W3100A Datasheet, PDF (41/63 Pages) List of Unclassifed Manufacturers – i2Chip W3100A

pin, and the MCU bus I/F is activated by the External clock.
In Non-clocked mode, the internal functions of W3100A are executed by the clock granted to the clock pin,
and the MCU bus I/F is activated by /CS, /RD, /WR of MCU. As shown in the timing diagram, and unlike
Clocked mode and External clocked mode, a timing condition exists between /CS, /RD, and /WR.
I²C I/F mode is used when an MCU connected to W3100A supports I²C I/F but does not support bus I/F.
The basic frequency to be used for I²C is activated by the clock granted to the clock pin and both 100KHz
mode and 400KHz mode are supported.
2. Direct Bus I/F Mode.
MCU
/CS
/WR
/RD
/INT
D[7:0]
A[14:0]
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/CS
RX_CLK
/WR _RXDV/CRS
/RD RXD[3:0]
/INT
D[7:0]
A[14:0]
TX_CLK
TXE
TXD[3:0]
COL
/LINK
/FDPLX
CLOCK
Ethernet
PHY
RXC TX±
CRS RX±
RXD[3:0]
TXC
TXE
TXD[3:0]
COL
/LINK
/FDPLX
CLOCK
Trans-
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RJ-45
As illustrated in the above diagram, Direct Bus I/F mode uses a 15-bit address line and 8-bit data line, /CS,
/RD, /WR, /INT, which is identical to the I/F of the existing W3100A.
Since the access timing changes from Clocked mode (page 50) to External clocked mode (page 52) and to
Non-clocked mode (page 54), the MCU bus access timing needs to be considered.
3. Indirect Bus I/F Mode.
Indirect Bus I/F mode uses a 2-bit address line and 8-bit data line, /CS, /RD, /WR, and /INT.
Of the address lines, A[14:4] is grounded as ‘0’ and A[3:2] is pulled up (4.7 kΩ) to ‘1’.
MCU
/CS
/WR
/RD
/INT
D[7:0]
A[1:0]
VCC
4.7 kΩ
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/CS
RX_CLK
/WR _RXDV/CRS
/RD RXD[3:0]
/INT
D[7:0]
A[1:0]
TX_CLK
TXE
TXD[3:0]
COL
A[14:4]
/LINK
/FDPLX
A[3:2] ^CLOCK
Ethernet
PHY
RXC TX±
CRS RX±
RXD[3:0]
TXC
TXE
TXD[3:0]
COL
/LINK
/FDPLX
CLOCK
Trans-
formerG
RJ-45
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