C509-L_97 SIEMENS [Siemens Semiconductor Group], C509-L_97 Datasheet - Page 88

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

6.1.1.3
6.1.1.3.1
Figure 6-7 shows the bidirectional port structure in the input mode.
Figure 6-7
Bidirectional Port Structure - Input Mode
The input mode for a port pin is selected by programming the corresponding direction bit to '1'
(QDL='1'). The FETs p1, p2, p3 and n1 are switched off. Through a Schmitt-Trigger, designed to
detect CMOS levels, the input signal is lead to the internal bus where it can be read by the
microcontroller.
Semiconductor Group
Bidirectional (CMOS) Port Structure
Input Mode
6-10
On-Chip Peripheral Components
1997-10-01
C509-L