Memory Module - Nokia RH-9 Series Ccs Technical Documentation

CCS Technical Documentation

Memory Module

The RH-9 baseband memory module consists of 64-Mbit (8MB) external burst type flash
memory and 8Mbit internal and 4Mbit external SRAM. Only the external SRAM will be
covered here.
Memory Interface
The SRAM memory module is supplied by Samsung. The interface to the external SRAM is
asynchronous and consists of A818:09 address bus, I/O88:19 databus and 4 control sig-
nals (OE#, WE#, CS1# and CS"#).
Functional description
The functional description can be seen in 1) X means don't care (Must be in low or high
state)
CS # CS
1 2
1)
H X
1)
X L
L H
L H
L H
Signal description
Symbol Type
A18 - A0 I
I/O8 – I/O1 I/O
CS # I
1
CS I
2
OE# I
WE# I
Issue 1 11/02
Table 31: Functional description
OE# WE#
1) 1)
X X
1) 1)
X X
H H
L H
1)
X L
Table 32: Signal description
Address Inputs : for memory addresses
Data Input/Outputs: Data is output when OE# is low.
Chip Enable: CS # - low activates internal control logic. CS
1
device, places it in standby state and set outputs at high Z.
Chip Enable: CS - high activates internal control logic. CS
2
device, places it in standby state and set outputs at high Z.
Output Enable: When low, Activates the device's outputs through the data buffers
during a read cycle. When high, ouputs are disabled and placed in high
impedance state.
Write Enable: When low, activates the databus to be input. Address and data are
latched either on rising edge of WE# or CS
ãNokia Corporation
I/O Mode
High-Z Deselected
High-Z Deselected
High-Z Output disabled
Dout Read
Din Write
Name and Function
# or falling edge of CS
1
RH-9
System Module & UI
Power
Standby
Standby
Active
Active
Active
# high deselects the
1
low deselects the
2
.
2
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