CD2231 Intel Corporation, CD2231 Datasheet - Page 96
Manufacturer Part Number
CD2231 Intelligent Two-channel Lan And Wan Communications Controller
CD2231 — Intelligent Two-Channel LAN and WAN Communications Controller
Register Name: COR3
Register Description: Channel Option Register 3
Default Value: x’00
Access: Byte Read/Write
In Synchronous mode, COR3 is used to specify the learning pattern (pad character) sent by the
CD2231 to synchronize the DPLL at the remote end. The pad character (00h or AAh) sent depends
on the kind of encoding used.
Sends pad character(s)
1 = CD2231 sends pad character(s) before sending flag when coming out of the Idle-
in Mark mode.
0 = CD2231 does not send any pad character.
alt1 – send sync pattern
1 = AAh (Manchester/NRZ encoding) is sent as pad character.
0 = 00h (NRZI encoding) is sent as pad character.
0 = FCS is preset to all ‘1’s (CRC V.41).
1 = FCS is preset to all ‘0’s (CRC-16).
1 = Disables FCS generation and checking. The CD2231 treats the entire frame as
0 = Normal FCS mode. The CD2231 generates and appends CRC on transmit and
validates CRC on receive using the CRC polynomial selected through the CRC Poly-
nomial Select register.
0 = Idle-in Flag mode
1 = Idle-in Mark mode
Character Count – specifies the number of synchronous characters sent.
101–111 are reserved.
1 pad character sent
2 pad characters sent
3 pad characters sent
4 pad characters sent
Motorola Hex Address: x’16
Intel Hex Address: x’15