C511_1 Datasheet, PDF (39/128 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Units
Figure 6-15c
Driver Circuit of Port 1 pins P1.3 and P1.5 (when used for SRI and SLS)
When enabling the SSC, inputs used for the SSC will be switched into a high-impedance mode.
For P1.3/SRI, Tristate will be enabled, when the SSC is enabled.
For P1.5/SLS, Tristate will be enabled, when the SSC is enabled and is switched to slave mode. In
master mode this pin will remain a regular I/O pin.
Semiconductor Group
6-6