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3 basic functions and register setting – Toshiba H1 SERIES TLCS-900 User Manual

Page 82

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TMP92CM22

2007-02-16

92CM22-80

3.6.3

Basic Functions and Register Setting

In this section, setting of the block address area, the connecting memory and the

number of waits out of the memory controller’s functions are described.

(1) Block address area specification

The block address area is specified by two registers.
The memory start address register (MSAR) sets the start address of the block

address areas. The memory controller compares between the register value and the
address every bus cycles. The address bit which is masked by the memory address
mask register (MAMR) is not compared by the memory controller. The block address
area size is determined by setting the memory address mask register. The set value in
the register is compared with the block address area on the bus. If the compared result
is a match, the memory controller sets the chip select signal (

CS

) to “low”.

(i) Setting memory start address register

The MS23 to MS16 bits of the memory start address register respectively

correspond with addresses A23 to A16. The lower start address A15 to A0 are
always set to address 0000H.

Therefore the start address of the block address area are set to addresses

000000H to FF0000H every 64 Kbytes.

(ii) Setting memory address mask registers

The memory address mask register sets whether an address bit is compared or

not. Set the register to “0” to compare, or to “1” not to compare.

The address bit to be set is depended on the block address area.
Block address area 0: A20 to A8
Block address area 1: A21 to A8
Block address area 2 to 3: A22 to A15
The above-mentioned bits are always compared. The block address area size is

determined by the compared result.

The size to be set depending on the block address area is as follows.

Size (bytes)

CS area

256

512

32 K

64 K

128 K

256 K

512 K

1 M

2 M

4 M

8 M

CS0

CS1

CS2 to CS3

Note: After reset release, only the control register of the block address area 2 is valid. The control

register of the block address area 2 has bit. Setting bit to “0” sets the block

address area 2 to addresses 000000H to FFFFFFH. State of after reset release is set this.

Setting bit to “1” specifies the start address and the address area size as it is in the other

block address area.

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