Personal Computer User Manual

4-6 Computer Group Literature Center Web Site

Functional Description

Application Note: For Am29DL322C or Am29DL323C, 32Megabit

(4M x 8-Bit/2M x 16-bit) CMOS 3.0 Volt-only Flash Memory.

The Write Protect function provides a hardware method of protecting

certain boot sectors. If the system asserts V IL (low signal) on the

WP#/ACC pin, the device disables the program and erase capability,

independently of whether those sectors were protected or unprotected

using the method described in the Sector/Sector Block Protection and

Unprotection of the AMD datasheet. The two outermost 8Kbyte boot

sectors are the two sectors containing the lowest addresses in a bottom-

boot-configured device, or the two sectors containing the highest addresses

in a top-boot-configured device.

The aforementioned Motorola implemented device (at the time of this

printing is the only Motorola qualified Flash device used on this product)

is a top-boot device, and as such, the write protected area is in the upper

16KB of each device. And, since Motorola is using 4 devices for the

soldered Flash bank, the write protected region corresponds to the upper

64KB of the soldered Flash memory map. Thus the address range of

$F4FF 0000 to F4FF FFFF is the write protected region when the J16

header is jumpered across pins 2 and 3.

If PPCBug tries to write to those write-protected address areas when

pins 2-3 on J16 are set, the command will simply not finish (i.e., erase

sector function stops at $F4FF 0000).

ECC SDRAM Memory

The MVME5100’s on-board memory and optional memory mezzanines

allow for a variety of memory size options. Memory size can be 64 or

512MB for a total of 1GB on-board and mezzanine ECC memory. The

memory is controlled by the hardware which provides single-bit error

correction and double-bit error detection (ECC is calculated over 72-bits).

Either 1 or 2 mezzanines can be installed. Each mezzanine will add 1 bank

of SDRAM memory of 256MB. A total of 512MB of mezzanine memory

can be added. Refer to Appendix D, RAM500 Memory Expansion Module

for more information.