Mask Register (IMR.TIMEOUT) is set. Clearing TIMEOUT can be
done in two ways:
able-length frames by detection of selectable idle durations on the RXD line. The value written to
TO is loaded to a decremental counter, and unless it is zero, a time-out will occur when the
amount of inactive bit periods matches the initial counter value. If a time-out has not occurred,
the counter will reload and restart every time a new character arrives. A time-out sets the
Receiver Time-out bit in CSR (CSR.TIMEOUT). An interrupt request is generated if the Receiver
Time-out bit in the Interrupt Mask Register (IMR.TIMEOUT) is set. Clearing TIMEOUT can be
done in two ways:
• Writing a one to the Start Time-out bit (CR.STTTO). This also aborts count down until the
next character has been received.
• Writing a one to the Reload and Start Time-out bit (CR.RETTO). This also reloads the
counter and restarts count down immediately.
Figure 24-11. Receiver Time-out Block Diagram
Table 24-6.
Maximum Time-out Period
Baud Rate (bit/sec)
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
14400
69
4 551
19200
52
3 413
28800
35
2 276
33400
30
1 962
56000
18
1 170
57600
17
1 138
200000
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