CD2231 Intel Corporation, CD2231 Datasheet - Page 98

• Manufacturer Part Number: CD2231
• Description: CD2231 Intelligent Two-channel Lan And Wan Communications Controller
• Manufacturer: Intel Corporation

CD2231 — Intelligent Two-Channel LAN and WAN Communications Controller
8.2.5
98
Register Name: COR4
Register Description: Channel Option Register 4 (Modem Change Options
and FIFO Transfer Threshold)
Default Value: x’00
Access: Byte Read/Write
DSRzd
Bit 7
Bit 5
Bit 4
Bit 3
Bits 2:0
Channel Option Register 4 (COR4)
(Modem Change Options and FIFO Transfer Threshold)
Bit 7
Bit 6
Bit 5
Bit 4
CDzd
Bit 6
FCT – Flow Control Transparency mode
0 = Flow control characters received are passed to the host by receive exception
interrupts.
1 = Flow control characters received are not passed to the host.
This bit has no effect unless both TxIBE (COR2[6]) and SCDE (COR3[4]) are set.
SCDE – Special character detection
0 = Special character detect for SCHR1 and 2 is disabled.
1 = Special character detect for SCHR1 and 2 is enabled.
This bit must be set along with TxIBE (COR2[6]) before FCT (COR3[5]) becomes
effective.
Splstp – Special character I-strip
When set, this bit causes the receive character to be I-stripped (COR3[7] set to ‘0’)
for the special character matching functions only. The character passed to the host is
unaffected. This function allows special character processing of data without know-
ing if the data is 8 bits with no parity or 7 bit with parity.
Stop2, Stop1, Stop0 – Stop bit length
Specifies the length of the Stop bit.
DSRzd = 1
Detect one-to-zero transition on the DSR* input (zero-to-one transition of DSR
(MSVR) bit)
CDzd = 1
Detect one-to-zero transition on the CD* input (zero-to-one transition of CD
(MSVR) bit)
CTSzd = 1
Detect one-to-zero transition on the CTS* input (zero-to-one transition of CTS
(MSVR) bit)
Reserved – must be ‘0’.
CTSzd
Bit 5
Stop2
0
0
1
000–001 and 110–111 are reserved.
Bit 4
Stop1
0
1
1
0
Bit 3
Stop0
0
1
0
1 stop bit
1.5 stop bits
2 stop bits
Bit 2
FIFO threshold
Stop Bit Length
Motorola Hex Address: x’15
Bit 1
Intel Hex Address: x’16
Datasheet
Bit 0