PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATMTraffic Management Device
Released
Datasheet
69
4.3.7
Receive Cell Buffer DRAMs
Table 14. Receive Cell Buffer RAM Interface Signals (49 Pins)
NOTE: DQM (I/O mask enables) pins to the SGRAM need to be tied to logic 0.
Signal Name
Ball
Type
Drive/
Input Level
Slew
Rate
Description
RX_DRAM_ADD(8:0)
J26, F28, K25, G28,
H26, J27, K26, J25,
K28
Out
5 ma
Mod
RX DRAM Address Bits 8 to 0
are
part of the 9-bit SRAM address bus.
Note that TX_DRAM_ADD(8)
must be connected to the AutoPre-
charge pin.If DRAM_TYPE = 1
(refer to
“RX_DRAM_TYPE” on
page 104
) then connect
RX_DRAM_ADD(8) to the DRAM
autoprecharge pin, which should be
bit 10 of the DRAM address bus
RX_DRAM_DATA(31:0)
B23, E21, D22, B24,
B25, C23, E22, C24,
D23, B26, C25, D24,
B27, E24, C26, E23,
D25, C27, G25, B28,
E26, C28, E27, D27,
D28, F25, E28, G26,
F26, F29, F27, G27
Bidir
5 ma/CMOS
Mod
Receive DRAM Data Bits 31 to 0
are part of the 32-bit SRAM data
bus.
RX_DRAM_CLK
J28
Out
8 ma
Fast
Receive DRAM Clock
provides the
clock to the SDRAM.This signal
should be terminated with a series
resistor before connecting to the
RAM modules
DRAM_CKE
L25
Out
5 ma
Mod
DRAM Clock Enable
provides a
clock enable signal for RX_DRAM
and TX_DRAM
/RX_DRAM_CS(1:0)
H25, H28
Out
5 ma
Mod
Receive DRAM Chip Select Bits 1 to
0
enable the SDRAMs. If
DRAM_TYPE = 1 (refer to
“RX_DRAM_TYPE” on page 104
),
these are RX_DRAM_ADD(9:8).
RX_DRAM_BA
N25
Out
5 ma
Mod
Receive DRAM Bank Address
defines the bank to which the opera-
tion is addressed.
/RX_DRAM_RAS
K27
Out
5 ma
Mod
Receive DRAM Row Address Strobe
is an active low signal that writes in
the row address.
/RX_DRAM_CAS
M25
Out
5 ma
Mod
Receive DRAM Column Address
Strobe
is an active low signal that
writes in the column address.
/RX_DRAM_WE
H27
Out
5 ma
Mod
Receive DRAM Write Enable
is an
active low signal that enables a
write into the synchronous DRAM.