CD2481
—
Programmable Four-Channel Communications Controller
120
Datasheet
COR2
–
X.21 Mode
Bits 7:6
Reserved
–
must be zero
.
Bit 5
Embedded transmitter command enable
If set, embedded command in the FIFO is detected and acted upon.
Bit 4:0
Reserved
–
must be zero
.
FIFO Data Sequence to Implement the Embedded Transmit Command
In X.21 mode, this feature is provided to simplify the transmission of both repetitive data and data
synchronized to the
‘
C
’
lead. The command is a sequence of four consecutive bytes supplied as
normal transmit data by the host processor. The sequence of bytes placed in the data stream to
implement this are:
Byte1
This must be equal to 80 hex to start a command sequence.
Byte 2
This byte indicates the required state of the
‘
C
’
lead to be synchronized with the
transmit data.
00 = set the
‘
C
’
lead to OFF
01 = set the
‘
C
’
lead to ON
02
–
FF = reserved, do not use
Byte 3
This is the required data character for transmission. It is sent as an 8-bit character
without parity (any required parity should be included in the character by the host).
Byte 4
This is the count of the number of times the character should be sent. If set to
‘
0
’
, the
character is sent continuously until more data is provided to the transmitter (but
always a minimum of three times).
COR2
–
A
sync-HDLC / PPP Mode
Register Name: COR2
Register Description: Channel Option Register 2
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
14
Motorola Hex Address: x
’
17
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
ETC
0
0
0
0
0
Register Name: COR2
Register Description: Channel Option Register 2
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
14
Motorola Hex Address: x
’
17
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
IXM
TxIBE
0
0
RLM
RtsAO
CtsAE
DsrAE