
CD2481
—
Programmable Four-Channel Communications Controller
128
Datasheet
Bit 5
RxChk
–
Receive FCS check enabled
When clear, the channel does not test the 2-byte FCS field. All frame data characters
are given to the host.
When set, the channel tests the 2-byte FCS field.
Bit 4
TxGen
–
Transmit FCS enabled
When clear, the channel does not add the 2-byte FCS field.
When set, the channel adds the 2-byte FCS field at the end of the frame.
Bits 3:0
npad3, npad2, npad1, npad0
–
Transmit frame leading pads
The number of character times preceding any frame transmission. A character time
is 10 bit times. All zeros in this field disables the leading pads.
COR3
–
SLIP Mode
Note:
SLIP, MNP4, and Automatic In-Band Flow Control modes are only available on Revision B and
later devices.
Bit 7
Stop2
0 = 1 Stop bit
1 = 2 Stop bit
Bits 6:4
Reserved
–
must be zero
.
Bits 3:0
npad3, npad2, npad1, npad0
–
Transmit frame leading pads
The number of character times preceding any frame transmission. A character time
is 10 bit times. All zeros in this field disables the leading pads.
npad3
npad2
npad1
npad0
Number of
leading pads
0
0
0
0
0
0
0
0
1
1
0
0
1
0
2
1
1
1
1
15
Register Name: COR3
Register Description: Channel Option Register 3
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
15
Motorola Hex Address: x
’
16
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Stop2
0
0
0
npad3
npad2
npad1
npad0