Datasheet

Start StartTX
CTS
Byte0–7
Stop Stop
Byte0–7
T0467-01
D7D0
D7D0
RX
RTS
TX
CTS
TX
CTS
RX
RTS
UART 1 UART 2
RX
FIFO
TX
FIFO
Serialto
Parallel
Flow
Control
Parallelto
Serial
Flow
Control
Parallelto
Serial
Flow
Control
Serialto
Parallel
Flow
Control
TX
FIFO
RX
FIFO
B0416-01
TL16C752B
SLLS405C –DECEMBER 1999–REVISED JUNE 2010 www.ti.com
auto-CTS
The transmitter circuitry checks CTS before sending the next data byte. When CTS is active, the transmitter
sends the next byte. To stop the transmitter from sending the following byte. CTS must be deasserted before the
middle of the last stop bit that is currently being sent. The auto-CTS function reduces interrupts to the host
system. When flow control is enabled, the CTS state changes and need not trigger host interrupts because the
device automatically controls its own transmitter. Without auto-CTS, the transmitter sends any data present in the
transmit FIFO and a receiver overrun error can result. Figure 2 shows CTS functional timing, and Figure 3 shows
an example of autoflow control.
A. When CTS is low, the transmitter keeps sending serial data out
B. When CTS goes high before the middle of the last stop bit of the current byte, the transmitter finishes sending the
current byte but it does not send the next byte.
C. When CTS goes from high to low, the transmitter begins sending data again.
Figure 2. CTS Functional Timing
Figure 3. Autoflow Control (Auto-RTS and Auto-CTS) Examplev
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