Samsung C8274X Manuel D’Utilisation
ADDRESS SPACES
S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
2-8
REGISTER PAGE POINTER (PP)
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.
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.
"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.
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
Figure 2-5. Register Page Pointer (PP)