Panasonic F77G, MN101C77C user manual „Memory Area Control Register Areactr

Models: F77G MN101C77C

1 544
Download 544 pages 59.61 Kb
Page 69
Image 69

Chapter 2 CPU Basics

„Memory Area Control Register (AREACTR)

AREACTR

7

6

5

4

3

2

1

 

0

 

 

CS8EXT

CS7EXT

CS6EXT

CS5EXT

CS4EXT

CS3EXT

CS2EXT

CS1EXT

( At reset : 1 1 1 1 1 1 1 1 )

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CS1EXT

Set always to "0"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CS8 to 2EXT Internal memory / External memory selection

0

Internal

 

Don't care

1

External memory

Figure 2-3-3 Memory Area Control Register (AREACTR : x'03F03', R/W)

In CS0 area, MMOD pin selects internal ROM/external memory. In CS9 area, only external memory can be selected as internal memory is not available.

The MN101CF77 contains internal memory in CSI area. Therefore, set the CS1EXT flag of the memory area control register (AREACTR) to "0" . When CS1EXT flag is not set to "0", the data cannot be accessed to 112KB (x'04000' to x'1FFFF' ) of internal ROM space.

Bus Interface

II - 17

Page 69
Image 69
Panasonic F77G, MN101C77C „Memory Area Control Register Areactr, Memory Area Control Register Areactr x03F03, R/W