Siemens EF 88H Series Manual de usuario descargar pdf (Pagina 110)

Device Specification

Semiconductor Group 7-48

with internal pull-up resistors. That means, when configured as inputs, ports 1 to 6 will be

pulled high and will source current when externally pulled low. Port 0 will float when configured

as input.

Port 0 and port 2 can be used to expand the program and data memory externally. During an

access to external memory, port 0 emits the low-order address byte and reads/writes the data

byte, while port 2 emits the high-order address byte. In this function, port 0 is not an open-drain

port, but uses a strong internal pull-up FET. Port 1, 3, 4, 5 and port 6 provide several alternate

functions. Please see the "Pin Description" for details.

Port pins show the information written to the port latches, when used as general purpose port.

When an alternate function is used, the port pin is controlled by the respective peripheral unit.

Therefore the port latch must contain a "one" for that function to operate. The same applies

when the port pins are used as inputs. Ports 1, 3, 4 and 5 are bit- addressable.

The SAB 80C517A has two dual-purpose input ports. The twelve port lines at port 7 and port

8 can be used as analog inputs for the A/D converter. If input voltages at P7 and P8 meet the

specified digital input levels (V

and V

) the port can also be used as digital input port.

In Hardware Power Down Mode the port pins and several control lines enter a floating state.

For more details see the section about Hardware Power Down Mode.

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Siemens EF 88H Series Manual de usuario Pagina 110