CD2231

Manufacturer Part NumberCD2231
DescriptionCD2231 Intelligent Two-channel Lan And Wan Communications Controller
ManufacturerIntel Corporation
CD2231 datasheet
 


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Intelligent Two-Channel LAN and WAN Communications Controller — CD2231
Bits 2:0
Parity/framing error actions – These bits determine the action taken when a parity or
framing error is received.
Following the generation of a break-exception interrupt, a receive exception inter-
rupt is generated with RET bit (RISRl[7]) set, when the end of break is detected. The
RET interrupt must be enabled in IER[5] to enable this feature.
ParMrk
When ParMrk = 1 and ParInt = 1, each occurrence of FF hex in the data stream is
preceded by FF hex to distinguish it from a parity error sequence.
8.2.8
Channel Option Register 7 (COR7) — Async Mode Only
Register Name: COR7
Register Description: Channel Option Register 7
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
IStrip
LNE
FCErr
CR is defined as 0D hex, NL as 0A hex and NULL as 00 hex.
Bit 7
IStrip – when this bit is set, the most-significant bit of receive characters is stripped,
leaving 7-bit characters. IStrip is applied after all other character processing, but
before special character processing.
Bit 6
LNext – this bit enables the LNext option
0 = All receive characters are processed for special character detection.
1 = The character following the LNext character is not processed for special charac-
ter matching or flow control.
This provides a mechanism to transfer flow control and special characters as normal
data, without invoking flow control action in the CD2231, and without generating
special interrupts. The LNext character is defined in the LNXT register, and when
processed, is always passed to the host CPU as normal data.
Bit 5
Flow control on error characters
0 = Characters received with an error are not processed for special character/flow
control matching.
Datasheet
INPCK
ParInt
0
0
0
Generated an exception interrupt
0
0
1
Translated to a NULL character
Ignore error; character passed on as good
0
1
0
data
0
1
1
Discard error character
1
0
0
Reserved
Translate to a sequence of FF NULL and the
1
0
1
error character and pass on as Good Data
1
1
0
Reserved
1
1
1
Reserved
Bit 4
Bit 3
0
0
Intel Hex Address: x’04
Motorola Hex Address: x’07
Bit 2
Bit 1
Bit 0
0
ONLCR
OCRNL
101