C509-L_97 Datasheet, PDF (82/290 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C509-L
Special Function Register SYSCON (Address B1H)
Special Function Register IP1 (Address B9H)
MSB
Bit No. 7
6
5
4
3
B1H CLKP PMOD 1 RMAP –
7
6
5
4
3
B9H PDIR –
.5
.4
.3
Reset Value : 1010XX01B
Reset Value : 0X000000B
LSB
2
1
0
– XMAP1 XMAP0 SYSCON
2
1
0
.2
.1
.0 IP1
Bit
PMOD
PDIR
The shaded bits are not used for port selection.
Function
Port mode selection
PMOD = 0: Quasi-bidirectional port structure is selected (reset value)
PMOD = 1: Bidirectional port structure is selected.
Direction register enable
PDIR = 0: Port register access is enabled (reset value)
PDIR = 1: Direction register is enabled.
PDIR will automatically be cleared after the second machine cycle (S2P2) after
having been set.
Direction Registers DIR0-DIR6, DIR9 (Mapped Address = Port Address) Reset Value : FFH
MSB
LSB
Bit No. 7
6
5
4
3
2
1
0
Address. =
Port-Addr.
.7
.6
.5
.4
.3
.2
.1
.0
Direction
Register
Bit
Bit 7...0
Function
Port driver circuitry, input/output selection
Bit = 0: Port line is in output mode
Bit = 1: Port line is in input mode (reset value).
This register can only be read and written by software when bit PDIR (IP1) was set
one instruction before.
Semiconductor Group
6-4
1997-10-01