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
Table 1. Pin Descriptions (Sheet 1 of 3)
Pin
Symbol
Type
Number
CS*
1
AS*
14
I/O (TS)
DS*
15
I/O (TS)
R/W*
13
I/O (TS)
DTACK*
16
I/O (OD)
SIZ[0–1]
3, 4
I/O (TS)
IACKIN*
17
IACKOUT*
19
IREQ*[1–3]
21, 23, 24
I/O (OD)
BR*
7
OD
BGIN*
9
BGOUT*
10
Datasheet
CHIP SELECT*: When low, the CD2231 registers can be read or written by the
I
host processor.
ADDRESS STROBE*: When the CD2231 is a bus master, this pin is an output
which indicates that R/W*, A[0–7], and the externally latched A[8–31] are valid.
DATA STROBE*: When the CD2231 is not a bus master, this is an input used to
strobe data into registers during write cycles and enable data onto the bus
during read cycles. When the CD2231 is a bus master, DS* is an output used to
control data transfer to and from system memory.
READ/WRITE*: When the CD2231 is not a bus master, this pin is an input
which determines if a read or write operation is required when the CS* and DS*
signals are active. When the CD2231 is a bus master, R/W* is an output and
indicates whether a read from or a write to system memory is being performed.
DATA TRANSFER ACKNOWLEDGE*: When the CD2231 is not a bus master,
this is an output and indicates to the host when a read or write to the CD2231 is
complete. When BR* is driven low by the CD2231, DTACK* is an input which
indicates that the system bus is no longer in use. When the CD2231 is a bus
master, DTACK* is an input which indicates when system memory read and
write cycles are complete.
SIZE [0–1]: When not the active bus master, these are inputs that determine
the size of the operand being read or written by the host.
SIZ[1] SIZ[0]
0
1
Byte
1
0
16 Bit
0
0
32 Bit
1
1
3 Bytes
When the CD2231 is a bus master, this is an output determining the size of the
operand being transferred to or from system memory.
SIZ[1] SIZ[0]
0
1
Byte
1
0
16 Bit
See BYTESWAP description.
The CD2231 drives DTACK* even though the device does not respond to
such byte alignment.
INTERRUPT ACKNOWLEDGE IN*: This input, qualified with DS* and A[0–6],
I
acknowledges CD2231 interrupts.
INTERRUPT ACKNOWLEDGE OUT*: This output is driven low during interrupt
O
acknowledge cycles for which no internal interrupt is valid.
INTERRUPT REQUEST* [1–3]: These outputs signal that the CD2231 has a
valid interrupt for modem-lead activity (IREQ*[1]), transmit activity (IREQ*[2]), or
receive activity (IREQ*[3]).
BUS REQUEST*: This output is used to signal to the (open drain) host
processor or bus arbiter that bus mastership is required by the CD2231.
BUS GRANT IN*: This input indicates that the bus is available after the current
I
bus master relinquishes the bus.
BUS GRANT OUT*: This output is asserted when BGIN* is low and no internal
Bus Request has been made. A daisy-chain scheme of bus arbitration can be
O
formed by connecting BGOUT* to BGIN* of the next device in the chain. If a
priority scheme is preferred, bus requests must be prioritized externally and bus
grant routed to the BGIN* of the appropriate device.
Description
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