Register Page Pointer (Pp) - Samsung S3C84I8 User Manual

S3C84I8/F84I8/C84I9/F84I9

REGISTER PAGE POINTER (PP)

The S3C8-series architecture supports the logical expansion of the physical 512-byte internal register file (using
an 8-bit data bus) into as many as 2 separately addressable register pages. Page addressing is controlled by the
register page pointer (PP, DFH). In the S3C84I8/F84I8/C84I9/F84I9 microcontroller, a paged register file
expansion is implemented for 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.
MSB
Destination register page selection bits:
0000
0001
0002
NOTE:
Register Page Pointer (PP)
DFH ,Set 1, R/W
.7 .6 .5
Destination: Page 0
Destination: Page 1
Destination: Page 2
In the S3C84I9/F84I9 microcontroller, page 0,1,2 are implemented.
A hardware reset operation writes the 4-bit destination and source values shown
above to the register page pointer(00H). These values should be modified to
other pages
Figure 2-5. Register Page Pointer (PP)
.4 .3 .2 .1
Source register page selection bits:
0000 Source: Page 0
0001 Source: Page 1
0002 Source: Page 2
ADDRESS SPACES
.0 LSB
2-7