Advantech RISC Module SOM-A2552 User Manual
Page 31
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User’s Manual for Advantech SOM-A2552 series module V1.00
31
memory block. About detail
description, please reference
“SOM-A255x series Memory and
Interrupt Map”.
B48 nBUF_CS5
O
Static chip selects. Chip selects to
static memory devices such as ROM
and Flash. Individually
programmable in the memory
configuration registers. nBUF_CS5
can be used with variable latency I/O
devices.
Advantech default uses the pin as
display chip chip select pin.
nBUF_CS4 pin is used for SM501 on
SOM-A2552 & SOM-A255F series. If
no special application, Advantech
strongly suggest user to open this
pin in CSB.
Pull high
with
100Kohm
A48 DMA_REQ1
I
Channel 1 DMA Request. Notifies
the DMA Controller that an external
device requires a DMA transaction. If
user wants to design a controller in
CSB with DMA mode, please check
with
first.
If use doesn’t want to use this pin as
DMA_REQ, use could use the pin as
GPIO. The pin connects to SoC
PXA255 GPIO19.
Pull low
with 1Kohm
B49 MBREQ
I
Memory Controller alternate bus
master request. Allows an external
device to request the system bus
from the Memory Controller. If user
wants to design a controller in CSB
with this pin function, please check
with
first.
If use doesn’t want to use this pin as
DMA_REQ, use could use the pin as
GPIO. The pin connects to SoC
PXA255 GPIO14.
Pull low
with 1Kohm
A49 DMA_ACK1
O
Channel 1 DMA acknowledge.
Notifies an external device that it has
been acknowledged the DMA
controller. If user wants to design a
controller in CSB with DMA mode,
please check with
first.
If use doesn’t want to use this pin as
DMA_ACK, use could use the pin as
GPIO. The pin connects to SoC
PXA255 GPIO22.
No pulling