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IDT RC32438 Device Overview
Pin Description
79RC32438 User Reference Manual
1 - 12
November 4, 2002
Notes
CSN[5:0]
O
Chip Selects.
These signals are used to select an external device on the mem-
ory and peripheral bus.
MADDR[21:0]
O
Address Bus.
22-bit memory and peripheral bus address bus.
MADDRP[25:22] are available as GPIO alternate functions
MDATA[15:0]
I/O
Data Bus.
16-bit memory and peripheral data bus. During a cold reset, these
pins function as inputs that are used to load the boot configuration vector.
OEN
O
Output Enable.
This signal is asserted when data should be driven on by an
external device on the memory and peripheral bus.
RWN
O
Read Write.
This signal indicates if the transaction on the memory and periph-
eral bus is a read transaction or a write transaction. A high level indicates a read
from an external device. A low level indicates a write to an external device.
WAITACKN
I
Wait or Transfer Acknowledge.
When configured as wait, this signal is
asserted during a memory and peripheral bus transaction to extend the bus
cycle. When configured as a transfer acknowledge, this signal is asserted during
a transaction to signal the completion of the transaction.
DDR Bus
DDRADDR[13:0]
O
DDR Address Bus.
13-bit multiplexed DDR bus address bus. This bus is used
to transfer the addresses to the DDRs.
DDRBA[1:0]
O
DDR Bank Address.
These signals are used to transfer the bank address to the
DDRs.
DDRCASN
O
DDR Column Address Strobe.
DDR column address strobe which is asserted
during DDR transactions.
DDRCKE
O
DDR Clock Enable.
DDR clock enable which is asserted during normal DDR
operation. This signal is negated during following a cold reset or during a power
down operation.
DDRCKN[1:0]
I/O
DDR Negative DDR clock.
These signals are the negative clock of the differen-
tial DDR clock pair. Two copies of this output are provided to reduce signal load-
ing.
DDRCKP[1:0]
I/O
DDR Positive DDR clock.
These signals are the positive clock of the differen-
tial DDR clock pair. Two copies of this output are provided to reduce signal load-
ing.
DDRCSN[1:0]
O
DDR Chip Selects.
These active low signals are used to select DDR device(s)
on the DDR bus.
DDRDATA[31:0]
I/O
DDR Data Bus.
32-bit DDR data bus used to transfer data between the
RC32438 and the DDR(s). Data is transferred on both edges of the clock.
DDRDM[7:0]
I/O
DDR Data Write Enables.
Byte data write enables are used to enable specific
byte lanes during DDR writes.
DDRDM[0] corresponds to DDRDATA[7:0]
DDRDM[1] corresponds to DDRDATA[15:8]
DDRDM[2] corresponds to DDRDATA[23:16]
DDRDM[3] corresponds to DDRDATA[31:24]
DDRDM[4] corresponds to DDRDATA[39:32]
DDRDM[5] corresponds to DDRDATA[47:40]
DDRDM[6] corresponds to DDRDATA[55:48]
DDRDM[7] corresponds to DDRDATA[54:56]
(Refer to the DDR Data Bus Multiplexing section in Chapter 7.)
Signal
Type
Name/Description
Table 1.1 Pin Description (Part 2 of 9)