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
8.5.2.5
Receive FIFO Output Count (RFOC)
Register Name: RFOC
Register Description: Receive FIFO Output Count
Default Value: x’00
Access: Byte Read only
Bit 7
Bit 6
Bit 5
0
0
0
Bits 7:5
Reserved – always returns ‘0’ when read.
Bits 4:0
Receive data count
If the receive channel is interrupt driven, a non-zero value in this bit field is the num-
ber of data characters available for transfer within the current receive interrupt.
8.5.2.6
Receive Data Register (RDR)
Register Name: RDR
Register Description: Receive Data
Default Value: x’00
Access: Byte Read only
Bit 7
Bit 6
Bit 5
D7
D6
D5
This Virtual register accesses the receive data FIFO of a channel interrupting for receive data
transfer. This register address is used for all channels to transfer receive FIFO data to the host, if
programmed in Interrupt Transfer mode. Data must be read as bytes, and follows the rules listed in
Section 8.3
for the positioning of valid data on the bus. If the BYTESWAP pin is high, data is valid
on A/D[7:0], if BYTESWAP is low, data is valid on A/D[15:8]. This is true because the RDR is on
an even address.
8.5.2.7
Receive End of Interrupt Register (REOIR)
REOIR — Asynchronous and HDLC Modes
Register Name: REOIR
Register Description: Receive End of Interrupt
Default Value: x’00
Access: Byte Write Only
Bit 7
Bit 6
Bit 5
TermBuff
DiscExc
SetTm2
The CD2231 interprets values written to this register at the completion of all receive interrupts.
Bit 7
Terminate current DMA buffer
If this bit is set, the current receive buffer is terminated and data transfer is switched
Datasheet
Bit 4
Bit 3
Bit 2
RxCt4
RxCt3
RxCt2
Bit 4
Bit 3
Bit 2
D4
D3
D2
Bit 4
Bit 3
Bit 2
SetTm1
NoTrans
Gap2
Intel Hex Address: x’33
Motorola Hex Address: x’30
Bit 1
Bit 0
RxCt1
RxCt0
Intel Hex Address: x’F8
Motorola Hex Address: x’F8
Bit 1
Bit 0
D1
D0
Intel Hex Address: x’87
Motorola Hex Address: x’84
Bit 1
Bit 0
Gap1
Gap0
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