CD2401 Intel, CD2401 Datasheet - Page 94

• Manufacturer Part Number: CD2401
• Description: Multi-protocol Communications Controller
• Manufacturer: Intel

CD2401 — Multi-Protocol Communications Controller
8.2.2
94
Register Name: COR1
Register Description: Channel Option 1
Default Value: x’00
Access: Byte Read/Write
AFLO
Bit 7
Channel Option Register 1 (COR1)
COR1 — HDLC Mode
An Initialization command must be given to CD2401 through the CCR if any options specified in
this register are changed.
Bit 7
Bit 6
Bits 5:4
Bits 3:0
ClrDet
Bit 6
Address Field Length Option
0 = address field is one octet in length
1 = address field is two octets in length
Clear Detect for X.21 data transfer phase
0 = clear detect disabled
1 = clear detect enabled
A clear is defined as two consecutive all zeros receive characters, with the CTS* pin
high.
Addressing modes [1:0]
00 = no address recognition
01 = 4
10 = 2
If this bit is set, RFARs should contain the address to be matched. If AFLO
(COR1[7]) is set to ‘1’, an address match is made against the RFAR1 and RFAR2
pair, or the RFAR3 and RFAR4 pair.
Inter-frame flag option [3:0]
These bits define the minimum number of flags transmitted before a frame is started.
The minimum number of opening flags always precede a frame when idle in mark
is set, or always separates two consecutively transmitted frames. No restriction is
placed on the number of flags between received frames.
AdMde1
Bit 5
Flag3
0
0
1
1 byte
2 byte.
Flag2
AdMde0
0
0
1
Bit 4
through
Flag1
0
0
1
Flag3
Bit 3
Flag0
0
1
1
Minimum of one opening flag, with shared
closing/opening flags permitted.
Minimum number of opening flags sent.
Flag2
Bit 2
Function
Motorola Hex Address: x’10
Flag1
Bit 1
Intel Hex Address: x’13
Datasheet
Flag0
Bit 0