CD2231 Intel Corporation, CD2231 Datasheet - Page 116

• Manufacturer Part Number: CD2231
• Description: CD2231 Intelligent Two-channel Lan And Wan Communications Controller
• Manufacturer: Intel Corporation

CD2231 — Intelligent Two-Channel LAN and WAN Communications Controller
8.4.2.2
116
Register Name: STCR
Register Description: Special Transmit Command
Default Value: x’00
Access: Byte Read/Write
Bit 7
0
Bit 0
NOTE: The user should not use the send XON/XOFF commands if automatic in-band flow control is enabled
SLIP/MNP 4 Mode
SLIP, MNP4, and Automatic In-Band Flow Control modes are only available on Revision B and
later devices.
Special characters can be transmitted preemptively (ahead of any characters in the transmit FIFO)
upon commands described below. When the special character is transmitted, the STCR is cleared
by the device.
Bit 7
Bit 6
Bits 5:4
Bit 3
Bit 2
Bits 1:0
AbortTx
Bit 6
(Asynchronous modes only) in COR5.
Xoff – Send XOFF
Causes the transmission of an XOFF (cntl-S or hex 13).
The command structure associated with the sndsp Control bit is:
Reserved – must be ‘0’.
Abort
Transmission of the two-character sequence (7D–7E) aborts the current transmit
frame. All data in the FIFO following the abort is discarded. If DMA is used, the
remaining data up to the EOF is discarded.
Reserved – must be ‘0’.
SndSpc – Send special character command
When clear, the frame, Xon, and Xoff bits described below have no meaning.
When set, the host should also set one of the following bits: frame, Xon, or Xoff.
Frame – Send framing error
Causes the next character in the transmit stream to be sent with an incorrect stop bit
(stop bit is ‘0’).
This bit is intended as a test function. Unlike the Abort bit, this bit does not terminate
the transmission.
Reserved – must be ‘0’.
Bit 5
sndsp
0
0
1
1
1
frame
Bit 4
X
1
0
0
0
Xon
SndSpc
X
X
1
0
Bit 3
Xoff
X
X
X
1
Frame
Bit 2
Action
Send Special Disabled
Send one character with FE
Send Xon
Send Ooff
Motorola Hex Address: x’12
Bit 1
0
Intel Hex Address: x’11
Datasheet
Bit 0
0