Samsung C8278X ユーザーズマニュアル

The S3C8-series architecture supports the logical expansion of the physical 256-byte internal register file (using 
an 8-bit data bus) into as many as 16 separately addressable register pages. Page addressing is controlled by 
the register page pointer (PP, DFH). In the S3C8275X/C8278X/C8274X microcontroller, a paged register file 
expansion is implemented for LCD data registers, and the register page pointer must be changed to address 
other pages. 

After a reset, the page pointer's source value (lower nibble) and the destination value (upper nibble) are always 
"0000", automatically selecting page 0 as the source and destination page for register addressing.  

Register Page Pointer (PP)

DFH, Set 1, R/W

LSB

MSB

.7

.6

.5

.4

.3

.2

.1

.0

Destination register page selection bits:

NOTES:
1.    In the S3C8275X microcontroller, the internal register file is configured as three pages (Pages 0-2).
       The pages 0-1 are used for general purpose register file, and page 2 is used for LCD data register or
       general purpose register.
2.    In the S3C8278X/C8274X microcontroller, the internal register file is configured as two pages (Pages 0, 2).
       The page 0 is used for general purpose register file, and page 2 is used for LCD data register or general
       purpose register.
3.    A hardware reset operation writes the 4-bit destination and source values shown above to the register page
       pointer. These values should be modified to address other pages.

0000

Destination: Page 0

0001

Destination: Page 1 (Not used for the S3C8278X/C8274X)

0010

Destination: Page 2

others

Not used for the S3C8275X/C8278X/C8274X

Source register page selection bits:

0000

Source: Page 0

0001

Source: Page 1 (Not used for the S3C8278X/C8274X)

0010

Source: Page 2

others

Not used for the S3C8275X/C8278X/C8274X