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IDT RC32438 Device Overview
Pin Description
79RC32438 User Reference Manual
1 - 11
November 4, 2002
Notes
Pin Description
The following table lists the function of the pins provided on the RC32438. Some of the functions listed
may be multiplexed onto the same pin.
Miscellaneous
CLK
I
LVTTL
STI
EXTCLK
O
LVTTL
High Drive
COLDRSTN
I
LVTTL
STI
RSTN
I/O
LVTTL
Low Drive /
STI
pull-up
pull-up on board
1.
External pull-up required in most system applications. Some applications may require additional pull-ups not identified in this
table.
2.
Schmidt Trigger Input (STI)
3.
PCIMUINTN is an alternate function of GPIO[30]. When configured as an alternate function, this pin is tri-stated when not as-
serted (i.e., it acts as an open collector output).
Signal
Type
Name/Description
System
CLK
I
Master Clock.
This is the master clock input. The processor frequency is a mul-
tiple of this clock frequency. This clock is used as the system clock for all mem-
ory and peripheral bus operations.
EXTCLK
O
External Clock.
This clock is used for all memory and peripheral bus opera-
tions.
COLDRSTN
I
Cold Reset.
The assertion of this signal initiates a cold reset. This causes the
processor state to be initialized, boot configuration to be loaded, and the internal
PLL to lock onto the master clock (CLK).
RSTN
I/O
Reset.
The assertion of this bidirectional signal initiates a warm reset. This sig-
nal is asserted by the RC32438 during a warm reset.
Memory and Peripheral Bus
BDIRN
O
External Buffer Direction.
Memory and peripheral bus external data bus buffer
direction control. If the RC32438 memory and peripheral bus is connected to the
A side of a transceiver such as an IDT74FCT245, then this pin may be directly
connected to the direction control (e.g., BDIR) pin of the transceiver.
BGN
O
Bus Grant.
This signal is asserted by the RC32438 to indicate that the
RC32438 has relinquished ownership of the memory and peripheral bus.
BOEN
O
External Buffer Enable.
This signal provides an output enable control for an
external buffer on the memory and peripheral data bus.
BRN
I
Bus Request.
This signal is asserted by an external device to request owner-
ship of the memory and peripheral bus.
BWEN[1:0]
O
Byte Write Enables.
These signals are memory and peripheral bus by write
enable signals.
BWEN[0] corresponds to byte lane MDATA[7:0]
BWEN[1] corresponds to byte lane MDATA[15:8]
Table 1.1 Pin Description (Part 1 of 9)
Function
Pin Name
Type
Buffer
I/O Type
Internal
Resistor
Notes
1
Table 1 Pin Characteristics (Part 4 of 4)