CD2481 Datasheet, PDF (115/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

Programmable Four-Channel Communications Controller — CD2481
The minimum number of opening flags always precede a frame when idle in Mark
mode is set, or is always separated by two consecutively transmitted frames. No
restriction is placed on the number of flags between received frames.
Note: Not used in PPP, MNP4, and SLIP modes.
COR1 – Asynchronous, Bisynchronous, and X.21 Modes (Not used in PPP
mode)
Register Name: COR1
Register Description: Channel Option Register 1
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Parity
ParM1
ParM0
Ignore
Bit 3
ChL3
Intel Hex Address: x’13
Motorola Hex Address: x’10
Bit 2
ChL2
Bit 1
ChL1
Bit 0
ChL0
Bit 7
Bits 6:5
Parity
1 = odd parity
0 = even parity
Parity mode 1 and 0
Defines Parity mode for both transmitter and receiver:
Bit 4
Bits 3:0
ParM1
0
0
1
1
ParM0
0
1
0
1
Parity
no parity
force parity
(odd parity = force 1, even = force 0)
normal parity
reserved
Ignore – Ignore parity
0 = evaluate parity on received characters
1 = do not evaluate parity on received characters
Character Length
ChL3
0
0
0
0
ChL2
1
1
1
1
ChL1
0
0
1
1
Note: Not used in PPP, MNP4, and SLIP modes.
ChL0
0
1
0
1
Character Length
5 bits
6 bits
7 bits
8 bits
Datasheet
115