AT32UC3L064-D3HES ATMEL [ATMEL Corporation], AT32UC3L064-D3HES Datasheet - Page 377

• Manufacturer Part Number: AT32UC3L064-D3HES
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 20-11. Timeguard Operations
20.6.3.8
32099D–06/2010
Baud Rate
TXEMPTY
TXRDY
Clock
Write
THR
TXD
Receiver Time-out
Start
Bit
D0
D1
Table 20-5
in relation to the function of the Baud Rate.
Table 20-5.
The Receiver Time-out provides support in handling variable-length frames. This feature detects
an idle condition on the RXD line. When a time-out is detected, the bit TIMEOUT in the Channel
Status Register (CSR) rises and can generate an interrupt, thus indicating to the driver an end of
frame.
The time-out delay period (during which the receiver waits for a new character) is programmed
in the TO field of the Receiver Time-out Register (RTOR). If the TO field is programmed at 0, the
Receiver Time-out is disabled and no time-out is detected. The TIMEOUT bit in CSR remains at
0. Otherwise, the receiver loads a counter with the value programmed in TO. This counter is
decremented at each bit period and reloaded each time a new character is received. If the coun-
ter reaches 0, the TIMEOUT bit in the Status Register rises. Then, the user can either:
D2
• Stop the counter clock until a new character is received. This is performed by writing the
Control Register (CR) with the STTTO (Start Time-out) bit at 1. In this case, the idle state on
RXD before a new character is received will not provide a time-out. This prevents having to
D3
D4
D5
Baud Rate
indicates the maximum length of a timeguard period that the transmitter can handle
115200
Bit/sec
14400
19200
28800
33400
56000
57600
1 200
9 600
D6
Maximum Timeguard Length Depending on Baud Rate
D7
Parity
Bit
Stop
Bit
TG = 4
Start
Bit
D0
Bit time
69.4
52.1
34.7
29.9
17.9
17.4
D1
833
104
8.7
µs
D2
D3
D4
AT32UC3L016/32/64
D5
D6
D7
Parity
Bit
Stop
Bit
Timeguard
212.50
17.71
13.28
26.56
8.85
7.63
4.55
4.43
2.21
ms
TG = 4
377