UART/Autobaud Control and Status Registers
12-30
Table 12–25. Enhanced Feature Register (EFR) (Continued)
Bit
Reset
Value
R/W
Function
Value
Name
5
SPECIAL_CHAR_
DETECT
0
Normal operation
R/W
0
1
Special character detect enable
Received data is compared with XOFF2 data.
If a match occurs, the received data is
transferred to FIFO and IIR bit 4 is set to 1 to
indicate a special character has been
detected.
4
ENHANCED_EN
Enhanced functions write enable bit
R/W
0
0
Disables writing to IER bits 4 - 7, FCR bits
4 - 5, and MCR bits 5 - 7.
1
Enables writing to IER bits 4 - 7, FCR bits 4 - 5,
and MCR bits 5 - 7.
3–0
SW_FLOW_CON-
TROL
Combinations of software flow control can be
selected by programming bit 3 - bit 0. See
Section 12.5.10, Software Flow Control.
R/W
0
Table 12–26. EFR[0 - 3]: Software Flow Control Options
Bit 3
Bit 2
Bit 1
Bit 0
TX,RX Software Flow Controls
0
0
X
X
No transmit flow control
1
0
X
X
Transmit XON1, XOFF1
0
1
X
X
Transmit XON2, XOFF2
1
1
X
X
Transmit XON1, XON2: XOFF1, XOFF2
X
X
0
0
No receive flow control
X
X
1
0
Receiver compares XON1, XOFF1
X
X
0
1
Receiver compares XON2, XOFF2
X
X
1
1
Receiver compares XON1, XON2: XOFF1, XOFF2
Note:
XON1 and XON2 must be set to different values if the software flow control is enabled.