Advantech RISC Module SOM-A2552 User Manual
Page 27
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User’s Manual for Advantech SOM-A2552 series module V1.00
27
B19 BUF_DQM0
O
SDRAM DQM for data byte 0.
Connect to the data output mask
enables (DQM) for SDRAM.
No pulling
A19 BUF_DQM2
O
SDRAM DQM for data byte 2.
Connect to the data output mask
enables (DQM) for SDRAM.
No pulling
B20 BUF_DQM3
O
SDRAM DQM for data byte 3.
Connect to the data output mask
enables (DQM) for SDRAM.
No pulling
A20 nBUF_PWAIT
I
PCMCIA wait. (input) Driven low by
the PCMCIA card to extend the
length of the transfers to/from the
PXA255 processor.
Pull high
with
100Kohm
B21
BUF_SDCLK
1
O
SDRAM Clock 1. Connect SDCLK
[1] to the clock pins of SDRAM in
bank pairs 0/1. They are driven by
either the internal memory controller
clock, or the internal memory
controller clock divided by 2. At
reset, all clock pins are free running
at the divide by 2 clock speed and
may be turned off via free running
control register bits in the memory
controller. The memory controller
also provides control register bits for
clock division and deassertion of
each SDCLK pin. SDCLK[2:1]
control register assertion bits are
always deasserted upon reset.
No pulling
A21
BUF_SDCKE
1
O
SDRAM and/or Synchronous Static
Memory clock enable. Connect to
the clock enable pins of SDRAM. It is
deasserted during sleep.
BUF_SDCKE1 is always deasserted
upon reset. The memory controller
provides control register bits for
deassertion.
No pulling
(For
SOM-255F
is
BUF_SDC
KE1)
B22 GND
P
Ground
-
A22 ADDR0
O
SoC PXA255 system address 0
No pulling
B23 ADDR1
O
SoC PXA255 system address 1
No pulling
A23 ADDR2
O
SoC PXA255 system address 2
No pulling
B24 ADDR3
O
SoC PXA255 system address 3
No pulling
A24 ADDR4
O
SoC PXA255 system address 4
No pulling
B25 ADDR5
O
SoC PXA255 system address 5
No pulling
A25 ADDR6
O
SoC PXA255 system address 6
No pulling
B26 ADDR7
O
SoC PXA255 system address 7
No pulling
A26 ADDR16
O
SoC PXA255 system address 16
No pulling
B27 ADDR17
O
SoC PXA255 system address 17
No pulling
A27 ADDR18
O
SoC PXA255 system address 18
No pulling