CD2231 Intel Corporation, CD2231 Datasheet - Page 128

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CD2231

Manufacturer Part Number
CD2231
Description
CD2231 Intelligent Two-channel Lan And Wan Communications Controller
Manufacturer
Intel Corporation
Datasheet
CD2231 — Intelligent Two-Channel LAN and WAN Communications Controller
128
Register Name: RISRl
Register Description: Receive Interrupt Status — Low
Default Value: x’00
Access: Byte Read only
Register Name: RISRl
Register Description: Receive Interrupt Status — Low
Default Value: x’00
Access: Byte Read only
Timeout
Bit 7
Bit 7
0
RISRl — Asynchronous Mode
If RxData in IER is set, these interrupts are enabled.
Bit 7
Bits 6:4
Bit 3
Bit 2
Bit 1
Bit 0
RISRl — Async-HDLC / PPP / MNP 4 Mode
If RxData in IER is set, these interrupts are enabled.
Bit 7
SCdet2
Bit 6
Bit 6
EOF
Timeout – indicates that the receive FIFO is empty, and no data has been received
within the receive timeout period. There is no data character associated with this sta-
tus, and no other status bits are valid if the Time-Out bit is set.
Special character detect
Overrun error – indicates that new data has arrived, but the CD2231 FIFO or holding
registers are full. The new data is lost and the overrun indication is flagged on the
last character received before the overrun occurred.
Parity error – indicates that a parity error has occurred.
Framing error – indicates that a bad Stop bit is detected.
Break – indicates that a break is detected.
Reserved – always returns ‘0’ when read.
SCdet1
RxAbt
Bit 5
Bit 5
SCdet[2:0]
000
001
010
011
100
111
SCdet0
CRC
Bit 4
Status
None detected
Special Character 1 matched
Special Character 2 matched
Special Character 3 matched (only if ESCDE is enabled in COR3)
Special Character 4 matched (only if ESCDE is enabled in COR3)
Character is within the inclusive range of the characters in the Special
Character Range low and high registers (only if RngDE is enabled in
COR3). Special character match can be enabled for error characters by
COR7.
Bit 4
Bit 3
Bit 3
OE
OE
Bit 2
Bit 2
PE
FE
Motorola Hex Address: x’89
Motorola Hex Address: x’89
Bit 1
Bit 1
FE
0
Intel Hex Address: x’8A
Intel Hex Address: x’8A
Datasheet
Break
Break
Bit 0
Bit 0

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