Freescale Semiconductor ColdFire MCF5274, User Manual

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1-6 M5275EVB User’s Manual
System Memory
1.2 System Memory
The following diagram shows the external memory implementation on the M5275EVB.
Figure 1-3. External Memory Scheme
NOTE
The external bus interface signals to the external ASRAM and
Flash are buffered. This is in order to separate the 2.5V bus to
the DDR from the 3.3V bus to the Flash and ASRAM.
The external bus signals to the expansion connectors are
buffered to 3.3V to provide a 3.3V interface to the user.
1.2.1 External Flash
The EVB is fitted with a single 1M x 16 page-mode Flash memory (U11) giving a total
memory space of 2 MBytes. Alternatively a footprint is available for the EVB user to
upgrade this device to a 2M x 16 page-mode Flash memory (U12), doubling the memory
size to 4 MBytes. Either U11 OR U12 should be fitted on the board - both devices cannot
be populated at the same time. Refer to the specific device data sheet and sample software
provided for information on configuring the Flash memory.
Users should note that the debug monitor firmware is installed on this flash device.
Development tools or user application programs may erase or corrupt the debug monitor. If
the debug monitor becomes corrupted and it’s operation is desired, the firmware must be
reprogrammed into the flash by using a development tool through the BDM port. Users
Expansion
Connectors
DDR SDRAM
(16MBytes)
ASRAM
(
1MByte
)
Flash
(1M x 16)
or
(2M x 16)
Buffers
Data
Address
Control
MCF5275