CD2481 Datasheet, PDF (125/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

Programmable Four-Channel Communications Controller — CD2481
Bit 5
Bit 4
Bit 3
Bit 2
Bits 1:0
FCS preset
0 = FCS is preset to all ‘0’s.
1 = FCS is preset to all ‘1’s.
FCS mode
0 = Normal FCS mode. The CD2481 generates and appends CRC on transmit and
validates CRC on receiving, using the CRC polynomial selected through CRC Poly-
nomial Select register.
1 = Disable FCS generation and checking. The CD2481 treats the entire frame as
data.
Idle mode
0 = Idle in SYN.
1 = Idle in Mark.
Disable CRC transmission on all Bisync frames
0 = disable function
1 = CRC will not be transmitted on any frames
Pad count – Transmit frame leading pads
Specifies the number of pad characters to be sent when coming out of Mark Idle
mode.
npad1
0
0
1
1
npad0
0
1
0
1
Number of
leading pads
0
1
2
3
COR3 – Asynchronous Mode
Register Name: COR3
Register Description: Channel Option Register 3
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
ESCDE
RngDE
FCT
SCDE
Bit 3
Splstp
Intel Hex Address: x’15
Motorola Hex Address: x’16
Bit 2
Stop2
Bit 1
Stop1
Bit 0
Stop0
Bit 7
ESCDE – Extended special character detect enable
0 = Special character detect for SCHR3 and SCHR4 is disabled.
1 = Special character detect for SCHR3 and SCHR4 is enabled; a special character
interrupt is generated following the receipt of a character matching SCHR3 or
SCHR4.
Bit 6
RngDE – Range detect enable
0 = Range detect disabled.
Datasheet
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