IDE OUTPUT ENABLES
output enables treat all IDE transfers as 16 bit
transfers.
Two IDE output Enables are available. The IDE
nIDE1_OE
IDE1 (1)
IDE1&IDE2 (3)
nIDE2_OE
IDE2 (2)
Option 1
Option 2
(Not used)
Note 1: The low and high byte transfer for IDE1 goes through external buffers controlled by IDE1_OE.
(Refer to Option 1)
Note 2: The low and high byte transfer for IDE2 goes through external buffers controlled by IDE2_OE.
(Refer to Option 1)
Note 3: The low and high byte transfers of IDE1 and IDE2 go through one set of external buffers
controlled by IDE1. (Refer to Option 2)
buffer that can be used for a BIOS Buffer. If the
BIOS buffer is not used, then nROMCS and
nROMDIR must be tied high so as not to
interfere with the boot ROM. This function
allows data transmission from the RD bus to the
SD bus or from the SD bus to the RD bus. The
direction of the transfer is controlled by
nROMDIR. The enable input, nROMCS, can be
used to disable the transfer and isolate the
buses.
HDCS0 and HDCS1 of IDE1 as General
Purpose Address Decoders
HDCS0 and HDCS1 of IDE1, initially configured
to support IDE drives, can be programmed as
general purpose address decoders. Refer to the
Configuration Register Section, Logical Device
1, CRF0 and CRF1.
BIOS BUFFER
The FDC37C93xFR contains one 245 type
nROMCS
nROMDIR
DESCRIPTION
RD[0:7] data to SD[0:7] bus
SD[0:7] data to RD[0:7]
Isolation
L
L
L
H
X
H
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SMSC [ SMSC CORPORATION ]
