CHIP-SELECT UNIT

6.4.2.2LCS Active Range

The LCS starting address is fixed at zero in memory address space; its ending address is the pro- grammed block size minus one. Table 6.3 defines the acceptable values for the field (U17:10) in the LMCS register that determines the LCS block size and ending address.

Table 6.3 LCS Active Range

LMCS Field

Block Size

Ending Address

U17:10

(Kbytes)

 

 

 

 

00H

1

003FFH

 

 

 

01H

2

007FFH

 

 

 

03H

4

00FFFH

 

 

 

07H

8

01FFFH

 

 

 

0FH

16

03FFFH

 

 

 

1FH

32

07FFFH

 

 

 

3FH

64

0FFFFH

 

 

 

7FH

128

1FFFFH

 

 

 

FFH

256

3FFFFH

 

 

 

6.4.2.3MCS Active Range

The starting and ending addresses of the individual MCS chip-selects are determined by the base address programmed in the MMCS register and the block size programmed in the MPCS register (see Table 6-4 and Figure 6-10). The base address must be an integer multiple of the block size. Table 6-5 lists the allowable block sizes and base address limitations.

Table 6-4. MCS Active Range

 

 

Chip-

Active Range

 

 

 

 

 

 

Select

Start Address

Ending Address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Base

Base + (1/4 block size –1)

MCS0

 

 

 

 

 

 

 

 

 

Base + 1/4 block size

Base + (1/2 block size –1)

 

MCS1

 

 

 

 

 

 

 

 

 

Base + 1/2 block size

Base + (3/4 block size –1)

 

MCS2

 

 

 

 

 

 

 

 

 

Base + 3/4 block size

Base + (block size – 1)

 

MCS3

 

 

 

 

 

 

6-13

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Intel 80C188XL, 80C186XL user manual LCS Active Range, MCS Active Range, Lmcs Field Block Size Ending Address U1710