Proprietary and Confidential to PMC-Sierra, Inc and for its Customers
’
Internal Use
Document ID: PMC-2010146, Issue 4
29
PM2329 ClassiPI Network Classification Processor Datasheet
Table 3
ERAM Interface Signals
Signal Name
EMCE*
Ball #
P24
Size
1
I/O
O
Description
Extended Memory Chip Enable (Active Low)
This signal when active selects the entire bank of
Extended Memory. Only the primary PM2329 device
drives this signal. The EMCE* signal from the primary
device should be tied to the the Chip Enable inputs of all
the E-RAMs (C-Word and all D-Words) in the E-RAM
array. The EMCE* signal of all secondary PM2329
devices should be left unconnected.
Extended Memory Output Enable (Active Low)
EMOE*
R25
1
O
Read enable to the entire bank of Extended Memory.
Only the primary PM2329 device drives this signal. The
EMOE* signal from the primary device should be tied to
the the Output Enable inputs of all the E-RAMs (C-Word
and all D-Words) in the E-RAM array. The EMOE* signal
of all secondary PM2329 devices should be left
unconnected.
Spare signals for future use
SPARE4
SPARE3
T24
M26
2
O
These signals are reserved for future use, in the current
device they can be left unconnected.
Current proposed assignment on future devices, subject
to change, is shown below. The current default output
state of the signals is shown in parentheses.
SPARE4: ECTL (1)
SPARE3: EMA[19] (0)
Extended Memory Address Bus
EMA[18:0]
Refer
to
section
2.3
tables
2.4-2.5
19
O
Address bus for the Extended Memory. Any of the
cascaded PM2329 devices can drive this bus.
Address lines EMA[16:0] are driven from the E-RAM
Address field whereas EMA[18:17] are driven from the
depth control field.
For EMA[16:0] signals, the number of address bits that
need to be connected to the external E-RAM device is a
function of the total number of E-Words required.
EMA[18:17] can be left unconnected if depth is 1. For
depth of 2, only EMA[17] needs to be connected. For
depth of 4, EMA[18:17] should be connected.
Extended Data Memory Data Bus
EDD[31:0]
Refer
to
section
2.3
tables
2.5-2.6
32
I/O
Data bus for the data memory assigned to each of the
PM2329 devices.