Memory Expansion Boards

 

 

Table E-2 Chip Select information block

 

 

 

Function

Address

Value

offset

 

 

 

 

 

Memory Type

0x0

0x0 = Reserved, 0x1 = Static NOR flash 2, 0x2 = Static NOR flash 1,

 

 

0x3 = Static SRAM, 0x4–0x80 = Reserved, 0x81 = Single Data Rate SDRAM,

 

 

0x82 = Sync Flash,

 

 

0x83–0xFE = Reserved,

 

 

0xFF = Not fitted.

 

 

 

Memory Width

0x01

Bits [3:0] indicate the chip-select width:

 

 

0 = byte wide, 1 = 16-bit wide, 2 = 32-bit wide, 3 = Reserved.

 

 

Bits [7:4] indicate the device memory width:

 

 

0 = byte wide, 1 = 16-bit wide, 2 = 32-bit wide, 3 = Reserved.

 

 

 

Access time

0x02

Two bytes containing the access time (tach) decoded as a binary number of 100ps.

 

 

Location 2 contains the LSB and location 3 contains the MSB. For example, a flash

 

 

device with 120ns access is 1200 * 0.1ns. The decimal value is 1200 and the hex value

 

 

is 0x04B0, therefore location 2 contains 0xb0 and location 3 contains 0x04.

 

 

 

Size

0x04

Four bytes containing the size of the memory in bytes location 4 is the LSB and location

 

 

7 is MSB.

 

 

 

Reserved

0x08–0x0F

Eight bytes reserved for future expansion

 

 

 

Device string

0x10–0x2F

Null terminated string of up to 32 characters (31 characters + null character) containing

 

 

the manufacturer name and part number.

 

 

 

The base address of the information block is determined by the device chip select used.

ARM DUI 0224I

Copyright © 2003-2010 ARM Limited. All rights reserved.

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ARM ARM DUI 0224I manual Table E-2 Chip Select information block, Function Address Value Offset