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10006757-02 PmPPC7448 User’s Manual
4-1
Section 4
On-Card Memory Configuration
The PmPPC7448 includes the following memory devices:
• Up to 64 megabytes of Flash memory
• Synchronous DRAM (SDRAM) configurations up to 2 gigabytes
• Eight kilobytes of non-volatile memory
BOOT MEMORY CONFIGURATION
The PmPPC7448 boot default is the on-board Flash which occupies the physical address
space beginning at E800,0000
16
. Selecting jumper JP2 on the optional Development Mez-
zanine Card (DMC) allows the 8-bit ROM socket as the boot device (see “DMC Jumpers
(JP1)” on page 10-9). Read bit 3 of Board Configuration register 1 at F820,A000
16
(see Reg-
ister Map 7-11
) for the boot device selection.
Table 4-1: Memory Configuration Jumper
The MV64460 controls the access time for ROM. The default power-up timing allows
boards of any speed to work with ROMs that have access times faster than 150 nanosec-
onds. We strongly suggest that you use the default timing because of the inherent risks of
optimizing timing for a specific configuration.
USER FLASH
This configuration supports one bank of Flash memory. The PmPPC7448 circuit board
accommodates two Intel StrataFlash
™
devices (each 16 bits wide), allowing for as much as
64 megabytes of 32-bit wide user Flash at location E800,0000
16
. One megabyte at the base
of Flash is reserved for the monitor. The following table shows the configuration options.
Table 4-2: Flash Memory Configurations
The Flash devices interface to the most significant data bits of the PowerPC data bus. For
example, if the data path is 64 bits wide, the PowerPC data bus is declared as D[0:63],
where D0 is the most significant bit and D63 is the least significant bit. For a 32-bit data
path, the Flash devices interface to D[0:31]. For a 16-bit path, the data bus is D[0:15].
Jumper: Function: Options: Default Configuration:
JP2 Selects monitor
boot device
JP2 out, User Flash
JP2 in, DMC ROM socket
JP2 out, User Flash
Device
Density:
Data Path
Width: No. of Banks:
Total Memory
(Megabytes):
256 Mb 32 bits 1 64
128 Mb 32 bits 1 32