C509-L_97 SIEMENS [Siemens Semiconductor Group], C509-L_97 Datasheet - Page 42

• Manufacturer Part Number: C509-L_97
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

3.5
The registers, except the program counter and the four general purpose register banks, reside in
the special function register area. The special function register area consists of two portions: the
standard special function register area and two mapped special function register areas. Several
special function registers of the C509-L (CC10-17, CT1REL, CC1EN, CAFR) are located in the
mapped special function register area. For accessing the mapped special function register area, bit
RMAP in special function register SYSCON must be set. All other special function registers are
located in the standard special function register area.
For accessing the port direction registers, which define the input or output function of the
bidirectional port structure, bit PDIR in SFR IP1 is used. This port direction register access operates
similar to the mapped SFR accesses, but a double instruction sequence must be executed. The first
instruction has to set bit PDIR. Thereafter, the second instruction can read or write the direction
register. Further details about port direction selection see chapter 6.1.1.1.
The most right column of table 3-5 indicates if an SFR is accessed with a mapped procedure
controlled by either RMAP or PDIR.
Special Function Register SYSCON (Address B1 H )
Special Function Register IP1 (Address B9 H )
Bit
RMAP
PDIR
Semiconductor Group
Special Function Registers
Bit No. MSB
B1 H
B9 H
CLKP PMOD
PDIR
The functions of the shaded bits are not described in this section.
7
Function
Special function register map bit
RMAP = 0: The access to the non-mapped (standard) special function
RMAP = 1: The access to the mapped special function register area is
Direction register enable
PDIR = 0:
PDIR = 1:
PDIR will automatically be cleared after the second machine cycle (S2P2)
after having been set.
6
–
.5
5
1
register area is enabled (reset value).
enabled.
Port register access is enabled (reset value).
Direction register is enabled.
RMAP
.4
4
3-17
.3
3
–
.2
2
–
XMAP1
.1
1
Memory Organization
Reset Value : 1010XX01 B
Reset Value : 0X000000 B
XMAP0
LSB
.0
0
SYSCON
IP1
1997-10-01
C509-L