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AR-B1047 User’s Guide

4-1

4. HOW TO USE THE MEMORY BANKS

This section provides the information about how to access the memory on the AR-B1047 without using the AR-

B1047 SSD BIOS. The AR-B1047 hardware cut every 8K bytes of memory into a memory bank. To access the

data in memory, you have to assign the chip number and the bank number. On every chip, the memory bank

number starts from the number zero. The last memory bank number depends on the size of the memory chip used

on the AR-B1047. For example, if you use the 256K bytes memory chip, the bank number on every chip would be

in the range of 0 to 31. The chip number and the bank number are determined by the bank selected register and

the chip selected register on the AR-B1047.

The I/O address of these registers is determined by SW1-1 of SW1. The memory address of the memory bank is

located on the range selected by SW1-2 and SW1-7 of the SW1. Please refer to the how to select the I/O port

address and the memory address of the memory bank.

The I/O port address of the bank select register is base port+0 and the I/O port address of the chip select register

is base port + 2. The following is the format of the bank select register and chip select register.

Bank Select

Base+0 WPE A6 A5 A4 A3 A2 A1 A0

Chip Select

Base+2 0 0 0 0 0 CS2 CS1 CS0

Table 4-1 The Format of the Memory Bank

Where:

WPE

Write protect enable bit (refer to section “Using the Write

Protect Function” for details)

A6 –

––

– A0

Bank select bits, A0 is the LSB.

CS2 –

––

– CS0

Chip select bits of MEM1 to MEM8, CS0 is the LSB.

For different types of memory, A0 to A6 have different explanations. These bits are used to select the bank

number of specific memory located by CS0 to CS2.

Memory A6 A5 A4 A3 A2 A1 A0

64KB EPROM/FLASH 0 0 1 0 BS2 BS1 BS0

128KB EPROM/FLASH 0 0 1 BS3 BS2 BS1 BS0

256KB EPROM/FLASH 0 BS4 1 BS3 BS2 BS1 BS0

512KB EPROM/FLASH 0 BS4 BS5 BS3 BS2 BS1 BS0

1MB EPROM BS6 BS4 BS5 BS3 BS2 BS1 BS0

128KB SRAM 0 1 0 BS3 BS2 BS1 BS0

512KB SRAM 0 BS5 BS4 BS3 BS2 BS1 BS0

Table 4-2 The Different Type Memory Explanation

NOTE: BS0 to BS6 are the memory bank select bits. For example, 128KB memory has sixteen 8K-byte banks, so 4bits

(BS0 to BS3) are needed.

Example : Select the 10

bank of the MEM4 on the AR-B1047. The AR-B1047 is using 27C020 (256K X 8), and the

base port is &H224.

100 base_port=&H224

110 OUT base_port+0,&H19

120 OUT base_port+2,&H03

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 34

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