MVME5100 Single Board Computer Programmer's Reference Guide

3
System Memory Controller (SMC)
Table 3-19. Programming SDRAM SIZ Bits
Total Number of
Locations within
the Block (L) 1
Primary
Device Width 2
Block Size 3
Value to be
programmed into
the Block’s
ram_x_siz bits 4
4M 16 32MB %0001
8M 8 64MB %0010
8M 16 64MB %0011
16M 4 128MB %0100
16M 8 128MB %0101
16M 16 128MB %0110
32M 4 256MB %0111
32M 8 256MB %1000
64M 4 512MB %1001
Notes 1. Total Number of block Locations (L) is 2R x 2C x 4 where
R is the value in SPD byte 3 and C is the value in SPD byte 4.
2. Primary Device Width is from SPD byte 13.
3. Block Size is the total number of block locations (L) x 8
bytes.
4. ram_x_siz refers to ram_a_siz, ram_b_siz, ram_c_siz, etc.
(Refer to the sections titled SDRAM Enable and Size Register
(Blocks A,B,C,D) and SDRAM Enable and Size Register (Blocks
E,F,G,H) for more information.
6. Make sure the software is no longer using SDRAM, and disable the
block that was being used.
7. Wait for at least one SDRAM refresh to complete. A simple way to
do this is to wait for the 32-bit counter to increment at least 100
times. (Refer to the section titled “32-Bit Counter” for more
information). Note that the refdis control bit must not be set in the
ECC Control Register.
3-82 Computer Group Literature Center Web Site