CD2481 Datasheet, PDF (124/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

CD2481 — Programmable Four-Channel Communications Controller
Bit 6
Bit 5
Bit 4
Bit 3
Bits 2:0
alt1 – send sync pattern
1 = AAh (Manchester/NRZ encoding) is sent as pad character.
0 = 00h (NRZI encoding) is sent as pad character.
FCS preset
0 = FCS is preset to all ‘1’s (CRC V.41).
1 = FCS is preset to all ‘0’s (CRC-16).
FCS mode
1 = Disables FCS generation and checking. The CD2481 treats the entire frame as
data.
0 = Normal FCS mode. The CD2481 generates and appends CRC on transmit and
validates CRC on receive using the CRC polynomial selected through the CRC Poly-
nomial Select register.
Idle mode
0 = idle in Flag mode
1 = idle in Mark mode
Character Count – specifies the number of synchronous characters sent.
npad2
npad1
0
0
0
0
0
1
0
1
1
0
101–111 are reserved.
npad0
0
1
0
1
0
Reserved
1 pad character sent
2 pad characters sent
3 pad characters sent
4 pad characters sent
COR3 – Bisynchronous 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
Sndpad
S55
FCSPre
FCS
Bit 3
Idle
Intel Hex Address: x’15
Motorola Hex Address: x’16
Bit 2
DisCRC
Bit 1
npad1
Bit 0
npad0
Bit 7
Bit 6
Send pad character
0 = CD2481 does not send any pad characters.
1 = CD2481 sends pad characters before sending SYN when coming out of the Mark
Idle mode.
S55 = Send pad pattern
0 = hex AA is sent as pad character.
1 = hex 55 is sent as pad character.
124
Datasheet