C508_01 Datasheet, PDF (35/267 Pages) Infineon Technologies AG – 8-Bit CMOS Microcontroller

C508
Memory Organization
3.5
Special Function Registers
With the exception of the program counter and the four general purpose register banks,
the registers reside in the special function register area. The special function register
area consists of two portions: the standard special function register area and the mapped
special function register area. One special function register of the C508 (PCON1) is
located in the mapped special function register area. To access the mapped special
function register area, bit RMAP in the special function register SYSCON must be set.
All other special function registers are located in the standard special function register
area which is accessed when RMAP is cleared (0).
Special Function Register SYSCON (Address B1_H)
Reset Value: XX10XX01_B
Bit No. MSB
7
B1_H
–
6
5
4
3
– EALE RMAP –
LSB
2
1
0
– XMAP1 XMAP0 SYSCON
The functions of the shaded bits are not described here.
Bit
RMAP
–
Function
Special Function Register Map bit
RMAP = 0: Access to the non-mapped (standard) special function
register area is enabled.
RMAP = 1: Access to the mapped special function register area is
enabled.
Reserved bits for future use. Read by CPU returns undefined values.
As long as bit RMAP is set, the mapped special function register area can be accessed.
This bit is not cleared automatically by hardware. Thus, when non-mapped/mapped
registers are to be accessed, the bit RMAP must be cleared/set respectively by software.
All Special Function Registers (SFRs) with addresses whose address bits 0-2 are 0
(such as: 80_H, 88_H, 90_H, 98_H, …, F0_H, F8_H) are bit-addressable.
The 81 SFRs in the standard and mapped SFR areas include pointers and registers that
provide an interface between the CPU and the other on-chip peripherals. The SFRs of
the C508 are listed in Table 3-2 and Table 3-3. In Table 3-2, they are organized in
groups which refer to the functional blocks of the C508. Table 3-3 illustrates the contents
of the SFRs in numeric order by their addresses.
User’s Manual
3-11
2001-05