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Hardware Description
Copyright © ARM Limited 2000. All rights reserved.
3-23
3.6
Memory subsystem
The P1100 uses low power EDO DRAM for its main memory and screen buffer, and
flash memory for storing boot images and other non-volatile data. The amount of
memory fitted is a build-time option.
3.6.1
Flash memory
Non-volatile storage is provided by up to eight Intel 5V StrataFlash devices. The CPU
card is fitted with 64Mbit devices organized as 4M x 16. These are fitted in pairs, with
each pair providing a 16MB area of memory with a 32-bit data path. The P1100
provides support for up to four pairs (eight devices) providing 64MB of flash memory,
although only the 32MB product variant is currently available. The flash memory is
decoded within the region decoded by chip-select 0 from the SA-1100. This provides a
single contiguous 64MB region for the flash memory (see Flash chip-select control on
page 3-18).
The parts used are Intel G28F640J5-150 parts in a 56 ball microBGA package.
Note
The 16-bit ROM size SA-1100 option is not supported by the P1100.
Flash hardware interface
The hardware interface to the SA-1100 is as follows:
•
buffered address and data buses
•
a +5V level translated version of the system reset is connected to the flash
nRP
pins.
•
data and address buffers controlled by the XCR3128 PLD (see Buffer control on
page 3-19)
•
+5V level translated versions of the chip selects decoded by the XCR3128 PLD
(see Flash chip-select control on page 3-18).
•
buffered versions of the
MEM_nOE
and
MEM_nWE
from the SA-1100
A 74HCT244 is used to translate the control signals to +5V signal levels. This decreases
the power consumption by the flash devices.
Figure 3-9 on page 3-24 shows the architecture of the Flash memory. To aid clarity the
diagram does not show the data and address buffers, or the output enables and write
enable signals.
Содержание Prospector P1100
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Страница 4: ...iv Copyright ARM Limited 2000 All rights reserved ARM DUI 0122A ...
Страница 86: ...Hardware Description 3 54 Copyright ARM Limited 2000 All rights reserved ARM DUI 0122A ...
Страница 140: ...Connector reference A 18 Copyright ARM Limited 2000 All rights reserved ARM DUI 0122A ...